ISSN:0260-1818    

DOI:10.1039/IC99491FX001

出版商:RSC    

年代:1994

数据来源: RSC

ISSN:0260-1818    

DOI:10.1039/IC99491BX003

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

3 Boron By M.A. BECKETT Department of Chemistry University of Wales Bangor LL57 2U W UK 1 Introduction This report takes a similar format to that used last year’ and reviews the chemistry of boron-containing compounds reported during 1994. The literature has been surveyed by use of Chemical Abstracts volumes 120 and 121 in conjunction with independent searches of BIDS and the principal chemical journals. 2 Reviews and Articles of General Interest The reader is directed specifically to two chapters in the Specialist Periodical Report ‘Organometallic Chemistry’ (Volume 24) for two reviews complementary to this report. The first review is a comprehensive account of the chemistry of carbooranes and metallocarboranes,2“ and the second review is a general account of the organometallic chemistry of Group 13 elements.2b The Eighth International Meeting on Boron Chemistry IMEBORON VIII took place in Knoxville Tennessee USA on July 11-15 1993.Lectures have now been published in The Royal Society of Chemistry publication ‘Current Topics in the Chemistry of Boron’ dedicated to the conference proceedings.’“ In total the seventy- one articles contained in this book have been categorized into one of six topic areas organoborane chemistry chiral organoboranes medical applications of boron carborane chemistry heteroborane derivatives and complex borohydrides and metalloborane chemistry. A high quality is maintained from all contributors and the book as a whole makes stimulating reading. Plenary lectures from the conference were also published in ‘Pure and Applied Papers of general interest this year include ‘The topology of coordination polyhedra M.A. Beckett Annu. Rep. Progr. Chem. Sect. A Inorg. Chem. 1993 90,Chapter 2 3. (a)C. E. Housecroft in ‘Organometallic Chemistry’ ed. E. W. Abel Specialist Periodical Report The Royal Society of Chemistry Cambridge Vol. 24 Chapter 3 p 26; (h) K. C. Molloy in ‘Organometallic Chemistry’ ed. E. W. Abel Specialist Periodical The Royal Society of Chemistry Cambridge Vol. 24 Chapter 4 p 48; (c) ‘Current Topics in the Chemistry of Boron’ ed. G. W. Kabalka The Royal Society of Chemistry 1994 Cambridge UK; (d) M.F. Hawthorne X. Yang and Z. Zheng Pure Appl. Chem. 1994 66 245; (e) P. Paetzold J. Miiller F. Meyer H.-P. Hansen and L. Schneider ibid.255; v) S. G. Shore ibid. 263; (g) R. B. King Polyhedron 1994,13,2005;(h)Y. V. Roberts and B. F. G. Johnson J. Chem. SOC.,Dalton Trans. 1994 759; (i) A. Derecskei-Kovacs B. I. Dunlap W. N. Lipscomb A. Lowrey D. S. Marynick and L. Massa Inorg. Chem. 1994,33 5617; (j)W. N. Lipscomb and L. Massa ibid. 5155; (k) M. D. Fryzuk B. R. Lloyd G. K. B. Clentsmith and S.J. Rettig .I. Am. Chem. SOC. 1994 116 3804; (I) R. Quyoum Q. Wang M.-J. Tudoret and M. C. Baird ibid. 6435; (m)D. C. Bradley Polyhedron 1994,13,1111;(n) D. E. Kaufmann and A. Otten Angew. Chem. Int. Ed. Engl. 1994 33 1832. 19 M. A. Beckett and their rearrangements’,2g ‘Dicarbadodecaborane rearrangements an appraisal of rotational mechanisms’,2h ‘Quantum chemical studies of boron fullerene analogues’,2’ and ‘Conjunct0 closo boranes and relationships to dual structures’.2j Unusual coordination behaviour of LiCBEt,] and NaCBEt,] is shown in binuclear palladium complexes with bridging hydrides,2k and [MeB(C6F,),] -has been shown to act as a carbocationic olefin polymerization initiator in [(q5-C,Me,)TiMe2][MeB(C,F,),].2’ A review concerned with metallo-organic precursors for depositing inorganic electronic materials has been published; it contains a section on the deposition of borides.,” The use of selective anion receptors from neutral boron-containing materials has been highlighted and reviewed.,” 3 Polyhedral Species Boranes.-Pulsed laser ablated B atoms reacted with H upon condensation with excess argon to yield BH a (H,)BH complex and B,H as the major products; product molecules have been identified from TR spectra by loB and D substitution and MBPT(2) calculations of vibrational frequencies.,“ Boron- 11NMR evidence has been reported for the stepwise generation of [BH3I2- and [B,H,I2- as discrete stable intermediates in the reduction of B2H6 by alkali metal naphthalides in thf; [B,H,] -and [BHJ were formed as the final product^.^' The molecular structures of 2,4-ethanotetraborane(lO) B,H,(CH,), and 1-(difluorobory1)-pentaborane(9) 1-(F,B)B,H, have been determined in the gas-phase by electron diffraction method^.^^^^ The structural parameters of these molecules agreed well with ab initio (MP2/6-31G*) optimized molecular geometries and the experimental NMR data agreed with IGLO calculated chemical shifts.The synthesis of [B,H,,-PMe,]- from B,H,.PMe and KH or NaCHBBu;] and its reactions with BCl or HCl to yield B,H,.PMe or B,H,,*PMe, respectively have been reported; the B,H,,-PMe adduct is described as the 1-isomer rather than the 2-isomer which is believed to be the product upon addition of a Lewis base to B,H ,.3e Three of the six possible linkage isomers of SnPh,(B,H,) have been reported from the reaction of K[B,H,] with SnCI,Ph,.3f The reported isomers were p-p’-SnPh,(B,H,), p-2’-SnPh,(B5H8), and p-1’-SnPh,(B,H,),(Figure 1) and a single crystal X-ray structural determination of the latter has been ~ndertaken.~f The gas-phase molecular structures of B,H, and B,H, have been redetermined by a combination of electron diffraction and ab initio computational techniques.The new geometries have improved R factors over the previously reported structures and calculated “B NMR chemical shifts (DZ/GED level) based on the new geometries (a)T.J. Tague Jr. and L. Andrews J. Am. Chem. Soc. 1994,116,4970;(h) R. A. Godfroid T. G. Hill T. P. Onak and S.G. Shore ibid. 12 107; (c) D. Hnyk P.T. Brain D.W.H. Rankin H.E. Robertson R. Greatrex,N. N. Greenwood M. Kirk M. Buhl and P. von Rague Schleyer Inory. Chem. 1994,33,2572:(d) P. T. Brain D. W. H. Rankin H. E. Robertson 1. L. Alberts M. Hofmann and P. von Rague Schleyer ihid. 2565; (e)P. Grundt and G. Kodama ihid. 2056; v) H. Fang D. Zhao L. Brammer and L. Barton J. Chem. Soc. Chem. Commun. 1994 1531; (g) P.T. Brain D. Hnyk D. W.H. Rankin M.Biihl and P. von Rague Schleyer Polyhedron 1994 13 1453; (h)T. P. Onak and R. E. Williams Inorg. Chem. 1994 33 5471; (i) A.M. Mebel K. Morokuma and D.G. Musaev J. Am. Chem. Soc. 1994 116 3932; (j) D. Dou I. J. Mavunkal J. A. K. Bauer C. B. Knobler M. F. Hawthorne,and S.G.Shore Znorg. Chem. 1994,33,6432;(k) S. A. Jasper Jr. R. B. Jones J. Mattern J. C. Huffman and L. J. Todd hid. 5620; (1) F. Meyer P. Paetzold and U. Englert Chem. Ber. 1994,127,93;(m)D. F. Gaines A. N. Bridges and R. K. Hayashi Inorg. Chrm. 1994,33 1243; (n)F. Meyer U. Englert and P. Paetzold Chem. Ber. 1994 127 853; (0) T. Jelinek J.D. Kennedy B. Stibr and M. Thornton-Pett J. Chem. Soc. Chem. Commun. 1994 1999. Boron 21 Figure 1 Reaction of Ph,SnCl,with [BsHs] -(Reproduced from J.Chem. Soc. Chem. Commun. 1994 1531) were in good agreement with experimental data.3s The structures of nido-y-2,3-(Me2B)B,H and nido-2-MeB6H,(y-3,4-H) with unsymmetrical bridge hydrogens have been reconfirmed via the ab initio/IGLO/NMR method.3h Cluster rearrangements in the pentagonal pyramidal clusters B6H, and [(h-B,H,)(CO)(PH,),] have been studied by computational methods at the MP2/6- 31G" and HF/6-31G levels.,' The reaction of [Et,NH],[B,oH,,J with MeCN in the presence of CF,COOH yielded [Et3NH][2-B,,H,NCCH,].3j This was in contrast to an earlier report that the 1-isomer was produced in a similar reaction in the presence of p-toluenesulfonic acid. The NMR spectra and X-ray structure of [NEt,H]-[B ,H,NCCH,] was reported. The reaction of[L,PdCl,] (L = PMe,Ph SMe,) with Li2[Bl,H,,~ or Li,[B,,H,,] at room temperature resulted in L di-substituted neutral boranes characterized by NMR spectroscopy 1,10- (PMe Ph) B ,H 1,6- (PMe P h),B ,,H 8 1,7-(PMe,Ph),Bi 2H 10 1,12-(Me,S),Bl 2H 10 1,7-(Me,S)2B 2H10 and 2,7(8)-(PMe,Ph),B,,H,.3k The latter compound which exists as a mixture of enantiomers has been characterized by X-ray crystallography.B,,H,,(SMe,) reacted with the phosphaalkyne PCBu' to form a product [BloH,,(SMe,)][CButPH][B,oH,2] in which the two {B,,) units are linked by a HP-CBu' bridge (Figure 2).3' The reaction of Na[B,,H,,] with CIBH,-SMe and proton sponge or the reaction of B,,H, with ClBH,.SMe and 2NaH led to nido-[B ,HI,] -.,"' Application of these reactions using 6-alkyldecaboranes (e.y.6-thexyldecaborane) provided the first synthesis of 7-substituted monoalkyl-undecaborane anions via regiospecific boron insertion chemistry. Condensation of two molecules of B,H,,(NHEt) at 140"C yielded the conjunct0 M. A. Beckett 0 BH B A + ,u-H Figure 2 Reaction ofB,,H,,(SMe,) with PC'Bu (Reproduced by permission from Chem Ber. 1994 127 93) boraneB,,H,,(l\iHEt,) whichcould be deprotonated to theanion [B,,H,,(NHEt,)]- which has been characterized by X-ray diffraction as its [NEt3(CH2Ph)]+ salt.," The compound Unti-BI8H2 has been shown to react with MeNC in an unusual reaction which led to 7-{ (MeNH)C,N,HMe,}-anti-B 8H20 with an imidazole-based carbene coordinated to the macropolyhedral cluster (Figure 3).,O Metal1oboranes.-Progress was made on metal-rich metalloboranes during 1994.4a-g The mixed-metal metallaborane B,H,FeCo(CO) was obtained in good yield from the reaction of [co,(C0)8] with B,H,Fe,(C0),.4a Deprotonation of [y-HFe,(CO),(p- CO)(p,-HB-)I with LiBu" yielded the dianionic species [Fe,(CO),(p3-HBC0)I2 -which has been characterized by spectroscopy; reaction of this anion with protons led to decomposition whilst reaction with FeCl led to [Fe,(CO),(p-CO)(p,-HBCl)] -which has been characterized by X-ray diffraction as its [AsPh,]' A facile reaction of [Fe,(CO) ,HBI2 -with either [Fe,(CO),] or [Fe(CO),(cis-cyclooctene)] led to sequential formation of [HFe,(CO),,B]2- [HFe,(CO),7B]2- and [HFe7(CO),,B]2-;the latter anion has been characterized crystallographically as its [AsPh,] salt which showed the boron atom residing inside a monocapped trigonal + prism of Fe atoms.4c The relationship between the geometric and electronic structures for metallaboranes with {M4B4) cluster cores has been explored by approximate (Fenske-Hall) molecular orbital theory.4d The butterfly cluster [Ru,H(CO),,BH(y- NCHMe)] which contains a semi-interstitial boron atom was prepared by photolysis of [Ru,(CO),BH,] in acetonitrile in the presence of [M(CO),] (M = Cr Mo W).4e The boride cluster anions [Rh,Ru,(CO),,B] -and [Rh,Ru,(CO),,B,]- have been characterized as being octahedral and double-prismatic by X-ray diffraction studies on the [N(PPh,),] salts; these compounds were formed together with the neutral + (a) C.S. Jun T. P. Fehlner Oryanometallics 1994 13 2145; (6) L.E.Crascall B. H. S. Thimmappa A. L. Rheingold R. Ostrander and T. P. Fehlner ibid. 2153; (c) A. Bandyopadhyay M. Shang C. S. Jun and T. P. Fehlner Znoi-g.Chem. 1994,33,3677; (d)T. P. Fehlner J. Organornet. Chem. 1994,478,49; (e)J. R. Galsworthy C. E. Housecroft J.S. Humphrey X. Song A. J. Edwards and A. L. Rheingold J. Chem. SOC. Dalton Trans. 1994 3273; v) J. R. Galsworthy C. E. Housecroft and A. L. Rheingold ibid. 2359; (y) J. R. Galsworthy C. E. Housecroft D. M. Matthews R. Ostrander and A. L. Rheingold ibid. 69. Boron 23 Figure 3 Molecular structure of [7-(MeNH)C2N2HMe,]-anti-B,,H, (Reproduced from J. Chem. Soc. Chem. Commun.,1994 1999) [Rh,Ru,H(CO) 6B] by treating [N(PPh,),][Ru,(CO),BH,] with [{Rh(CO) Cl}2] .4f The reaction of [N(PPh,),] [Ru,(CO),(B,H 5)] with [{ MCp*Cl,) ,] (M = Rh Ir) followed different routes depending upon M;for Rh one of the products is the 62-electron butterfly borido-cluster [RhRu3Cp*H(CO),BH2] whilst the Ir reactant led to the 64-electron cluster [I~RU~C~*H(CO),,BH,].~~ A number of papers appeared during 1994 concerning tetrahydroborates and their coordination cherni~try.~"-~ The osmium complex [OsHCl(CO)(PPr',),] was found to react with Na[BH,] and initially gave the tetrahydridoborate complex [OsH(y2-H,BH,)(CO)(PPr',),] which was isolated and characterized; in the presence of isopropanol it decomposed to the tetrahydride [OsH,(CO)(PPr',),] .5a The structure and reactivity of [Al(BH,),] has been studied by ab initio calculations taking into account correlation energy; changing the coordination mode from (y2 +y3) of one of the borohydride groups led to the y2,q2,q3 structure which is believed to be the transition state of the hydrogen exchange mechanism observed in 'H NMR spectros~opy.~~ [Al(BH,),] reacted with CO at ambient temperature to give BH,-CO (a)M.A. Esteruelas Y. Jean A. Lledos L. A. 010 N. Ruiz and F. Vol.atron Inorg. Chem. 1994,33,3609; (b)I. Demachy and F. Volatron ibid. 3965; (c)A. J. Downs and L. A. Jones Polyhedron 1994,13,2401;(d) K.S. Siddiqi F.M.A. M. Aqra S.A. Shah and S.A.A. Zaida ibid. 247; (e) D. Coucouvanis A. Hadjikyriacou,R. Lester and M. G. Kanatzidis Inorg. Chem. 1994,33 3645; (f) T. Arliguie M. Lance M. Nierlich J. Vigner and M. Ephritikhine J.Chem. Soc. Chem. Commun. 1994 847. M. A. Beckett and a colourless viscous liquid identified as [A1H(BH,),],.5c The interaction of GeCl and SnC1 with excess K[BH,] in dry thf led to the formation of [M(BH4),] (M = Ge Sn) in which the [BH,]- anion is coordinated to the Group 14 metal atom in a tridentate manner. 5d New zirconium thiolate complexes have been obtained from the acidification of [Zr(BH,),] with RSH; [Zr,S,(Bu'S),(BH,),(thf),l and [zr6s6(BU's),(BH,)8(thf)2] were obtained from Bu'SH.'' The anion [(BH,),U(p,q7,q7-C7H7)U(BH,),] -has been obtained by treatment of [U(BH,),] with K[C,H,] and the cation [U(BH,),(thf),]+ was produced by protonation of [U(B H ,),(t h f ),]with [NH E t ,][BPh,] in t h f. There have been fewer publications on boron-rich metalloboranes during 1994 than in previous years.6aA The reactions of [(Cp*CoCl},] with BH,.thf and Li[BH,] have been described; products include nido-1-{C~*CO)-~-((~~-C,M~,H)CO)B,H, arachno-Cp*CoB,H o nido-(2,4-Cp*Co) *B3H7 cIoso-2,3,4-(Cp*Co) 3B2H4 and closo-l,2,3-{Cp*C0},B,H,.~~ The analogous chromium dimer [{Cp*CrCl},] was found to react with BH,.thf to result in a brown diamagnetic solid [{Cp*Cr),B,H,] whose structure is believed to be similar to that of [(cp*Ta),(B,H,),] but with a Cr-Cr triple bond.6h The capped-closo species [1-(FeCp)-2-{Mo( PMe Ph),H)B ,H 7] has been prepared from the reaction of nido-[2-(FeCp)B5H with [Mo(PMe,Ph),H,] and has been characterized crystallographically (Figure 4) and by NMR spectroscopy; the structure reveals one Fe-Mo-B face capped by a boron atom and the other capped by a triply-bridging hydrogen atom.The isostructural W compound [1-{ FeCp}-2-{W(PMe,),H) B ,H 7] and nido-[2-(Re( PMe,),B,H 0] were reported.6' The metallaborane anions [Cu(Bl ,H and [Ni(B,,H 1)2]4-have been prepared from the reaction of [Me,NH][B ,HI,] in aqueous NaOH with CuO or NiCI, respectively. NMR XPS and cyclic voltammetry results were reported together with a single crystal X-ray diffraction study on [NBu;] CCu(B1,H 11121.6d Heteroboranes-The reader is directed to a Royal Society of Chemistry publication 'Specialist Periodical Report Organometallic Chemistry' for a comprehensive review of the 1994 literature concerning carbaboranes.'" The reaction of Me,Si(C-CMe) with excess Et,BH has been shown to sponta- neously lead to the formation of the endo-and exo-isomers (55% and 45% respectively) of the arachno-1-carbapentaborane(10) derivative [{p-2,5-C(Et)(SiMe,H)]-1-CEt-2,3,4,5-(BEt),H3]; this cluster type appears to be very stable and must be taken into consideration upon future investigations of multiply C-borylated organic cornpo~nds.~" A derivative with an ortho-phenylene link (a)Y.Nishihara K. J. Deck M. Shang T. P. Fehlner B. S. Haggerty and A. L. Rheingold Organometallics 1994,13,4510;(b)K. J. Deck Y. Nishihara M. Shang and T. P. Fehlner,J. Am. Chem. Soc. 1994,116,8408; (c)H. J. Bullick P. D. Grebenik M. L. H. Green A. K. Hughes J. B. Leach and P. Mountford J. Chem. Soc. Dalton Trans. 1994 3337; (d) J. G.Kester D. Keller J.C. Huffman M. A. Benefiel W. E. Geiger Jr. C. Atwood A. R. Siedle G.A. Korba and L. J. Todd Inorg. Chem. 1994 33 5438. ' (a)R. Koster G. Siedel and B. Wrackmeyer Angew. Chem. Int. Ed. Engl. 1994,33,2294;(b)B. Gangnus H. Stock W. Siebert M. Hofmann and P. von Rag& Schleyer ibid, 2296; (c)M.A. Fox R.Greatrex M. Hofmann P. von Rague Schleyer ibid. 2298; (d) J. PleSek B. Stibr X. L. R. Fontaine T. Jelinek M. Thornton-Pett S. Heimanek and J.D. Kennedy Inorg. Chem.. 1994 33 2994; (e) M.A. Fox and R. Greatrex J. Chem. Soc. Dalton Trans. 1994,3197;v) A. Ceulemans G. Goijens and M. T. Nguyen J. Am. Chem. SOC.,1994,116,9395; (g) T. Jelinek J. Holub B. Stibr X. L. R. Fontaine and J. D. Kennedy Collect. Czech. Chem. Cornmun. 1994 59 1584; (h) J. Holub B.Stibr Z. JanouSek J. D. Kennedy and M. Thornton-Pett Inorg. Chim. Acta 1994 221 5; (i) R.H. Pak R.R. Kane C. B. Knobler and M. F. Boron 25 Figure 4 Molecular structure of the capped closo species [(FeCp){Mo(PMe,Ph),H)B,H,I (Reproduced by permission from J. Chern. SOC.,Dalton Trans. 1994 3337) 1-alkyl-(2,5-ortho-phenylene)-1-carbapentaborane( lo) has also been prepared.7b The reactions of arachno-B,H, with alkynes (MeCCH EtCCH and MeCCMe) to yield alkyl derivatives of arachno-pentaborane( 10) have been described; reported and characterized compounds include l-R-1-C-(p-2,5-X)B4H (R = Me X = CH, endo-CHMe exo-CHMe; R = H X = endo-CHMe exo-CHEt; R = Et X = CH,) with structures supported by IGLO chemical shift calc~lations.~~ The monocarbaborane base adducts endo-9-Me-8-(NMe3)-arachno-6-CB,H , 9-Me-8-L-nido-6-CB9H (L = NMe, OH-) and exo-6-L-arachno-4-CB8H12(L = SMe, NMe, urotropine pyridine quinoline MeCN PPh, and MeNC) have been prepared from the regiospecific cluster degradation reactions of closo-1,2-C,BloH ,in the presence of Lewis base (L) which proceeded via the nido-[7,9-C,BloHl,] -anion intermediate.7d The true identity of the 'bare-carbon' cluster 'closo-C,B,H,' has been revealed as closo-2,3-C2B,H by careful re-evaluation of reported NMR data.,' A detailed ab initio study of the rearrangement of C,B,H revealed that the carborane is fluxional along the closo-nido opening mode and could rearrange via a consecutive double diamond-square-diamond me~hanism.,~ Deprotonation of the neutral arachno-C,B,H, with either proton sponge or K,C0,/[NMe4]C1 led to the formation of the arachno anion [4,5-C,B7H ,] -in high yield; new nine-vertex hypho-dicarbaboranes (R exo-5-(NR,)-hypho-4,9-C2B7H13= Me Et) have been prepared by the addition of NR to C2B,H ,in CH,Cl solution whilst reaction with NaCN in aqueous solution resulted in removal of one boron vertex and the generation albeit in small yield of the eight-vertex hypho-[7,8-C,B,Hl,] -anion.7g NH,Pr" and NH when reacted with nido-5,6-C,B,Hl in CH,Cl at room temperature gave the exo-9-L-arachno-5,6- Hawthorne Inory.Chern. 1994 33 5355; (j)D. Hnyk P.T. Brain H. E. Robertson D.W. Rankin M. Hofmann P. von Rague Schleyer. and M. Buhl J. Chern. SOC.,Dalton Truns. 1994 2885 (k) D. Hnyk D.W. H. Rankin H. E. Robertson M. Hofmann P. von Rague Schleyer and M. Biihl Inorg. Chern. 1994 33 4781. M. A. Beckett C,B,H, ligand derivatives whereas the tertiary amines (L = NEt, NBu:) afforded isomeric compounds exo-6-L-5,10-C,B8H 2; the parent anion arachno-[5,10-C2B8H,,] -has been prepared from the reaction of exo-6-(NEt,)-5,10-C2B,H, with Na metal in thf.7h The synthesis and structural characterization of [Me,NH][nido- 9,l 1-12-7,8-C,B,Hlo] and [Me,NH][nido-9-I-7,8-C2B9H1 ,] have been rep~rted.~' The molecular structures of 1 ,7-C12- 1,7-dicarba-closo-dodecaborane( 12) (1 ,7-C12-1 ,7- C2B,,H,,) and 1,2-dicarbadecaborane(lO)(C2B8H10) have been studied by electron diffraction methods and icosahedral and bicapped square antiprimatic structures modelled; the reliability of the experimental structures was assessed by ab initio (MP2/6-31" level) optimized structures in concert with IGLO calculations on "B NMR chemical ~hifts.~j*'~ There has been considerable progress in aza-,"" and thiaboranesdPh chemistry during 1994.Thus reactions between arachno-4-NB8H ,with Lewis bases (py quin isoquin urotropin and MeCN) have lead to the isolation and characterization of exo-6-L-arachno-4-NB8Hl adducts." A new route to closo-NB ,H, has been described starting from nido-NB,H, by interaction with Me,S-BH at 140 "C to form closo-Me,SBH,NB ,H ,;the N-bonded ligand to Me,SBH was removed with Bu'NH~.'~ The first macropolyhedral eighteen-vertex azaborane anti-9-NB1 7H, has been obtained from n-butylnitrite and anti-B,,H, in 1&15'/0 yield; it was character- ized by NMR and MS measurements.8' The first nido-thianonaborane nido-[9-S- B,H,] -has been prepared from deprotonation of exo-6-(SMe2)-arachno-4-sB8Hlo by NaH or Na metal; it could be reconverted back into the exo-L-arachno-4-SB8H, series (L = SMe, py) by action of the Lewis base followed by acidification with CF3COOH.8dA series of these eXo-L-UrUChno-4-SB8Hlo clusters (L = SMe, PPh, MeCN NMe, py urotropine MeNC quin) have been prepared from arachno-4- SB8H12 or nido-6-SB,H1 ,and the corresponding Lewis bases; X-ray crystal structure of three representative adducts (L = urotropine 1/2urotropine MeNC) have been reported.8e The reaction of [nido-6-SB,H1 ,I-with s8 resulted in the 11-vertex arachno-dithiaborane cluster anion [2,3-S2B,H,,] -.sf Reactions of [arachno-2,3-S,B,H,,]-with H2S0, MeI and CH,12 have been reported and dehydrogenation of arachno-2-H-2,3-S,B,Hlo gave the previously described compound nido-7,9-S2B,H,.8f Thermolysis of arachno-4-SB,H1 in cyclohexane has been shown to generate the eighteen-vertex macropolyhedral anti-9,9'-S,B,,Hl in modest (1 8%) yield.8g The macropolyhedral anion [S,B,,H,,]- isolated in 48% yield as its [PPh,] + salt has been obtained from the action of elemental sulfur on a solution of the anti-[B ,H2,I2- anion and has been characterized by X-ray diffraction (Figure 5)and (a) T. Jelinek B. Stibr and J. D. Kennedy Collect. Czech. Chem. Commun. 1994,59,2244;(b)L. Schneider U. Englert and P. Paetzold Chem.Ber. 1994,127,87; (c) T. Jelinek J. D. Kennedy and B. Stibr J. Chem. Soc. Chem. Commun. 1994 677; (d)J. Holub J. D. Kennedy and B. Sibr Collect. Czech. Chem. Commun. 1994,59,367;(e)J. Holub B. Stibr,J. D. Kennedy M. Thornton-Pett,T. Jelinek and J. PleSek Inorg. Chem. 1994,33,4545; (f) J. Holub A. E. Wille B. Stibr P. J. Carroll and L. G. Sneddon Inory. Chem. 1994,33 4920; (y) T. Jelinek J. D. Kennedy and B. Stibr J. Chem. SOC.,Chem. Commun. 1994,1415; (h)T. Jelinek J.D. Kennedy B. Stibr and M. Thornton-Pett Angew. Chem. Int. Ed. Engl. 1994 33 1599; (if N.S. Hosrnane K.-J. Lu A. K. Saxena H. Zhang J. A. Maguire A. H. Cowley and R.D. Schluter Orgunometal-lics 1994 13 979; (j)N.S. Hosrnane L. Jia H. Zhang and J. A. Maguire ibid. 1411; (k) J. Holub J. D. Kennedy T.Jelinek and B. Stibr J. Chem. Soc. Dalton Trans. 1994,1317; (I) M. L. McKee Inorg. Chem. 1994 33 6213; (m) E. D. Jernrnis G. Subrarnanian and G. N.Srinivas ihid. 2317; (n) E. D. Jemrnis G. Subramanian and B. V. Prasad ibid. 2046. Boron 27 U Figure 5 Molecular structure oj the macropolyhedral [S,B,,H Janion (Reproduced by permission from Angew Chem. Znt. Ed. Engl. 1994 33 1600) NMR spectroscopy; the principal other product from this reaction was the known nido-[7-SBl,Hl 1]-anion (45%).8h The synthesis of c2oso-indacarbaboranes and their reactions with the bis(bidendate) Lewis base 2,2’-pyrimidine have been studied; the crystal structures of closo-l- (Me,CH)-1-Tn-2,3-(SiMe,),-2,3-C,B4H4 and 1 -(2,2’-C8H6N,)-1 -(Me,CH)-1 -In-2,3- (SiMe,),-2,3-C2B,H have been described.8i The synthesis reactivity and spectro- scopic properties of the ‘carbons-apart’ closo-l-Sn-2-(%Me,)-4-(R)-2,4-C2B4H4 and the crystal structures of the donor-acceptor complexes l-Sn(L)-2,4-(SiMe3),-2,4-C,B,H (R = SiMe, Me; L = 2,2’-CloH8N, 2,2’-C8HnN4 and [CpFe(yS-C,H,CH,NMe,)]) have been reported.8j The new ten-vertex carbathioaborane arachno-6,9-CSB8H, has been prepared by the reaction of arachno-4-CB8H14 with elemental sulfur and triethylamine in chloroform solution.8k A series of further thiacarbaborane species have been prepared from this compound arachno-[6,9-CSB8Hl1] - nido-7’9-CSB,Hl 1 arachno-4,6-CSB,Hl 1 nido-[6,9-CSB8H,] - and hypho-[7,8-CSB6Hl 1] -.8k A series of 9-and 10-vertex nido and arachno heteroboranes have been studied by ab initio methods (HF/6-31G*) and bond distances found to be in good agreement with X-ray data.8z ab initio MO studies on a series of pyramidal B,H,X structures (X =NH+ N CH EH- P PH’ SiH NO PO Co(CO),} indicate that for X = NH+ N and NO the terminal hydrogens of the basal ring pointed towards the direction of the capping group whilst with the other capping fragments these hydrogen atoms pointed away from the cap.8m A theoretical study on the isomer preferences of the 5- 6- and 7-vertex monoheteroboranes has been published.8” Metal1oheteroboranes.-A dimeric metallaheteroborane [(Pd(PPh,)(S,B,H,)},] with heteroatoms acting as both cluster atoms and two-electron donor sites has been obtained from the attempted recrystallization in MePh/CH,CI of a product obtained from the reaction of [PdCl,(PPh,),] with hypho-[7,8-S,B6H,] -;the dimeric product M.A. Beckett has been characterized cry~tallographically.~" Reactions of [MCI(PPh,),] (M = Rh Ir) with arachno-[S,B,H,,] -yielded cluster species nido-[(PPh3),HIrS,B,H9] nido-[(PPh,),HRhS,B,H,] nido-[(PPh,),RhSB,H,,1 and a complex [(PPh,),H,Ir(S,B,H,,)] in which the cluster-metal interaction occurred solely via a heteroatom q1 two-electron/two-centre cluster-to-metal donor bond.9b Ten vertex polyhedral azametallaborane chemistry has been developed with the preparation of arachno 9-((PMe2Ph),Pt}-6-NH-B8Hlo and nido 8-{ArRu)-6-NH-B,HlO (Ar = C&, MeC,H,Pr') species from reactions of cis-[PtCl,(PMe,Ph),] or [(Ar- RuCl,),] with appropriate azaborane The rhodium atom in the rhodatelluradodecaborane( 12) c/oso-2-(Rh(PPh,)(PhNHCS2))-1-Te-B ,H , is bonded to a triphenylphosphine and a N-phenyldithiocarbamate ligand; the Rh-Te distance is 2.5812(3)A and the structure is consistent with Wade's rules with the { Rh(q2-S,CNHPh)(PPh3)) unit equivalent to (BH} and the 'naked' {Te) cluster vertex equivalent to {BH2-).9d A c ombination of arachno-4'6-CSB7H cis-[PtCl,(PMe,Ph),] and a base (proton sponge) have been reacted to furnish the arachno cluster 9-{Pt(PMe,Ph),}-6,8-CSB7H9 in 41 % yield; thermolysis of this com- pound resulted in ortho-cycloboronation rather than cluster degradation to afford 9.9-(PMe,Ph)(PMe,-ortho-C6H~)-~ruchno-9,6,8-PtCSB7H~-lO in 51% yield." Following on from last year a brief survey of the more important developments in metallocarborane chemistry is included in this section; a comprehensive review of this area is available.," Thermolysis of the metallamonocarbaborane cluster 7-((CO)(PPh3),Ir)-1 -CB,H at 250 "C resulted in isomerization to afford 7-( (CO)H(PPh,)Ir}-9-PPh3-1-CB7H7 and 7-{(CO)H(PPh,)Ir)-6-PPh3-1-CB7H7 as the major products."' These clusters have quadrilateral open faces (B-B 220 pm) and isonido geometries although of formal closo constitution (Figure 6).The reaction of [NMe4][7-SMe-8-Me-nido-7,8-(a)M. Murphy T. R. Spalding J. D. Kennedy M.Thornton-Pett K. M. A. Malik M. B. Hursthouse and J. Holub J. Chem.Soc. Chem. Commun. 1994,2403; (b)R. Macias J. Holub J. D. Kennedy B. Stibr and M.Thornton-Pett ibid.,2265; (c) J. H. Jones B. Stibr J. D.Kennedy and M. Thornton-Pett Inorg. Chim. Acta 1994,227,163; (d)G. Ferguson D. O'Connell and T. R. Spalding Acta Crystallogr. Sect. C 1994 SO 1432; (e)J. H. Jones J. D. Kennedy and B. Stibr Inorg. Chim. Acta 1994 218 1. 'O (a)B. Stibr J. D. Kennedy E. Drdakovi and M. Thornton-Pett J. Chem.Soc. Dalton Trans. 1994,229; (b) F. Teixidor C. Viiias J. Casabo A. M. Romerosa J. Rius and C. Miravitlles Organometallics 1994 13 914; (c) J. Cowie B. D. Reid J. M. S. Watmough and A. J. Welch J. Organomet. Chem. 1994,481,283; (d) K. J. Adams J. Cowie S.G. D. Henderson G. J. McCormick and A. J. Welch ibid. C9; (e)G. 0.Kyd L. J. Yellowlees and A. J. Welch J. Chem. Soc. Dalton Trans. 1994,3129; v) K. F. Shaw B.D. Reid and A.J. Welch J. Organomet. Chem. 1994,482,207; (g) G. Ferguson J. F. Gallagher M. C.Jennings S. Coughlan T. R. Spalding J. D. Kennedy and X. L. R. Fontaine J. Chem.Soc. Chem. Commun. 1994 1595; (h)Y.-W. Park J. Kim and Y. Do Inorg. Chem. 1994 33 1; (i)F. Teixidor J. A. Ayllon C. Viiias R. Kivekas R. Sillanpad and J. Casabo Organometallics 1994,13,275 1 ;0)F.Teixidor J. A. Ayllon C. Viiias R. Kivekas R. Sillanpaa and J. Casab6,'J. Organornet. Chem. 1994,483 153; (k)J. C. Jeffery P.A. Jelliss and F. G. A. Stone J. Chem. Soc. Dafton Trans. 1994 25; (I) J.C. Jeffery P.A. Jelliss and F.G.A. Stone Organomet~6~ics, 1994 13 2651 ; (m) N. Carr D. F. Mullica E. L. Sappenfield and F. G. A. Stone Inorg. Chem. 1994,33 1666; (n)K. A. Fallis D. F. Mullica E. L. Sappenfield and F.G.A. Stone ibid. 4927; (0) D. F. Mullica E. L. Sappenfield F. G. A. Stone and S.F. Woollam Organometallics 1994,13 157; (p) S. J. Dossett S. Li D. F. Mullica E. L. Sappenfield and F. G.A. Stone ibid. 822; (4)J. M. Forward D. M. P. Mingos and A. V. Powell J. Organomet. Chem. 1994 465 251; (r) Y.-K. Yan D. M. P. Mingos T. E. Muller D. J. Williams and M. Kurmoo J. Chem. Soc. Dalton Trans. 1994,1735; (s)I. Cisaiova K. Maly and L. Hummel Acta Crystallogr. Sect. C 1994 SO 198; (t) 0.Ki-ii A. L. Rheingold M. Shang and T. P. Fehlner Inorg. Chem. 1994 33 3777; (u) E. Bembenek 0.Crespo M.C. Gimeno P.G. Jones and A. Lugano Chem. Ber. 1994,127,835; (u) 0.Crespo M. C. Gimeno P. G. Jones and A. Laguna Inorg. Chem. 1994,33,6128; (w)S. Li D. F. Mullica E. L. Sappenfield and F.G. A. Stone J. Organomet. Chem. 1994 467 95. Boron 29 C(221) 7 Figure 6 Molecular structure of [(CO)(PPh,),IrCB,H,] (Reproduced from J. Chem. Soc. Dalton Trans. 1994 231) C,B,H,,] with [RuCl,(PPh,),] led to the formation of [(PPh3),Ru-7-SMe-8-Me-7,8-(5)-C2B8HllJ with a new C2B carborane ligand which has a peculiar arachno structure resulting from the elimination of B(5) from the former [C2B,Hl2]- nido precursor; the geometry is basket-like with a B-B handle.'Ob A series of papers assessing steric effects of C-substituted metalladicarbaboranes have been published."'-' Crystallographic studies on l-Ph-3-mes-3,1,2-clos-RuC,B,H, and 1-Ph-2-Me-3-(cym)-3,1,2-closo-RuC,B, 1-1 revealed that whereas the former contains an essentially undistorted (RuC,B,) framework there was some indication that in the latter a polyhedral deformation from closo towards pseudo closo had just begun."' In ((PPh,)Cu},Ph,C,B,H and {(o-tol),PCu},Ph,C,B,H one copper atom is exo-facially bonded to the B(8)B(9)B(12) triangular face whilst the other copper atom occupies a polyhedral vertex position but is slipped away from the cage carbons; this slippage was more marked in the (0-tol),P derivative."" The compounds 1-Ph-3-(cod)-3,1,2-MC,B,H,,(M = Pd Pt) 1,2-Ph2-3-(cod)-3,1,2- PdC,B,H, and 1,11-Ph2-3-(cod)-3,1,1 1-PtC2B9H have been prepared from reac- tions between Tl,[7-Ph-nido-7,8-C,B9Hlo] and or T1,[7,8-Ph,-nido-7,8-C2B9H9] [MCl (cod)].The structure of (cod)PdPh,C,B,H revealed severe intramolecular crowding with the Pd atom slipped by 0.56 8 away from the phenyl groups and the cage deformed with extended C-B distances in the ligand face.'" Eight new complexes of mono- and di-ether carboranes with Ru Rh Pd Pt Hg La and U as metal vertices have been prepared by reactions between appropriate metal substrates and either a suspension of Tl,[7-CH,OMe)-7,8-nido-C2B9Hlo] or M2[7,8-(CH2OMe),-7,8-nido-C,B,H,] (M = T1 Li); crystallographic studies revealed that as the formal coordina- tion number of the metal decreased there was an increased interaction between the pendant ether oxygen atom@) and the metal atom.lof Novel phosphonium-betaine ligands [SC(H)PPh,] -and [S(H)C=C(PPh,)S] -have been stabilized in the 12-vertex closo rhodacarborane complexes [3-(q2- M.A. Beckett n Figure 7 Molecular structure of [(Ag(SbPh,)}2(C2B,H,2)2] (Reproduced by permission from Inorg. Chem. 1994,33 2) SC(H)PPh,)-3-(PPh,)-3,1,2-RhC2B,H,and [2-{q2-S(H)C=C(PPh,)S}-2,1 ,7-J RhC2B,Hl which were characterized by X-ray diffraction and spectroscopic methods.log A brief account of the synthesis and structure of the dimeric argentacar- boranes [9,9'-{Ag(EPh,)2}2-4,9,4,9'-(p-H,)-7,8,7',8'-nido-(C2B9Hlo)2](E = As Sb) has appeared; the molecular structure of the SbPh derivative is shown in Figure 7."" Sixteen exo-ruthenium@) complexes derived from [7,8-p(SRS)-7,8-C2B9Hlo]-ligands (R = CH2 (CH2)2 (CH2)3 (CH2)4 {CH2CH20CH2},, {CH2CH20CH2CH2}20) have been prepared and characterized; the ruthenium(i1) centres are bound to the clusters via two S-donor interactions and a bridging Ru-H-B(3) bond with the length of the S,S' connecting chain modifying the Ru-B(3) distance."' The crystal structure of [(PPh3)Hg{7,8-p-(SCH2S)-7,8-C2B9H9}] has been determined and shows that the Hg" centre is coordinated to the three boron atoms in the (C2B3) 'open-face' of the ligand."j New gold carbaborane complexes have been prepared from [NEt4][ 10-endo-(Au(PPh,))-7,8-Me2-nido-7,8-C2B,H9] and [AuCI(PPh,)] ;a di-gold and a tri-gold species have been structurally characterized.lok The reactions of the new aura- carborane reagent TI[10-endo-Au(tht)-7,8-Me,-nido-7,8-C2B9H9] with the Boron 31 alkylidyne(cyclopentadieny1) metal complexes [M(CR)(CO),Cp] (M = Mo W; R = aryl) have been studied; products described include [NEt4][[ lO-endo-{ AuW(p CC,H,Me,-2,6)(CO),Cp}-7,8-Me2-nido-7,8-C2B9H9] and [9,9'-exo-(Au,Mo(p,-CC,H,Me-4)(CO),Cp}-7,7',8,8'-Me,-nid0-7,7',8,8'-(C~B~H~)~].~~~ The synthesis protonation and ligand substitution reactions of anionic allyl(carborane) complexes (derived from e.g.nido-7,8-Me,-7,8-C,B9H9) of Ni Pd and Pt have been de- scribed.lorn,' Treatment of the salts [NEt,][Mo(CO),(q3-C3Hs)(qs-7,8-R,-7,8-C2B,H,] (R = H Me) with [CPh,][BF,] in CH,CI in the presence of donor molecules (L) afforded the cluster substitution products [Mo(C0),(q3-C,H,)(qs-7,8-R,-7,8-C,B9H,-10-L)] (R = H L = OEt,; R = Me L = OEt, thf SMe, PPh, py) and the structure of [Mo( C0) ,(q -C H ) (q -7,8 -Me ,-7,8 -C ,B H -10-0E t ,)] has been established by X-ray crystallography.loo The reactivity of bis(a1kyne) carborane complexes of Mo and W (e.g. [Mo(CO)(q2-MeC,Me),(q5-7,8-Me2-7,8-C2B9H9]) towards Bu'NC has been reported.loP The salts [FeCpz][M(C,B,H,,),] (M = Cr Fe Ni) have been prepared from the metathesis of [FeCpzICl and [NMe,][M(C,B,H 1)2].'0q These three salts were isostructural with one another and magnetic studies showed that they obeyed the Curie-Weiss law between 6 and 296K. The synthesis and structure of the charge compensated ferracarborane [3,3'-Fe(4-(Me,S)-1,2-C2B9H ,,},I and its charge-trans- fer salt with 2-3-dichloro-5,6-dicyano-p-benzoquinone was reported; magnetic measurements were also discussed.lorThe crystal structure of the bridged bis(dicarbadodecaborane)cobalt(m) cluster [8,8'-p-(MeOCOCH2NH)-3,3'-Co-1,2,1'2'-(C2B9Hlo) has been published."" The synthesis of metal carboxylates [M'1(1,2-C,B,oH,,C0,),] (M = Zn Cu Ni and Mo) and [M"{1,2-C,B,,H,,(CO,),f] (M = Cu Ni) have been reported and compounds were characterized spectroscopically; the thermolysis of these species has been investigated by weight loss TR spectroscopy and the isolation of volatile products.Or Solid state products from this thermolysis were characterized by elemental analysis powder X-ray diffraction and X-ray photoelectron spectroscopy.' Or Silver and gold complexes of the bis(diphenylphosphany1)-o-carboraneligand have been AgX (X-= [ClOJ [NO,]-) reacted readily with (PPh,),C,BloHlo to form complexes [AgX(PPh,),C,B,,H,,]; when X = [ClO,] -ligand displacement reactions readily afforded three- or four-coordinate Ag' com-plexes [AgL(PPh,),C,B,,H,,][C104] (L = PPh, PMe,Ph SPPh,) [AgL,(PPh,),C,B,,H lo][CIO,] (L = phen bipy (PPh,),C,B,,H ,,).lo" A number of four-coordinate gold(1) species containing the (PPh,),C,B,,H, ligand have been reported and the crystal structure of [Au{(PPh,),C,B,,H,,)((SPPh2)2CH2}][C104]~ CH,Cl has been described.' O" The synthesis of the complexes [N(PPh,),][M(CO),(q3-C,Hs)(q6-7,9-C,BloH,,Me,] (M = Mo W) and the crystal structure of [N(PPh,),] [WBr(CO),(q6-7,9-C,BloHloMe2)] have been reported; the latter clusters are best viewed as closo 13-vertex species (Figure 8).loW 4 Metal-catalysed Hydroboration Reactions Potential energy surfaces for rhodium(1)-catalysed olefin hydroboration reactions have been studied by ab initio molecular orbital calculations at the MP2/ECP + DZ M.A. Beckett Figure 8 Molecular structure qf[WBr(CO),(C2B,,H,,Me2)] -asfound in its [N(PPh,),] + salt. (Reproduced by permission from J. Organomet. Chem. 1994 467 97) level."' Catalysed hydroborations of several 1,l-disubstituted aryl alkenes have been studied and the mechanistic implications of phosphine-to-rhodium catalyst ratios on regioselectivities and enantioselectivities have been discussed. Ib The molecular structures of B,cat and its 4-But and 33-B~ derivatives have been determined by single crystal X-ray diffraction studies; these compounds react with [((PPh,),RhCl},] and [Rh(PPh,),Cl] by oxidative-addition to yield [Rh(PPh,),(Bcat),Cl] deriva-tives.' lC Bond dissociation energies of a series of B-H and B-C bonds in boranes have been calculated and an estimate of 66kcal/mol for the Ir-B bond strength in [Ir(CO)(PPh,),ClH(Bcat)] has been obtained using the calculated B-H bond dissociation energy of HBcat (11 1 kcal/mol); this Ir-B bond dissociation energy greatly exceeds the bond dissociation energy of the Ir-Me bond in trans-[Ir(CO)(PPh,),ClMeI] of 35 kcal/mol."d The addition of HBcat to the low-valent [CpRu(PPh,),Me] complex led to the formation of [CpRu(PPh,),H] and MeBcat by a mechanism more characteristic of high-valent metal centres; kinetic data were consistent with a mechanism which proceeded via a four-centred transition state that involved partial cleavage of the B-H bond during the formation of the B-C bond."" Regioisomers of the first tantalum boryl complexes endo-[Cp,TaH,(Bcat)] and exo-[Cp,TaH,(Bcat)] have been prepared from [(Cp,TaH,Li),] in MePh at -78 "C;the single crystal X-ray diffraction structures of both regioisomers have been (a) D.G.Musaev A. M. Mebel and K. Morokuma,J. Am. Chem. Soc. 1994,116,lO 693; (b) K. Burgess and W. A. van der Donk Inorg. Chim. Acta 1994,220,93; (c)P. Nguyen G. Lesley N. J. Taylor T. B. Marder N. L. Pickett W. Clegg M. R. J. Elsegood and N.C. Norman Inory. Chem. 1994 33 4623; (d) P. R. Rablen J. F. Hartwig and S. P. Nolan J. Am. Chern. Soc. 1994 116,4121; (e)J. F. Hartwig S. Bhandari and P. R. Rablen ibid. 1839; v) D. R. Lantero D.H. Motry D. L. Ward and M. R. Smith 111 ibid.10 81 1; (9)K. Burgess and W. A. van der Donk Organornetallics 1994,13,3616; (h)H. Wadepohl G.P. Elliot H. Pritzkow. F.G.A. Stone and A. Wolf J. Organornet. Chern. 1994 482 243. Boron 33 Figure 9 ORTEP drawings of endo-and exo-[Cp,TaH,(Bcat)] (Reproduced by permission from J. Am. Chem. Soc. 1994 116 10 81 1) determined (Figure 9).'lf Although there is some evidence that the metal may be directly involved in a few cases the TiCl and [Ti(OPr'),] 'catalysed' alkene/[BH,] -hydroboration reactions have been shown to predominately involve formation of BH in situ.''g Hydroboration of the carbon-tungsten triple bonds of the Fischer-carbyne com- plexes [Cp(CO),WC(p-tolyl)] and [Cp*(CO),WC(p-tolyl)] have been demonstrated for H,B,Et where the boryl substituted q3 benzyl complexes [(C,R,)(CO),W(a-1,2- q3-BEt,((p-methyl)benzyl)l (R = H Me) were obtained; the boron-containing ligands are bound in an a,l,2-q3 enylic fashion to the tungsten atoms.'lh 5 Heterocycles Containing Boron Boron-Carbon Ring Systems.-The X-ray determined structures of the borole hydrido iron complexes [CpFeH(Me,CTB Ph)] and [(C,H4Me)FeH(2,5-Me,CXB Ph)] showed the presence of an Fe-H-B three-centre bond with a weak B-H interaction (Figure 1O).I2" A new class of amphoteric molecule having Lewis acidic and Lewis basic sties have been prepared from the reaction .of [Cp*MCl,] (M = Zr Hf) with the substituted aminoborollide Li,[C,H,B NPri].Products characterized as [Cp*M(C?B NPr',)Cl,.Li(OEt 2 ) 32-were readily protonated by HC1 to afford zwitterionic dichlorides [Cp*M -(C,H,B N+HPr',)Cl,].' 2b The 1-t-butyl-2-methyl- 1,2-azaborolyl lithium salt (LiAb) and TlCl equilibrate at -75 "C under the action of light to give LiCl and TlAb.The reaction of TlAb with Ph,PCl gave the expected Ph,P-substituted azaborole ring in high yield whilst the lithium salt reacted with Ph,PCl to give only a small quantity of this product.'2c The first sixteen valence-electron iron sandwich compound (a)G. E. Herberich T. Carstensen D. P. J. Koffer N. Klaff R. Boese I. Hyla-Kryspin R. Gleiter M. Stephan H. Meth and U. Zenneck Organometallics 1994 13 619; (b) R. W. Quan G. C. Bazan A. F. Kiely W. P. Schaefer and J. E. Bercaw J. Am. Ckem. SOC.,1994,116,4489;(c)G. Schmid J. Reschke and R.Boese Chem. Ber. 1994,127,1891; (d)W. Siebert R. Hettrich and H. Pritzkow Angew. Ckem. Int. Ed. Engl. 1994,33 203; (e) B. Gangus A. Fessenbecker H. Pritzkow and W. Siebert Ckem. Ber. 1994,127 2393; (f) C. Balzereit H.-J. Winkler W. Massa and A. Berndt Angew. Ckem.,Int. Ed. Engl. 1994,33,2306; (g) B. Deobald J. Hauss H. Pritzkow D. Steiner A. Berndt and W. Seibert J. Orgunomet. Ckem. 1994 481,205; (h)A. J. Ashe 111 W. Klein. and R. Rousseau ibid. 468 21; (i) A. Hergel H. Pritzkow and W. Siebert Angew. Chem. Int. Ed. Engl. 1994,33 1247; (j)P. Frankhauser M. Driess H. Pritzkow and W. Siebert Ckem.Ber. 1994,127,329;(k)W. Weinmann H. Pritzkow and W. Siebert,ibid. 61 1; (I) A. Kramer H. Pritzkow and W. Siebert ibid. 1047. M. A. Beckett Figure 10 Molecular structure of [(C,H4Me)FeH(2,5-Me,C,H,BPh)] (Reproduced by permission from Organometallics 1994 13 621) Figure 11 Molecular structure of [(Ni(cod)),{C,H,(BMe),C=CC4H,] (Reproduced by permission from Chem.Ber. 1994 127 2394) [Cp*Fe{B(Et)C(Me)B(Et)C(Pri)C(Pri)>] has been characterized by a single crystal structure analysis which reveals a severely folded 2,3-dihydro- 1,3-diborolyl ring. 12d The reactions of 1,4-dihydr0-1,4-diborapentafulvenederivatives with [M (co~)~] (M = Ni Pt) have yielded complexes in which the borafulvenes bridge two (M(cod)) centres as a p,q2,q5 ligand; the crystal structure of one such compound is shown in Figure 11 The first dilithium compound of a 1,3-diboratabenzene dianion Boron 35 Li,[B(Bu')CHB(Bu')C(SiMe,)C(SiMe,)C HI was cleanly prepared by reducing a nido-tetracarbahexaborane with Li in thf.' 2f The reaction was reversible and oxidation back to the tetracarbahexaborane was achieved by boiling the 1,3-diboratabenzene dianion in 1,2-dibromoethane.A related benzo-tetracarbahexaborane derivative reacted with [CpCo(C,H,),] to form a 1,3-dihydr0-1,3-diborananaphthalenecom-plex by a similar rearrangement of the ligand and displacement of ethylene.12g The barriers to rotation about B-N bonds of the 1-aminoborepins 1-(N-benzyl-N- methy1amino)borepin and l-(N-benzyl-N-methylamino)-4,5-dihydro-borepin have been determined from VT 13C NMR spectroscopy as 18 and 19.8 kcal/mol respective- ly; the corresponding rotational barriers of a variety of aminoboranes have been calculated using the semi-emperical AM 1 method.'2h The first boron bridged naphthalene has been prepared in excellent yield as a colourless crystalline solid from the reaction of Cl,BNPr' with 1,8-dilithionaphthalene.'2i 1,2,5-phosphadiborolanes have been prepared and characterized from the reactions of (2)-1,2-bis[chloro(diisopropylamino)boryl]ethane with Li,PPh and 1,2-bis[chloro(diisop- ropy1amino)boryll-1,2-diisopropyIideneethanewith LiPH,-dme; the inversion barrier at P is distinctly lower than that of related unsaturated compounds. 12j The synthesis deprotonation and ring expansion reactions of 2,3-bis(dimethylamino)-2,3-dibora-tetralin have been described'2k and the catalytic dimerization of 1,2-bis(di-isopropy1amino)-1,2-dihydr0-1,2-benzodiborete with [Pd(phthalocyanine)] led to the eight-membered tetrahydrodibenzoteraborocine (C4B4) ring with N'Pr groups on boron.' 2r Inorganic Ring Systems.-The reaction of (Et,B),O with sulfuric acid led to the crystalline cyclic sulfate EtBOB(Et)OS(O,)O whose structure has been determined by X-ray analysis; the heterocycle has also been prepared from Et,B,O on reaction with The triarylborthiins Ar,B,S (Ar = 4-MeC6H4 3-MeC6H, 2-MeC6H4 4-EtC6H, 3,5-Me,C6H,) have been prepared from the reaction of ArBBr with HgS in benzene under relfux.' 3h The substituted aryl derivatives are less air-stable than Ph,B,S and are significantly decomposed to B/O/S rings (e.g.Ar,B,S,O Ar,B,SO, and Ar,B,O,) as evidenced by mass spectrometry within minutes in air.MNDO calculations have been made on Et,B,O and Ph,B,O using both the X-ray determined and optimized geometry of these molecules.The results were compared with hypothetical 'monomeric' molecules (R-B=O) and have led to calculated energies of trimerization of ca. -200 kJ mol-'.13' The reactions of borazine with a variety of olefins (including ethylene propene 1-butene cis-and trans-2-butene 3,3,3-tri- fluoropropene styrene a-methylstyrene and 4-allylanisole) catalysed by [RhH(CO)(PPh,),] have been found to give the mono- di- and tri-B-alkyl borazines in excellent yields.' 3d The reactions of B,B',B"-trimethyl-N,N',N"-triarylborazine (aryl = Ph 4-FC,H4 and 4-MeC6H,) with [Cr(CO),] in BuO,/thf afforded com- pounds in which one aryl ring is @-bonded to a (Cr(CO),) moiety in preference to the y6-borazine ligand.'," Halide abstraction from Cl,BN(Me)PC12NPCl,N Me (struc- l3 (a) R.Koster W. Schussler D. Blaser and R. Boese Chem. Ber. 1994 127 1593; (h) M. A. Beckett P. R. Minton and 9. Werschkun J. Organomet. Chem. 1994,468,37;(c)A. Sporzynski and H. Szatylowicz,ibid. 470 31; (d) P. J. Fazen and L. G. Sneddon Organnmetallics 1994 13 2867; (e)S. Allaoud S. Conte B. Fenet B. Frange F. Robert F. Secheresse and A. Karim J. Organomet. Chem. 1994 469 59; (fl D. P. Gates R. Ziembinski A. L. Rheingold 9.S. Haggerty and I. Manners Angew. Chem. Int. Ed. Engl. 1994 33 2277; (9) 9. Kaufmann N. Metzler H. Noth and R.T. Paine Chem. Ber. 1994 127 825. M. A. Beckett Cli6i ClC2i Figure 12 Molecular structure qf the Jirst hybrid horazine-phosphazine ring [BCl(NMe)2(PCI,)2N]f as found in [BCl(NMe)2(PCl,),N][GaCl,] (Reproduced by permission from Angew.Chem. Int. Ed. Engl. 1994 33 2278) ture determined by X-ray analysis) by GaCl produced the first hybrid borazine- phosphazine ring system namely [ClBNMePCI,NPCl,N Me][GaCI,]; an X-ray crystallographic study of this compound revealed a virtually planar ring (Figure 12) with B-N bond lengths of 1.436(9) and 1.422( 10) which are similar to those found in borazines (1.43 A).13s The preparation of the Cr(CO) complex of the triphosphat- riborinane Ph,P,B,mes has been reported by reaction with [Cr(CO),(MeCN),] in acetonitrile; the complex has been characterized by NMR and by X-ray crystallogra- ~hy.',~ Multi-decker Complexes.-The photoelectron.spectra of the 30 valence electron triple -decker complexes (p-q5-C,H,B Me) [M(r5-C,H,B Me)] (M = Co Rh) have been Boron 37 R2 Ri Ri Figure 13 Iron ligand complexes of 1,4-dihydro-l,4-diboranaphthalenes (Reproduced by permission from Chem. Ber. 1994,127,1557) reported together with those of the sandwich complexes [(q5-C4H4B Me)MCp] (M = Co Rh); the reported spectra were interpreted on the basis of ab initio configuration interaction (CI)calculations carried out on model complexes involving . C,H,B H ligand~.'~" Similarly the.electronic structures of (p-C4H,B Me) [Mn(CO),] and (CXB Me)Co(p-C,H,B Me)Mn(CO) have been determined from He' PE spectra and INDO calculations in which relaxation and correlation effects have been taken into account.14' The structure and bonding of the four iron complexes shown in Figure 13 including the triple-decker complex (p-q6-C8B,H,)[FeCp] have been investigated by means of the perturbational molecular orbital theory on the basis of the Extended Hiickel calculation^.^ 4c 6 Boron-Pnictogen Species Quantum mechanical calculations predict the B-N bond length in H,NBF to be 1.68A; the previously reported experimentally determined value of 1.59A which is based on microwave spectroscopic measurements is probably too short.5a Improved syntheses of B,(NMe,), B,(NMe,), and B,(NMe,) have been reported; two of the l4 (a)I. Hyla-Kryspin R. Gleiter G. E. Herberich and M. Benard Organometallrcs 1994 13 1795; (6) R. Gleiter 1. Hyla-Kryspin and G.E.Herberich J. Organomet. Chem. 1994 478 95; (c) R. Gleiter I. Hyla-Kryspin and W. Siebert Chem. Ber. 1994 127 1557. (a) V. Jonas and G. Frenking J. Chem.SOC.,Chem. Commun. 1994,1489; (h)G. Linti D. Loderer H. Noth K. Polborn and W. Rattay Chem. Ber. 1994 127 1909; (c) D. Loderer H. Noth H. Pommerening W. Rattay and H. Schick ibid. 1605; (d) D. Dau M. Fan E.N. Duesler H. Noth and R.T. Paine Inorg. Chem. 1994 33 2151; (e) A.-C. Gaumont K. Bourumeau J.-M. Denis and P. Guenot. J. Organomet. Chem.,1994,484,9;0s.Moreton Znorg. Chim. Actu 1994,215,67;(g)T.J. Groshens and C. E. Johnson J. Organornet. Chem. 1994,480 11; (h)R. Kniep G. Gozel B. Eisenmann C. RGhr M. Asbrand and M. Kizilyalli Angew. Chem. Int. Ed. Engl. 1994 33 749. 38 M. A.Beckett terminal dimethylamino groups can be replaced by halogen to yield the qwdihalides B,(NMe,),X (X = Cl Br I) which could be further substituted at X by groups such as RO RS RHN R,P and R.'5b trans-Amination reactions of B,(NMe,) with secondary amines led to mixed tetraaminodiborane(4) compounds e.g. B,(NMe,) -,,(NR,),; B,(NC,H,,) has been characterized by an X-ray diffraction study which revealed the presence of a long B-B bond (1.75 A).' 5c Derivatives of the type R,N(Me,N)BB(NMe,)NR were more readily accessible from LiNR and B,(NMe,),Cl .' 5c Diborylphosphanes of the general formula RBClPHBR', have been prepared from the reaction of (BuiN),BP(H)Li-DME and (Pr\N)[(Me,Si),N]- BP(H)Li.DME with tmpBC1 and (Me,Si),NBCl,; the diverse dehydrohalogenation chemistry of these molecules has been studied and products such as cyclic (B2PJ 1,3-diborylated diphosphadiboretanes and acylic diphosphadiboretanes were re- ported.'5d A stable cyclic phosphine-borane adduct Bu'PHBH,CH,CH,C H has been prepared by the chemoselective complexation of allyl-t-butylphosphine with BH followed by an intramolecular anti-Markovnikov hydroboration of the adduct.5e The complex trans-[Rh(CO)X(PEt,),] (X = Br I) reacted with PH,BCl or PH,BBr in CH,Cl at 183K to yield the oxidative-addition products [Rh(CO)XH(PH,BX,)(PEt,),].' 5f Phosphinoborane compounds of the type [R,BPR;] (R = Me Et; R' = Bu',SiMe,) have been used in chemical vapour deposition studies in attempts to prepare BP thin-films on Si substrates. However all films were deficient in P (B/P = 0.5) and contained considerable carbon (C/B = 0.67-7).'5g The BPC films obtained were chemically inert and may be of interest as protective coatings.The crystal structures of MCBPO,] (M = Ca Sr) and Ba,[BP,O,,] have been undertaken.'5h 7 Boron-Chalcogen Species Kinetics of the interchange between boric acid and tetrahydroxyborate in aqueous solution of pH 8-10 at 20-52 "C have been studied by bandshape analysis of "B NMR signals; calculated activation parameters reflect a dimeric [(HO),B(p-OH)B(OH),] -transition state."" The thermodynamics of several 1:1 and 1 :2 complexes of the borate anion with bidentate ligands (1,2-ethandiol 1,2-propandiol gycolic acid lactic acid oxalic acid) have been reported.'6b Boric acid trimethyl ester has been used as a probe molecule in an IR study of the Lewis base properties of the metal oxides MgO CaO ZrO, TiO, SnO, and Sb205.16c The new compound K,Zr(BO,), which is isoelectronic and isostructural with buetschliite has been identified from a phase study of the K-Zr borate system.'6d The solid state structure of the new borate Li,Be,B(BO,) has been determined crystallographically; the structure is a dense tangle of Li- and B-centred triangles Li- and B-centred distortion 0tetrahedra and Li centred trigonal prisms."" The coordination geometry of boron in polyoxotungstates has been studied by "B MAS NMR spectroscopy; important information on the local 16 (a)K.Ishihara A. Nagasawa K. Umemoto H. Ito and K. Saito Inorg. Chem. 1994,33,3811; (b)R.Pizer and P.J. Ricatto ibid.,2402; (c)C. Li S.-F.Fu H. Zhang and Q. Xin J. Chem.SOC.,Chem. Commun. 1994 17; (d) A. Akella and D. A. Keszler Inorg. Chem. 1994 33 1554; (e)J. L. Luce K. I. Schaffers and D. A. Kesder ibid.,2453; v) A. R.Couto C. N. TrovBo J. Rocha A.M. V. Caveleiro and J. D. Pedrosa de Jesus J. Chem. Soc. Dalton Trans. 1994 2585; (g) P. Vinatier P. Graverau M. Menetrier L. Trut and A. Levasseur Actu Crystallogr. Sect. C 1994 50 1180; (h) R. Wehmschulte K. Ruhlandt-Senge M. M. Olmstead M. A. Petrie and P. P. Power J. Chem. SOC. Dalton Trans. 1994,2113; (i) M. T. Ashby and N. A. Sheshtawy Organometallics 1994 13 236. Boron 39 R a,R = IPr b,R= BU Figure 14 Reaction of WH,Cp with RBCI (Reproduced by permission from Chem.Ber. 1994 127 1613) symmetry was revealed which was not forthcoming from other techniques.' 6f The crystal structure of Li,BS, obtained by crystallizing the corresponding glass exhibits a higher symmetry than other M,B(O,S) structures such as Li,BO or TI,BS and appears to be a new member of the M,AX group of compounds.'6g The use of bulky aryl substituent groups (mes and 2,4,6-Pr;C6H,) has allowed the structural characterization of the monomeric B-S compounds mes,B(SPh) and (2,4,6-Pr\C,H,)B(SPh),; these compounds show a short B-S distance of ca. 1.808 with close alignment between B and S p-orbitals-consistant with a n-interaction; the barrier to B-S rotation obtained by variable temperature NMR studies is 18.4 and 12 kcalmol- ' respectively.'6h The barrier to rotation about the B-X bonds of coordinatively unsaturated borates and thioborates have been discussed.The lower rotational barrier in the 0 derivatives is attributed to a greater stabilization of the transition state and therefore rotational barriers do not reflect the relative strengths of the B=O and B=S n-bonds.16' 8 Boron Halide Species Quantum mechanical calculations at the MP2/TZ2P level of theory have predicted geometries and bond energies of donor-acceptor complexes of the Lewis acids BF, BCI, BH, AICI, and SO which are in good agreement with experimental gas-phase values.' 70 The zwitterions [CpWH,(q5-C,H,BRC1,)] (R = Pr' But) with exocyclic boron substituents have been isolated in 60% yield from the reactions of [CpWH,] with the Lewis acids Pr'BCl and Bu'BC1 (Figure 14); the structure of the But derivative has been determined crystallographically' 7b The dialkyl chloroborane BCIR [R = CH(SiMe,),] reacted with [NEt,][M(CN)(CO),] (M = Cr Mo W) in CH,Cl or PhMe and gave the thermally stable complexes [M(CO),(CNBR,)].The Cr derivative has a linear M-C-N-B skeleton (X-ray) consistent with the zwitterionic formulation [(CO),Cr -CN+BR,].' 7c (a)V. Jonas G. Frenking and M. T. Reetz J. Am. Chem. SOC.,1994,116,8741; (b)H. Braunschweig and T. Wagner Chem. Ber. 1994,127,1613; (c)G.Beck M. F. Lappert and P. B. Hitchcock J. Organomet. Chem. 1994,468 143.

ISSN:0260-1818    

DOI:10.1039/IC9949100019

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

4 Aluminium Gallium Indium and Thallium BY J. P. MAHER School of Chemistry University of Bristol Bristol BS8 1 TS UK The computer search of the literature for papers related to the chemistry of the title elements has taken the same form as previous years this year yielding just over 4000 references slightly more than for 1993. The proportion of papers abstracted element by element was 71% aluminium 14% gallium 10% indium and 5% thallium. Only a very small amount of this work is reported here the great bulk of chemical applications being ignored. However some applications are very striking none more so than the initial reports from SAGE (the Russian American Gallium Solar Neutrino Experi- ment) where a huge pool (57 tons!) of liquid gallium is being used to trap solar neutrinos to test solar models.’ There has also been a great deal of current interest in the preparation and properties of ‘ITO’ (indium-tin-oxide) films.2 The future always seems to be around the corner for GaAs semiconductors despite many favourable report^,^ though there are numerous methods for producing GaAs and the other related Group 3-5 materials and thin films.4 An interesting new catalytic system for fixing carbon dioxide has been based upon a rare earth phosphonate and triisobutylaluminium catalyst this catalyses the formation of a copolymer with epichlorohydrin.s 1 OrganometallicHighlights Organometallic studies dominate current Group 13 chemical research for gallium and indium this probably has a good deal to do with the aforementioned interest in Group 3-5 materials.This year there were as many references to gallanes and indanes as there were to alanes. Compounds which contain aluminium in various ring systems have been prepared and characterized by spectroscopy or by X-ray diffraction. The compound [Me2M(p2- C,H,S)] (M = Al In) has a four-membered Al,S,-ring Me,Al(p-Me)(p2-‘ 0. L. Anosov et al. Philos. Trans. R. SOC.London A 15,346 1994; also J. N. Abdurashitov Phys. Lett. B 1994 328 234. ’ D. Gallagher F. Scanlan R. Houriet H.J. Mathieu and T.A. Ring J. Mater. Res. 1993 8 3135. J. Travis Science 1993 262 1819. V. Lakhotia J. M. Heitzinger A.H. Cowley R.A. Jones and J.G. Ekerdt Chem. Mat. 1994,6,871;M. A. Khan D.T. Olson and J.N. Kuznia Appl. Phys. Lett. 1994 65 64; M.Kitsunai and T. Yuki Appl. Organometallic Chem. 1994 8 167; D. M. Frigo G. J. M. Veneijden P. J. Reuvers and C. J. Smit Chem. Mater. 1994 6 190; B. Fraser L. Brandt W.K. Stovall H.D. Kaesz S.I. Khan and F. Maury J. Organomet. Chem. 1994 472 317; A.C. Jones J. Auld S.A. Rushworth and G. W. Critchlow J. Cryst. Growth 1994,135,285;S. R. Aubuchon A.T. Mcphail R. L. Wells J. A. Giambra and J. R. Bowser Chem. Mater. 1994 6 82. Z. Q. Shen X. H. Chen and Y.F. Zhang Macromol. Chem. Phys. 1994 195 2003. 41 J.P. Maher C,H,S)AlMe an A1,CS-ring and ((2-C,H3s),A1[p-N(H)C(H)(C6H5),]) ,an Al,N,- ring.6A very unusual Zr-A1 ring with an acetylide bridging between the aluminium and the zirconium is found in the complexes Cp,Zr(p-$ :q2-RCCMe)(p-C=CR)AlMe (R = SiMe, cyclohexyl CMe, or Me); seven-membered hetero-dimetallic Al-Zr and A1-Hf cyclic frameworks showing n-agostic o-ally1 Zr and Hf interactions were also found.7 Reactions of Me,Al with 1,4-dioxa-8-azaspir0[4.5]decane in toluene gave the Al,N,-containing [Me,Al-N(CH,CH),-C-(OCH,),1,.8 A silyl-aminoalane ring is found in [(Me,Si),AlN(H)(SiMe3)]2.9 Cyclo-metallation of olefins and of acetylenes with alkylalanes in the presence of Cp,ZrCl has been shown to give 3-substituted alumina-cyclopentanes and -cyclopentenes.In [Al(CH,C(CH,NH),),(A1(CH3)2)3] both four- and six-coordinated A1 atoms have been observed with the tripodal NH groups serving as both chelating and bridging ligands. The four aluminium atoms all lie in a plane with three forming an equilateral triangle around the fourth central Al a central AlN6 unit of the complex has octahedral symmetry and the other three aluminium atoms are in a tetrahedral environment.The central A1 is connected to the terminal A1 by two bridging nitrogen atoms of the tripodal ligand forming three four-membered rings1 The compound ([(Me2A1),(p-OCH,-2-C,H,S),IAI) also contains four- and six-coordinate alumin- ium centres.' The reaction of [(Me3Si),CH],Al-CH,-Al[CH(SiMe,)2]2with LiCH(PMe,) in the presence of tmeda has been shown to lead to the formation of a five-membered AI,C,P heterocycle the crystal structure determination revealed a strongly bent ring with the P located above the plane of the Al,C so that one A1 is coordinated by the carbanionic C atom and the second one coordinated by one P atom.' Rather more common are the four-membered rings found in the neopentyl compounds [Np,AlN(H)Ph], [Np,AlSNp], and [BiphAlN(H)Ph] (Np = Me,CCH and Biph = bi~henyl).'~ The C-H acidic compounds Me,C-AIR and Me,C-CH,-AlR (R = CH(SiMe,),) have been deprotonated by treatment with LiCH(SiMe,) in the presence of 1,3,5-trimethylhexahydrotriazinane, deprotonation occurring at a methyl group of one of the element-organic substituents.The carbanions which are formed are stabilized by coordination to the unsaturated A1 atoms as four-membered heterocy~les.'~ Bu'Li has been shown to react with the recently synthesized methylene bridged dialuminium compound [R,AlCH,AlR,]2 (R = CH(SiMe,),) in the presence of tmeda by p-elimination forming a three-centre- two-electron Al-H-A1 bonded compound [R,Al(p-CH,)p-H(AlR,] .' Alanes with chain structures have been described.An N-Al-0-A1-N linkage has been found in the aluminoxane [(2-C,H,S),Al.N(Me,)CH2CsH4FeCp]20 which was formed from the reaction of (2-C4H,S),A1.0Et with the hydrated H. Rahbarnoohi R. Kumar M. J. Heeg and J. P. Oliver Organometallics 1994 13 3300. ' G. Erker M. Albrecht C. Kruger M. Nolte and S. Werner Organornetallics 1993,12,4979;G. Erker R. Noe and D. Wingbermuhle Chem. Ber. 1994 127 805. J. B. Hill T. A. Talley W.T. Pennington and G. H. Robinson J. Chem. Crystall. 1994 24 61. J. F. Janik E. N. Duesler and R.T. Paine Chern. Ber. 1993 126 2649. lo U. M. Dzhemilev and A. G. Ibragimov J. Organornet. Chem. 1994 466,l.M. D. Li C. C. Chang S.T. Liu G. H. Lee Y. Wang and S. M. Peng Organometallics 1994 13 1504. R. Kumar V. S. J. Demel M. L. Sierra D.G. Hendershot and J. P. Oliver Organometallics 1994,13,2079. l3 W. Uhl and M. Koch Z. Anorg. Allg. Chem. 1994 620 1427. l4 M. D. B. Dillingham S. J. Schauer J. Byershill W. H. Pennington and G. H. Robinson J. Coord. Chem. 1994 31 283. l5 W. Uhl M. Koch S. Pohl and W. Saak Z. Anorg. Allg. Chem. 1994 620 1619. W. Uhl and M. Layh 2. Anorg. Allg. Chem. 1994 620 856. Aluminium Gallium Indium and Thallium 43 amine.' Under mild conditions Al-A1 bonded tetrakis[bis(trimethylsilyl)methyl] dialane reacts with Et,P+Te- to give R,AlTeAlR (R = CH(SiMe,),) in high yields." In the case of [RMe,AlClAlMe,R]Li (R = 2,3,4,5-tetramethyl pyrrole anion) two Me,RAl units are bridged by the chlorine atom and both pyrrole rings are pentahaptocoordinated to the lithium atom.' The tridentate amine ligand Et,NCH,CH,NHCH,CH,NEt (tetraethyldiethylenetriamine tedtaH) reacts with Me,Al in the appropriate ratios to give either AlMe,(tedta) or Al,Me,(tedta) the A1 being coordinated to the central N or to all three nitrogen atoms respectively." No evidence for n-interactions in Al-N or Ga-N bonds has been found from a study using 'H and 13C NMR and X-ray crystallographic analyses of the compounds mes*GaCl(N(H)Ph}.O.25(hexane),mes;GaN(H)Ph mesA1(N(SiMe3),}, mes*Ga (NHPh), and ClGa(N(SiMe,),} (mes = 2,4,6-Me,C6H, mes* = 2,3,6-Bu',C6H2).The data suggest that any n-interactions in the M-N bonds are rather weak and are of the order of 40 kJ mol- ' The reactions of MgCp with an RZA1C1 compound offer a convenient route to the corresponding Cp2AlR species this method has been used to prepare Cp,AlMe(l) and Cp,AlEt (2).The 'H NMR spectrum of the diethyl ether adduct Cp,AlMe.Et,O (3) provided evidence for small amounts of the ligand redistribution species CpAlMe and Cp3A1.,' When (1) or (3) were reacted with Bu'NC in petroleum ether the ligand redistribution product Cp,Al(C=NBu') (4) precipitated selectively from solution.Cp,Al complexes such as (4) and the isomeric adduct Cp,Al(N=CBu') can be prepared more directly in higher yields from AlCl and MgCp,. An X-ray crystal structural analysis of (4) showed it to be a monomer with C symmetry and the cyclopentadienyl rings coordinated in an q' fashion to the aluminium.* In contrast the decamethyl-aluminocenium ion [AlCpz] +,is a n-stabilized cation with an q5-bonding c~nfiguration.'~ ab initio SCF Calculations of the structural and NMR parameters of this newly discovered aluminocene sandwich complex and of the corresponding bis(q5-dicarbollide)aluminium anion are in good agreement with the experimental data.24 Other interesting alanes are [A1,(p3-8-quinolylimide),(CH3)7(p-OCH,)],formed by oxygen-induced structural transformation of the polynuclear organoaluminium complex [A14(p3-8-quinolylimide),(CH3)8];25the first carbon-phosphorus-alumin-ium cage compounds formed by cyclo-oligomerization of phosphaalkynes with trialkylaluminium compounds;26 and an isolable 'Al"' species (bipy)Al[CH(SiMe,),] which has been characterized unambiguously by EPR and UV-visible spectroscopy and by cyclic voltammetry as an Al"' complex of the bipy radical anion." " R.Kumar H. Rahbarnoohi M. H. Heeg D.G. Dick and J. P. Oliver Inorg. Chern. 1994 33 1103. W. Uhl and U. Schutz Z. Naturforsch. Teil B 1994 49 931. l9 H.D. Hausen J. Todtmann and J. Weidlein J. Organornet. Chem. 1994 466 C1. 2o S.J. Trepanier and S.N. Wang Organometallics 1994 13 2213. " P. J. Brothers R. J. Wehmschulte M.M. Olmstead K. Ruhlandtsenge S. R. Parkin and P. P. Power Organometallics 1994 13 2792. 22 J.D. Fisher M.Y. Wei R. Willett and P.J. Shapiro Organometallics 1994 13 3324. " C. Dohmeier H. Schnockel C. Robl U. Schneider and R. Ahlrichs Anyew.Chem. Int. Ed. Engl. 1993,32 1655. 24 U. Schneider and R. Ahlrichs Chem. Phys. Lett. 1994 226 491. 25 S.J. Trepanier and S.N. Wang Angew. Chem. Int. Ed. Engl. 1994 33 1265. 26 B. Breit A. Hoffmann U. Bergstrasser L. Ricard F. Mathey,and M. Regitz Angew. Chem. Int. Ed. Engl. 1994 33 1491. '' S. Hasenzahl W. Kaim and T. Stahl fnorg. Chim. Acta 1994 225 23. 44 J.P. Maher The first alane-phosphine adduct with C,P,-pentacoordination at aluminium has been described namely Al[o-(Ph,PCH,)C,H,] ,. Trigonal bipyramidal coordination at Al is obtained by two of the anionic phosphines acting as chelating ligands spanning equatorial C-atoms and axial site P-atoms while the third phosphine is only C-bonded. The heavier congeners with Ga In and TI are stereochemically non-rigid molecules in solution.In the solid state the indium complex also has the same C,P,-pentacoordination whereas the gallium and thallium compounds have four- coordinate metal centres (C,P). These observations may be rationalized by assuming less polar Ga-P bonds as compared to AI-P and In-P bonds whilst in TlL the ligand bite is insufficient for either five- or six-coordination.28 As with aluminium there has been a great deal of research carried out on cyclic gallium and indium compounds. Thus dimeric and trimeric 1-(dialky1amino)- 1 -galla-3-cyclopentenes [(C,H6)Ga(NR,)] (x = 2,3) and dimeric 3,4-dimethyl derivatives [(2,3-Me2C,H,)Ga(NR,)] have been obtained.29 The first gallacyclopentane [(CH,),Ga-p-AsBu',], has been synthesized.,' Various intramolecularly-stabilized gallium- and indium-organyls have been described namely (CH,),Ga(CH,),NMe, (CH,),GaCH,CHCH,CH,NNMe, and (C,F,)21n(CH,),NMe,;31 a large group of 5-methyl- 1 -galla(inda)-5-azacyclooctanes; and bis[ 3 -(dial ky1amino)propyll gal- lium tris [3- (dialk y1amino)propyll gallium and tris [3- (dialk y1amino)prop y1)indium derivative^.^ The dimer [Me,GaN(Si(H)Me,),] has been prepared from the reaction of Me,Ga with 1,1,3,3-tetramethyldisilazanein toluene the dimer crystal structure was determined.The compounds [Cy,GaNHPh], [Cy,GaNHBu'], and (tetramethyl-piperidine)GaCl feature short Ga-H-N distances of 2.1 13 A 2.33 A and 2.28(9) 8 re~pectively.~~ The compound mes,BN(Bu')GaEt is monomeric with trigonal planar coordinated gallium nitrogen and boron atoms.The B-N bond length is short (1.384(6)A) the Ga-N bond length is rather long (1.937(3) A) although the nitrogen is non-bridging.,' X-Ray structure determinations of the pyrrole derivatives Me,GaC,H,NMe and Me,InNC,Me show two formula units per cell forming 'n-dimers' via short intermolecular M-C contacts of 2.481 8 and 2.575 8 respective-iy.36 The monomeric low coordinate indium amides Bu~InN(2,6-Pr~C,H,)SiPh3 and In(N(SiMe,),} have been characterized by X-ray crystallography. Both have planar coordination at In and N with In-N bond lengths of 2.104(3)A and 2.049(1)8 respectively. These lengths are relatively short in comparison to the sum of atomic radii of indium and nitrogen. This shortening may be accounted for in terms of an ionic contribution to the In-N bond rather than by the presence of significant In-N p-p n-'' G.Muller and J. Lachmann Z. Naturforsch. Teil B 1993 48 1544. 29 G.E. Herberich U. Englert and D. Posselt J. Organomet. Chem. 1993 461 21. 30 A. H. Cowley S. Corbelin R.A. Jones R. J. Lagow and J. W. Nail J. Organornet. Chem. 1994,464 C1. '' H. Schumann 0.Just T. D. Seuss F. H. Gorlitz and R. Weimann J. Organomet. Chem. 1994 466 5. '' H. Schumann 0.Just T. D. Seuss and R. Weimann J. Organomet. Chem. 1994 472 15. 33 H. Schumann T. D. Seuss 0.Just R. Weirnann H. Hemling and F. H. Gorlitz J. Organomet. Chem. 1994 479 171. 34 D.A. Atwood V. 0.Atwood D. F. Carriker,A. H. Cowley F. P. Gabbai R. A. Jones M. R. Bond and C. J. Carrano J. Organomet. Chem.1993 463 29. 35 G. Linti J. Oryunomet. Chem. 1994,465 79. 36 J. Todtmann. W. Schwarz J. Weidlein and A. Haaland Z. Naturforsch. Teil B 1993 48 1437. Aluminium Gallium Indium and Thallium 45 bonding.37 The first example of a monomeric bis(amino)gallane with a gallium-silicon bond (tmp),GaSi(SiMe,) (tmp = 2,2,6,6-tetramethylpiperidino) has a crystal struc- ture containing a trigonal planar coordinated gallium atom with long Ga-N and Ga-Si bonds of 1.918 and 2.47A re~pectively.~~ New phosphinogallanes [Me,GaP(SiMe3),],39 and indanes [Me,InPPh,]340 have been described. In the former which is sterically crowded the Ga-P distance was determined to be 2.456(1)8, in the latter trimer where both In and P have distorted tetrahedral coordination the mean In-P bond distance is 2.62(1)A while the corresponding mean In-C distance is 2.17(1) A.[Ga{ p-PH(Bu'))Bu\)], bis(p-t-buty1phosphido)-bis(di-t-butylgallium),contains an almost planar Ga,P ring with average Ga-P bond lengths of 2.478,.,' In-As bonds have been found to occur in the dimer [R,InAs(SiMe,),] and the mixed bridge compound R,InAs(SiMe,),InR,C1,42 and R,InAs(SiMe,) (R = Me3CCH,).43 The reactivity of organogallium peroxides towards phosphines phosphites and triphenylarsine has been The syntheses and molecular structures of the dialkyl-aluminium and -gallium ~tannoxides,~' and of diphenyl-gallium and -indium ~tannanethiolates,~have been described. Some mixed transition-metal Group 13 compounds have been synthesized and examined. The compounds (q5-Cp)(CO),FeGa(Bu') (5) {(q'-Cp)(CO),Fe),GaBu' (6) and (q5-Cp)(CO),FeGa(But)2(q'-Cp)(CO),Fe), (7) have been synthesized.The average Fe-Ga distances in (5) and (6) are 2.413(4) and 2.411(5) 8,respectively and in (7)the Fe-Ga distance is slightly lengthened to 2.441(1) A. These distances and the IR carbonyl spectra suggest that any n-interaction between the iron and the gallium p-orbital is probably very weak.47 The In-Mo distances 4.0401(5) and 4.0703(5) A and the large In-S-Mo angles indicate no interaction between the two different metal centres in indium(II1) thiolate-bridged molybdenocene complexes [InCl {MoCp,(p-SEt),),][BPh,] .48 Novel stable and volatile organoindium transition metal com- plexes of the type [L(CO),)M],[InR,-,(D)] (M = Mo W Mn Re Fe Co Ni; L = q'-Cp CO; R = CH,SiMe, (CH,),NMe,; D = 0,N donor; n = 1-4; a = 1,2) have been prepared in high yields.49 The reaction of Ar*GaCI with Na[Mn(CO),] in Et,O solution produces a mixed crystal of the first reported digalloxane [Ga(Ar*){Mn(CO),)],O and [Ga(Ar*)(CI){Mn(CO),f] (Ar* = ~,~,~-Bu',C,H,).~' The compounds (C,Me,H),GaCI Ga(C,Me,H) and Ga(C,Me,) have been 37 M.A.Petrie K. Ruhlandtsenge H. Hope and P. P. Power Bull. Soc. Chim. Fr. 1993 130 851. 38 R. Frey G. Linti and K. Polborn Chem. Ber. 1994 127 101. 39 M. D. B. Dillingham J. A. Burns J. Byershill K. D. Gripper W. T. Pennington and G. H. Robinson Inorg. Chim. Acta 1994 216 267. 40 J.A. Burns M. D.B. Dillingham J. B. Hill K. D. Gripper W.T. Pennington and G. H. Robinson Organometallics 1994 13 1514.41 K. Kirschbaum and D. M. Giolando Acta Crystallogr. Sect. C 1994 50 1244. 42 L. J. Jones A. T. Mcphail and R. L. Wells Organometallics 1994 13 3634. 43 M. F. Self A. T. Mcphail L. J. Jones and R. L. Wells Polyhedron 1994 13 625. 44 M. B. Power J. W. Ziller and A. R. Barron Organometallics 1993 12 4908. 45 S.U. Ghazi R. Kumar M. J. Heeg and J. P. Oliver Inorg. Chem. 1994 33 411. " S. U. Ghazi M. J. Heeg and J. P. Oliver Inorg. Chem. 1994 33 4517. 47 X. M. He R.A. Bartlett and P. P. Power Organometallics 1994 13 548. 48 M.A. A. F. D. Carrondo A. R. Dias M. H. Garcia P. Matias M. F. M. Piedade and M. J. V. Debrito J. Organornet. Chem. 1994,466 159. 49 R. A. Fischer E. Herdtweck and T. Priermeier Inorg. Chem. 1994 33 934. 5o A.H.Cowley A. Decken C.A. Olazabal and N.C. Norman Inorg. Chem. 1994 53 3343. 46 J.P. Maher prepared. The latter exists as discrete molecules with all C5Me5 rings q’-bonded to Ga with an average C-Ga distance of 2.037 A metastable solution of GaCl has been shown to react with LiCp or MgCp compounds to form several new cyclopentadienyl- gallium(1) species GaCp* GaCpBu‘ GaCp((SiMe,),) and Ga(cp(B~),).’~ (vide supra A1 cyclopentadienide corn pound^.^^-^^} The new organogallium(1) compound [Ga(CH,CMe,)] has been prepared by the reduction of Ga(CH,CMe,),Cl using either sodium or lithium with naphthalene in thf. The [Ga(CH,CMe,)] probably exists as a mixture of species which are gallium cages containing from 6 to 12 gallium atoms.’ Weak arene-thallium interactions have been observed in the covalent thallium(1)-nitrogen compound [2,6-Pr\C6H,(Me,Si)NTl]4.54 Dimethyl(diphenylphosphinothioato)thallium(m) shows a polymeric structure that can be regarded as a folded ribbon formed by supramolecular association of four-membered TlSOP chelate rings connected through inter-unit dative 0 -+ T1 bonds (Tl-0 = 2.509(7)A) and T1-S secondary interactions (TI-S = 3.402(3)A).Overall the thallium atoms are six-coordinate in a severely distorted octahedral geometry.” The crystal structure of dimethyl(di-n-propy1dithiocarbamato)thal-lium(II1) [TlMe,(S,CNPr2)] has been determined. The thallium atom is coordinated to the two sulfur atoms of a slightly anisotropic bidentate dithiocarbamate ligand and to the two methyl groups which form a highly distorted tetrahedral environment.In the crystal lattice these units are linked by additional weak T1-S interaction^.^^ A new type of stable polymetallic chain compound involving Tl”’ and containing a B-T1-transition metal bond sequence [(rn-H2C,B,,H,)T1(Cl)M(CO),] which is analogous to the B-carboranyl-Hg” derivatives has been formed by the reaction of NaM(CO) (M = Mn Re) with TlCl in thf.57 2 Hydrides Apart from boron none of Group 13 form an extensive series of hydrides recent reviews have described the current state of research.58 Matrix isolation studies in solid argon have been applied to the preparation and study of aluminium gallium and indium di- and tri-hydrides vibrational frequencies and force constant data were disc~ssed.’~ The reaction of equimolar amounts of AlH,NMe and M(CH,SiMe,) (M = Zr Hf) in benzene lead to the exchange of all three Al-H bonds for Al-CH,SiMe bonds and the isolation of Al(CH,SiMe,),NMe,;60 Al(CH,Ph),NMe has been produced from Zr(CH,Ph),.The reaction of H,MNMe, M = A1 or Ga with Hfacac has been shown to cause metallation and reduction (for 51 H. Schumann S. Nickel and R. Weimann J. Organomet. Chem. 1994 468,43. 52 D. Loos and H. Schnockel J. Organomet. Chem. 1993 463 37. 53 0.T. Beachley J. C. Pazik and M. J. Noble Organometallics 1994 13 2885. 54 S. D. Waezsada T. Belgardt M. Noltemeyer and H. W. Roesky Angew. Chem. Int. Ed. Engl. 1994,33 1351. 55 J. S. Casas A. Castineiras 1. Haiduc A. Sanchez J. Sordo and E. M. Vazquezlopez Polyhedron 1994,13 1805.56 J. S. Casas M. V. Castano C. Freire A. Sanchez J. Sordo E. E. Castellano and J. Zukermanschpector Inorg. Chim. Acta 1994 216 15. 51 A.Y. Usyatinskii G.Z. Suleimanov E.A. Zulfugarly V.A. Antonovich V.I. Bregadze and I. P. Beletskaya Russ. Chem. Bull. 1993 42 554. 58 A. J. Downs and C. R. Pulham Chem.SOC.Rev. 1994,23,175; C. L. Raston J. Organomet. Chem. 1994,475 15. 59 P. Pullumbi C. Mijoule L. Manceron and Y. Bouteiller Chem. Phys. 1994 185 13; ibid. 1994 185 25. 60 W.G. Feighery R. U. Kirss C. H. Lake and M. R. Churchill Inorg. Chim. Acta 1994 218 47. Aluminium Gallium Indium and Thallium 47 aluminium) or only reduction (for gallium) of the b-diketone both products are binuclear species [Al {OC(CF )=CHCH (CF )0)(NMe ),I and (R ,R ,S/S,S,R)dia-stereoisomer and [Ga,{rac-OCH(CF,)CH,CH(CF,)O) ,(NMe,),] containing five- or four-coordinate metal centres respectively.61 Bis(diethy1amino)aluminium hydride and lithium tris(dihexy1amino)aluminium hydride have been shown to be much weaker reducing agents than lithium aluminium hydride for a wide variety of organic substrates showing some interesting specific reductions., 3 Metal-Metal Bonded Compounds A novel thallium compound Na,K,,Tl,, containing isolated T1:- and T1;- units has been prepared in high yield by fusion of the elements in sealed Ta containers followed by slow cooling and annealing at 250 “C.The crystal structure shows two T1 units and one Tl unit ordered in layers and well separated by the cations which bond to and bridge between faces edges and vertices of the clusters.The T1 is a distorted trigonal bipyramid the new Tl geometry with (TI-TI) = 3.13-3.44.& can be obtained by substantial elongation of two side edges of a tricapped trigonal prism so that the intervening face-capping atom moves close to that face and becomes eight-b~nded.~~ An alloy previously described in the phase diagram of barium and gallium as ‘BaGa’ has turned out to be containing isolated octahedral Ga clusters which are surrounded by a cuboctahedron of twelve Ba atoms. Application of Wade’s rules to the Ga naked cluster gives an excess of two electrons per formula There have been two reports of materials containing TI-T1 bonds. Tetrakis (hypersily1)dithallium has been described as a divalent thallium c~mpound,~’ and [MeSi(Bu‘NTl),] an amide of tris-(t-buty1amino)methylsilaneas a centrosymmetric dimer held together by TI-T1 bonds.66 In solid thallium(1)-bis(trimethylsilyl)amide cyclic dimers have been shown to be linked to infinite chains by intermolecular T1-TI contacts.67 The anion [R,AlAlR,Br]- (R = CH(SiMe,),) with an aluminium-aluminium and a terminal aluminium-bromine bond has been reported to be formed when A1-A1 bonded [R,AlAlR,] reacts with LiBr in n-pentane in the presence of tmeda.The crystal structure determination shows that the A1-A1 bond length is not significantly different (2.643A) from that in the starting material whereas the Al-Br bond is rather long (2.476A) indicating a weak coordinative bonding.68 The sterically highly shielded bases bis(trimethylsilyl)methyllithiumor bis(dimethylphosphany1)methyllithium react with [R,AlAlR,] to yield under deprotonation of a methyl group a carbanionic species which is stabilized by an interaction with one of the coordinatively unsaturated A1 atoms.With the former base a five-membered heterocycle Al,SiC, is formed the Al-A1 bond remaining uncleaved and the A1-A1 bond length only slightly changed in 61 J. L. Atwood F.C. Lee C. L. Raston and K. D. Robinson J. Chem. SOC.,Dalton Trans. 1994 13 2019. J. S. Cha 0.0.Kwon and J. M. Kim,.Bull. Korean Chem. SOC.,1994,15 132; J. S. Cha 0.0.Kwon and J.C. Lee ibid. 1993 14 743. 63 Z.C. Dong and J. D. Corbett J. Am. Chem. Soc. 1994 116 3429. 64 M.L. Fonasini and M. Pani J.Alloys Comps. 1994 205 179. 65 S. Henkel K. W. Klinkhammer and W. Schwarz Angew. Chem. Int. Ed. Engl. 1994 33 681. 66 M. Veith A. Spaniol J. Pohlmann F. Gross and V. Hunch Chem. Ber. 1993 126 2625. 67 K. W. Klinkhammer and S. Henkel J. Organomet. Chem. 1994 480 167. 68 W. Uhl U. Schutz S. Pohl and W. Saak Z. Naturjorsch. Teil B 1994 49 637. 48 J. P. Maher comparison to the neutral starting compound.69 It was previously observed that [R,AIAIR,] reacts with potassium in 1,2-dimethoxyethane to form the surprisingly stable radical monoanion [R,AIAIR,] * -[K(dme),] + ;however longer reaction times of some days at room temperature and with an excess of potassium give complete decomposition with cleavage of ether molecules and formation of several new products such as R,A1(Me)OC,H40MeK(dme) and R,A1(OC,H,0Me)2K.70 The digallane (tmp),GaGa(tmp),) is a pale yellow solid with a Ga-Ga bond length of 2.525(1)81 and its two-GaN unit twisted by 31" against each other.71 Several new (transition metal)-Group 13 metal cluster compounds have been prepared and characterized.The compound [(Cp*)ZrF,] reacts with AIMe to form a zirconium-aluminium-carbon cluster .72 The intermetallic derivatives [((2,6-Me2-NCH,),C,H,)M(Co(CO),),] (M = Ga In) have been prepared. The crystal struc- tures reveal that only one of the dimethylamine groups is coordinated to Ga so that the CGaCo moiety is pyramidal and the indium compounds has a distorted-trigonal- bipyramidal geometry containing a planar CInCo unit.73 The aqua cluster [Mo (p3-S)(p-0)(p-S),(H,0),14f reacts with indium metal in aqueous solution to give a novel sandwich cubane-type molybdenum-indium mixed-metal cluster [(H,0)9Mo,S,01nOS3Mo,(H20)9]8+ which is oxidized in hydrochloric acid back to the starting material via an intermediate tentatively assigned as [Mo31n(p3-S)(p-O)(p- S)2]:aii.74 Novel types of adducts of nickel carbonyl clusters with indium halides have been synthesized and subsequently characterized by X-ray diffraction.[NEt,] [Ni,(p3-InBr,)(y2-p6-In,Br,)(CO) JMe,CO has an octahedral Ni core capped on two adjacent faces by an In,Br moiety and on a third face opposite to one of the above by an InBr molecule. In [NEt,],[Ni,(y2-pu6-In,Br~),(CO) ,]-Me,CO two In2Br moieties are found to cap two opposite pairs of adjacent triangular faces of the Ni,octahedron.In both anions the remaining triangular faces of the octahedron are capped respectively by five and four face-bridging carbonyl groups whereas each nickel atom binds a terminal carbonyl ligand. The compound [NEt4],[Ni,,(p6- In)(y2-p6-In,Br,(OH)(CO)22)] has been shown to derive from two distinct Ni,(CO),(p2-CO) units sandwiching a unique bare indium atom and bridged by an In,Br4(p2-OH) moiety.75 Finally [(CO),CrTlCr(CO),] - the first complex reported as containing linear twofold-coordinated thallium(i) has been de~cribed.~ 4 Coordination Chemistry The coordination chemistry of aluminium has been reviewed in a recent book which has considered aspects of aqueous coordination chemistry low valent and paramag- netic compounds the chemistry of alkoxides thiolates and the heavier group 16 derivatives of aluminium (and gallium).77 h9 W.Uhl H. H. Karsch U. Schutz and A. Vester Chem. Ber. 1993 126 2637. 70 W. Uhl A. Vester D. Fenske and G. Baum J. Organomet. Chem. 1994 464 23. '' G. Linti R. Frey and M. Schmidt Z.Naturforsch. Teil 8,1994 49 958. " A. Herzog H. W. Roesky Z. Zak and M. Noltemeyer Angew. Chem. Int. Ed. Engl. 1994 33 967, -'C. A. Olazabal F. P. Gabbai A. H. Cowley C. J. Carrano L. M. Mokry and M. R. Bond Orgunometallics 1994 13 42 1. 74 F.G. Sakane Y.G. Yao and T. Shibahara. Inorg. Chim. Actu 1994 216 13. 75 D. E. Martin M.C. Iapalucci and G. Longoni lnorg. Chern. 1993 32 5536. 76 B. Schiemenz and G. Huttner Angew. Chem. lnt. Ed. Engl.1993 32 1772. 77 'Coordination Chemistry of Aluminium' cd. G. H. Robinson VCH New York 1993. Aluminium Gallium Indium and Thallium 49 Unusual coordination geometries have been observed for azaaluminatranes. The compound Al(Me,SiNCH,CH,),N has been shown to contain a trigonal mono- pyramidal aluminium centre and the dimeric azaaluminatrane [Al(Me,SiNCH,CH,),(HNCH2CH2)N]2 possesses an unusual cis-configuration of the central four-membered ring the aluminium atoms displaying a distorted trigonal bipyramidal coordination geometry.78 The related new monomeric azagallatranes Ga(RNCH,CH,),N (R = SiMe, SiMe,Bu') and dimeric azagallatrane [Ga(MeNCH ,CH ,),N] ,have been prepared. There have been further studies on the intriguing tri-radical species Ga(3,6-dbsq) and A1(3,6-dbsq) (dbsq = 3,6-di-t-butyl-l,2-~emiquinonate).EPR spectra recorded on these in a toluene glass at 77 K show signals at g values of 2,4 and 6 indicative of an S = 3/2 ground state. At lower temperatures magnetic measurements show evidence for an S = 3/2 ferromagnetically coupled ground state. The mixed-charge ligand complex (Ga(tmeda)(3,6-dbsq)(3,6-dbcat)shows no band that may be assigned as an interligand intervalence- transfer transition. 8o Di-radical compounds in the indium (111) halide-3,Sdi- t- but yl-o- benzosemiquinone system have also been characterized. Other interesting Group 13 complexes have been prepared. With [(en),M"'(OH),] ligands (M = Cr Co) heteronuclear complexes are formed with AlI'' Ga"' In"' and Tl"' in aqueous solution in all cases the [(en),M"'(OH),] groups act as hydroxo- bridged bidentate ligands.82 Indium(m) complexes of poly(pyrazoly1)borate ligands have been de~cribed,~ as have a series of thallium(1n) porphyrin complexes.84 5 Bioinorganic Chemistry Soil acidification has been shown to lead to increased ratios of absorption by plants of A13+ instead of Ca2+ and Mg2'+ausing in particular inhibitions in Mg2'- regulated biochemical processes which lead in turn to stunted tree With the above in mind the bioinorganic chemistry of A13+ has been reviewed,86 as has possible A13+neurotoxicity in acid rain.87 The determination of 26A1/27Al-ratios in biological materials with an accuracy of ca.2% is now possible by means of accelerator mass spectrometry (AMS).Thus 26A1can be used as a tracer to determine A1 content and distribution within complex chemical and biological systems and to investigate the kinetics and mechanisms of Al-transport pathways.88 Using AMS the aluminium distribution between the major cell compart- ments of human neuroblastoma cells grown in culture has been determined. Whilst 26A1 was retained by the nuclear proteins and nuclear sap 26A1 did not appear to bind " J. Pinkas T. K. Wang R. A. Jacobson and J.G. Verkade Inorg. Chem. 1994 33 4202. 79 J. Pinkas T. L. Wang R. A. Jacobson and J.G. Verkade Inorg. Chem. 1994 33 5244. " C.W. Lange B.J. Conklin and C.G. Pierpont Inorg. Chem. 1994 33 1276. 81 T. A. Annan M. A. Brown A. Elhadad B. R. McGarvey A. Ozarowski and D. G. Tuck Inorg.Chim. Acta. 1994 225 207. 82 F. Rominger A. Muller and U. Thewalt Chem. Ber. 1994 127 797. 83 D. L. Reger S. S. Mason A. L. Rheingold and R. L. Ostrander Inorg. Chem. 1994,33 1803; D. L. Reger S. S. Mason L. B. Regfer A. L. Rheingold and R. L. Ostrander ibid. 1994 33 181 1. x4 M.O. Senge K. Ruhlandtsenge K. J. Regli and K. M. Smith J. Chem. SOC.,Dalton Trans. 1993 3519; M.O. Senge ibid. 1993 3539. 85 W. Kaim and B. Schwederski 'Bioinorganic Chemistry Inorganic Elements in the Chemistry of Life' Wiley Chichester 1994. R6 Z. Kovarova Chem. Listy 1994 88 32. 87 R.B. Martin Acc. Chem. Res. 1994 27 204. " J. P. Day et al. Nuclear Instrum. Methods Phys. Res. Sect. B 1994 92 463. 50 J. P.Maher to the nucleic acids.89 With AMS it was found that for a young rat population 26Al-retention in the liver was seven times that in the brain.90 Also at the ANTARES AMS Centre the medical applications of 26A1 to measure aluminium concentrations in blood serum and in urine have been used so that aluminium resorption factors and rate constants for resorption elimination and exchange between the compartments have been obtained.” The biological availability of aluminium in mixed-ligand media of biological interest has been investigated by means of aluminium inhibition of hexokinase activity in ~itro.~~ Interactions and complexes between A13 + and various biochemicals have been studied including adenosine 5’-tripho~phate,~~ and the effects of aluminium ions on the dephosphorylation of phosvitin catalysed by acid pho~phatase.~~ Ternary complex formation has been studied in the A13+/AMP ADP ATP/oxalic acid lactic acid malic acid systems.Under physiological conditions at micromolar A13+ concentrations and at high ligand excess the aluminium is bound mainly to the nucleotides almost exclusively in the presence of oxalic and lactic acids and about 30% in the presence of malic acid.95 Radiolabelled 67Ga and ‘In-troponate complexes are now routinely used in medicine for tumour diagnosis and for radioimmunotherapy .8 There have been several structural- and solution-studies of complexes relating to this interest.96 The increased use of Group 3-5 semiconductors will increase the possibility of these materials entering the environment and so increased human animal and plant exposure with very uncertain consequences will occur thus it is important that their possible toxicological effects are examined.97 The same caveat is necessary for thallium should there ever be widespread use of thallium-based superconductor materials.98 Despite much chemical research there is scant data on the content and behaviour of thallium in soils and plank9’ 6 Miscellaneous This section highlights various other aspects of Group 13 chemistry not covered in previous sections.A novel microporous layered aluminophosphate (A1 :P = 0.75) in which there are two distinct kinds of eight-membered ring within the layers has been prepared 89 S.J. King et al. ibid. 1994 92 469. 90 D. Fink et al. ibid. 1994 92 473. 91 C. Hohl et al.ibid. 1994 92 478. 92 C. Exley N.C. Price and J.D. Birchall J. lnorg. Biochem. 1994,54 297. 93 I. Dellavia J. Blixt C. Dupressoir and C. Detellier Inorg. Chem. 1994 33 2823. 94 T. P. Geladopoulos and T. G. Sotiroudis J. Inorg Biochem. 1994,54 247. 95 T. Kiss I. Sovago R.B. Martin and J. Pursiainen J. lnorg. Biochem. 1994 55 53. 96 E. Cole R. C. B. Copley J.A. K. Howard D. Parker G. Ferguson J. F. Gallagher B. Kaitner A. Harrison and L. Royle J. Chem. SOC.,Dalton Trans. 1994,1619; F. Nepveu F. Jasanada and L. Walz Inorg. Chim. Acta 1994,215,237; I. Abrahams,N. Choi K. Henrick H. Joyce R. W. Matthews M. Mcpartlin F. Brady and S. L. Waters Polyhedron 1994,13,513; J. E. Bollinger J. T. Mague and D. M. Roundhill lnorg. Chem. 1994 33 1241. Y. Aoki M.M. Lipsky and B. A. Fowler Appl. Organomet. Chem. 1994,8,253;A. Tanaka A. Hisanaga M. Hirata M. Omura N. Inoue and N. Ishinishi Appl. Organomet. Chem. 1994 8 265. 98 R. J. G. Sobott Neues Jahrbuch Fur Mineralogie 1993 166 77. 99 V. Jovic ibid. 1993 166 43. Aluminium Gallium Indium and Thallium [A1,P40 6] [NH,(CH,),NH,][C,H oNH,] .loo The compound [CH,NH,] [Ga (PO,),OH] has a zeolite-like hydroxygalliophosphate framework containing Ga in both tetrahedral and fivefold coordination.' O' The first three-dimensional frame- work cobalt-gallium phosphate [C,H,NH][CoGa,P,O,,] has been described the three-dimensional structure is unique; large pores in the structure hold the pyridinium cations. lo2 The trimer Ga has been observed and characterized from its EPR spectrum in a frozen matrix.'03 Indium amides (III(NH)~), Li,In(NH,), Na,In(NH,)( +x) K,In(NH,)( +x) and indium nitride have been obtained as well as the new ternary nitride Li,InN,.'04 The coordination geometry about the indium in trichlorobis(tetrahydro-furan)indium(m) approximates to a trigonal bipyramid with three Cl atoms in equatorial positions and two axial tetrahydrofuran ligands.'05 The compound (PPh,),Pt,(p3-S),InC13 represents the first report of a square-based pyramidal structure of a five-coordinated adduct of InX3.lo6 The anions [In,SCl6I2 - [In,SBr612- [In,S,C16]3- [In,Se,C16]3- and [Ga,S,C16]3- are the first known chalcogenohalogeno anions of Main Group 13 elements.The first two anions consist of two InSX tetrahedra sharing a common sulfur atom.The frameworks of the remaining three anions each contain a six-membered ring of alternating metal and chalcogen atoms. Two terminal chlorine atoms complete a distorted tetrahedral coordination sphere around each metal atom.107 (PPh,),[In(S,)(S,)Cl] contains anions with trigonal-bipyramidal coordination of In with C1 occupying an axial position and the S and s6 groups being bonded in a chelate manner. In (PPh,),[In(S,)Cl,] the anion has a distorted trigonal-bipyramidal coordination of In atoms the S group occupying one axial and one equatorial position.'08 A new indium telluride [Bu:N],In,Te, has been synthesized by the cathodic dissolution of an In,Te alloy electrode at room temperature in a 1,2-diaminoethane solution of [Bu:N]I.The structure consists of one-dimensional (In,Te,) -chains isotypic to the chains found in the SiS and KFeS structure types.'09 Similarly the cathodic dissolution of Ga,Te gave [Ph,P][GaTe,(en),] the structure of which consists of one-dimensional [GaTe,(en),] chains held together by NH-Te hydrogen bonds.' The properties of thallium-based superconductors have been reviewed,' ' this comprehensive reference deals with just about every aspect of their chemistry including safety aspects of their use. The average valence of thallium in high-T loo R. H. Jones A. M. Chippindale S. Natarajan and J. M. Thomas J. Chem.SOC.,Chem. Commun. 1994,565. lo' F.P. Glasser R.A. Howie and Q.B. Kan Acta Crystallogr. Sect. C 1994 50,848. ln2 A.M. Chippindale and R.I. Walton J.Chem. SOC.,Chem. Commun. 1994 2453. J.A. Howard H. A. Joly and B. Mile J. Chem. Phys. 1994 100 3369. '04 A. P. Purdy Inorg. Chem. 1994 33 282. B. R. Whittlesey and I. P. Ittycheriah Acta Crystallogr. Sect. C 1994 50 693. M. S. Zhou Y. Xu C. F. Lam P. H. Leung L. L. Koh K. F. Mok and T. S. A. Hor Inorg. Chem. 1994,33 1572. lo' B. Krebs W. Bobb H. J. Wellmer and K. Wiesmann 2. Anorg. Allg. Chem. 1994 620 1234. lo' W. Bubenheim and U. Muller Z. Anorg. Allg. Chem. 1994 620 1607. C. J. Warren S. S. Dhingra R.C. Haushalter and A. B. Bocarsly J. Solid State Chem. 1994 112 340. C.J. Warren D. M. Ho R.C. Haushalter and A. B. Bocarsly J. Chem. SOC.,Chem. Commun. 1994,361. l1 'Thallium Based High Temperature Superconductors' ed. A. L. Hermann J. V. Yakhmi Marcel Dekker New York 1994.J. P. Maher T1-Ba-Ca-Cu-0 superconductors has been determined by capillary-tube isotacho- phoresis giving a value of 2.93-2.97.'12 MOCVD methods have been used to prepare phase-pure epitaxial T1,Ba,Ca2Cu,010 thin films (T,= 115OK) on single crystal LaAlO substrates using Ba(hfa),.tet Ca(Hfacac),.tet and Cu(Hfacac) (tet = tetraglyme); thallium was then incorporated into the films via Tl,O,.' l3 A new superconductor T1,~,Hg,~,Ba,Ca2Cu3O,,,, has been synthesized with a T,of 130OK. The possibility of substituting mercury for thallium in the 2223 cuprate was demonstrated.' l4 Another new mercury-thallium-based superconductor with a T of 132OK namely [Hg,~,Tl,.,Ba,(Ca -xSr,),CuO,O +J has been described." Thallium minerak are rare in nature and require due to their low temperature stabilities special physico-chemical conditions for their formation; mineral para- geneses for a wide range of sulfur-based minerals has been described.' l6 K.Watanabe K. Demura and K. Fueki Bull. Chem. SOC.Jpn. 1994 67 1024. B. J. Hinds D. L. Schulz D. A. Neumayer B. Han T.J. Marks Y. Y. Wang V. P. Dravid J. L. Schindler T. P. Hogan and C. R.Kannewurf Appl. Phys. Lett. 1994 65 231. 'l4 F. Goutenoire A. Maignan G.Vantendeloo C.Martin C. Michel M. Hervieu and B. Raveau Solid State Commun. 1994,90,47. N. H. Hur N. H. Kim K. W. Lee Y. K. Park and J. C. Park Muter Res. Bull. 1994 29 959. M. A. Elhaddad and G. H. Moh Neues Jahrbuch Fur Minerdogie 1993 166 9.

ISSN:0260-1818    

DOI:10.1039/IC9949100041

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

5 Carbon Silicon Germanium Tin and Lead By D.A. ARMITAGE Department of Chemistry King's College Strand London WC2R 2LS UK This review covers the literature for 1994. The construction of carbon networks using polyynes is highlighted' with the longest chains of carbon atoms connecting two transition metals prepared to date resulting from the oxidative coupling of Cp*Re(NO)(PPh,)(C-C),-H (1 :n = 1,2) using Cu(OAc) to give Cp*Re(NO)(PPh,)C,(NO)(PPh,)ReCp*,(n = 4,6,8). The chirality at Re and two closely spaced sets of resonances in the NMR spectra support the presence of meso and ( & ) diastereoisomers. The UV maxima shift to longer wavelengths with increasing chain length and the cation radicals become less stable with increasing n.' The lithium derivative of (1 :n = 2) adds to the CO of ~S-Cl,C,Mn(CO)3 to ultimately form the cation (2) in which a five carbon cumulene unit connects the two Re atoms (Equation 1).The cumulene form appears to dominate over the polyyne form since the Re-C stretching frequency is at ca. 1700cm-' compared with that of 1653-1630cm-' for Re-C-C. The first isolable pentatetraenylidene complex (3) has been formed from the reaction of (Ph,PCH2CH2PPh,),RuC12 and HC-C-C-C-CPh,OSiMe (Equation 2) and has C=C bond lengths of 125 130 124 and 136pm therefore indicating some triple-single alternation superimposed on what are essentially double bonds.4 Noble metal carbonyl cations are highlighted5 and the two complexes [Ag(CO),] '[B(OTeF,),]-(n = 1,2) have been isolated and characterized under an atmosphere of CO.The carbonyl stretching frequencies of 2204cm-' (n = 1) and 2196cm-' (n= 2) and a long Ag-C bond indicate little back-donation. The C-0 bond distances of 107-109 pm are distinctly shorter than in gaseous CO (1 12.8 pm) and it is suggested that coordination may occur with an orbitaI of antibonding character that coordina- tion increases s-character in the C-0 bond and that coordination to an electrophilic site strengthens the C-0 bond.' It has been shown that the 1:2 anionic Pd complexes resulting from sulfur and seleno derivatives of 1,3-dithiole-2-thionate C3Sz -and C,S,Sei -(L) can be readily oxidized to (Me,N)+(PdL,)-. The anions occur as dimers with Pd-Pd distances of U.H. F. Bunz Angew. Chem. Int. Ed. Engl. 1994 33 1073.' M. Brady W. Weng and J.A. Gladysz J. Chem. SOC.,Chem. Commun. 1994 2655. W. Weng T. Bartik and J.A. Gladysz Angew. Chem. Int. Ed. Engl. 1994 33 2199. D. Touchard P. Haquette A. Daridor L. Toupet and P.H. Dixneuf J. Am. Chem. SOC.,1994,116,ll 157. L. Weber Angew. Chem. Int. Ed. Engl. 1994 33 1077. P.K. Hurlburt,J. L. Rack J. S. Luck S. F. Dec J. D. Webb 0.P. Anderson and S. H. Strauss J. Am. Chem. Soc. 1994 116 10003. 53 D.A. Armitage ON 9".PPh3 ON'??-PPh, C fi Ill c C -fi q5-C15C5Mn(C0)3 5 BF3 Cp*Re(NO)(PPh3)C4Li E Me30*BF4-L2RuCh + H(CZC)2-CPh20SiMe3 (' Et3N* [L~(CI)RU=C=C=C=C=CP~-JPF~-(2) (ii) Ph3C*PF6-(L = PhZPCH2CH2PPh2) (3) 317-318 pm. The conductivity of these complexes increases with pressure but decreases at low temperat~re.~ The metallocarbohedrene v&,+,has been shown to react with oxygen to give V,C:o and CO.It is much more reactive than Ti,C12 which has a nearly closed shell electronic structure.8 Further structural work on the paramagnetic anions M:-(M = Ge Pb) (21 skeletal-electrons) has shown that they possess the tricapped trigonal prism structure expected for 20 skeletal-electron systems rather than the monocapped quadratic antiprism found for 22 skeletal-electrons. The tin derivative possesses D, symmetry whilst the germanium and lead ones are distorted to C2v.9Previous work supports these conclusions." By way of contrast the phase Na,Sn contains isolated tin atoms (inter-tin distance 554pm) and reacts with both red and white phosphorus to give Na,P and Sni- while with NbCl, water-stable Nb,Sn results.' ' Cleaving one Si-Si bond of (Ar2Si)3 (Ar = 2-Me,NCH2C,H,) with Li in 1,4- dioxane gives the trisilane dianion Li(Ar,Si),Li which gives two 29Si NMR signals at -26.5 and -31.8.Dioxane and the amino groups coordinate to Li and Li-Si bonds of 254.3 pm are the shortest reported to date. Steric crowding lengthens the Si-Si bonds to 240.4 pm while the Si-Si-Si angle is 136.9'. Li(Ar,Si),Li results from the reaction with excess lithium and is the first vicinal dilithiodisilane. The structure indicates two ' C. Faulmann J.-P. Legros P. Cassoux J. Cornelissen L. Brossard M. Inokuchi H. Tajima and M. Tokumoto J. Chem. SOC. Dalton Trans. 1994 249. * C.S. Yeh S. Afzaal S.A. Lee Y.G. Byun and B.S.Freiser J. Am. Chem. SOC. 1994 116 8806. T. F. Fassler and M. Hunziker Znorg. Chem. 1994 33 5380. lo S. C. Critchlow and J. D. Corbett J.Am. Chem. SOC.,1983,105,5715; C. Belin H. Mercier and V. Angilella New. J. Chem. 1991,15 931. F. Guerin and D. Richeson J. Chem. SOC.,Chem. Commun. 1994 2213. Carbon Silicon Germanium Tin and Lead independent molecules with Si-Si bonds of about 238 pm and Si-Li bonds of about 255 and 259 pm." The first reported synthesis of disilagermirane (Me,Si),Ge[Si(SiMe,),1, has resulted from the reaction of (Me,Si),SiLi(THF) and GeCl,. The exocyclic Ge-Si bonds of 235.6 pm are shorter than the endocylic distances of 239.1 pm and a similar shortening is also observed with the Si-Si bonds. Reacting (Me,Si),Ge with MeLi in the presence of 12-crown-4 gives [Li( 12-crown-4)J +[Ge(SiMe,),] -with Si-Ge bonds of 236.6 and 236.9pm and bond angles of 100.5 to 102.7".13 The thermolysis of mes,SiGe or mes,Ge with 2,3-dimethylbutadiene has been shown to give the germacyclopentenes (4) and (5).It is thought that germylene addition may occur with (5) giving germasilene or digermene rearrangement the appropriate silyl or germyl germylene (Equation 3). l4 (4) (5)(M = Si Ge) rnes2M=Gemes2 -mes,M(mes)Ge (3) (M = Si Ge) Photolysis of (BukSi) in the presence of alkenes and dienes has been shown to result in disilene and silyene addition to the double bond to give the silirane and 1,2-disilacyclobutane respectively (Equation 4) while with conjugated dienes the 2-vinylsilirane is formed.' H 77 + Bu,'Si + A k'R H-C-C-R !' But2Si-/\ CH2 But2Si-SiBut2 (4) With the bis(alky1idene)disilacyclobutane (6) photolysis in the presence of C, gives the 1 1adduct through addition to the C-C bonds common to two adjacent hexagons.Subsequent rearrangement leads to the 2,6-disilabicyclo[4.2.O]oct-1-ene derivative (7) (Equation 5).16 Photolysis of C, and the disilirane (8) results in addition only at the equatorial C-C bonds without rearrangement to give the 1,3-disila substituted cyclopentane (9) (Equation The disilene silicon atoms of fully silylated disilenes have been found to show significant downfield shifts from unsilylated derivatives. Also dissolution of the l2 J. Belzner U. Dehnert and D. Stalke Angew.Chem. Int. Ed. Engl. 1994 33 2450. l3 A. Heine and D. Stalke Angew. Chem. Int. Ed. Engl. 1994 33 113. l4 K. M. Baines J. A. Cooke C. E. Dixon H. W. Liu and M. R. Netherton Organometallics 1994 13 631. l5 M. Weidenbruck E. Kroke H. Marsmann S. Pohl and W. Saak J. Chem. Soc. Chem. Commun. 1994 1233. l6 T. Kusukawa Y. Kabe T. Erata B. Nestler and W. Ando Organometallics 1994 13 4186. l7 T. Akasaka E. Mitsuhida W. Ando K. Kobayashi and S. Nagase J. Am. Chem. SOC.,1994 116,2627. D.A. Armitage disilenes in hexane produces a colour change (R,Si = PriSi) from yellow to red indicating conformational changes due to the relief of steric strain.18 The hindered diplumbane TsiMe,PbPbMe,Tsi has the longest PbPb bond reported to date (296.8 pm) shows considerable tetrahedral distortion at lead is orange-yellow in colour and dissociates photochemically to give plumbyl radicals through PbPb cleavage.' Cleavage of the bridging Si-Si bond of decaisopropylbicyclo[2.2.0]hexasilane using PdCl,(PhCN) has been shown to give both cis-and trans-1,4-dichlorocyclo-hexasilanes.Their structures indicate a sterically distorted chair conformation while reduction with sodium reforms the bicylco[2.2.0]hexasilane quantitatively.20 The ladder polysilane (1 0) results from all-transCBu'ClSi] and C1-PriSiSiPriCl using Li. The Si-Si bond lengths vary from 241.2 to 248.1 pm.21 Cage-opening of octakis( 1,1,2- trimethylpropyl)octasilacubane using PCI gives a mixture of the endo,exo- exo,exo- and endo,endo-isomers of 4,s-dichloroocta- kis(l,1,2-trimethylpropyl)tetracyclo[3.3.O.O2~7.O3~6] -octasilane (1 la and 1 lb), (note the structural rearrangement on cleavage of the one Si-Si bond).Activation of silane by tungsten cations in the gas-phase has been found to result in M. Kira T. Maruyama C. Kabuto K. Ebata,and H. Sakurai Angew. Chem. Int. Ed. Engl. 1994,33 1489. l9 S. M. Whittaker F. Cervantes-Lee and K. H. Pannell Inorg. Chem. 1994 33 6406. *' S.Kyushin H. Yamaguchi T. Okayasu Y. Yagihashi H. Matsumoto and M. Goto Chem.Lett. 1994,221. S. Kyushin M. Kawabata Y. Yagihashi H. Matsumoto and M. Goto Chern. Lett. 1994 997. 22 M. Unno K. Higuchi M. Ida H. Shioyama S. Kyushin and H. Matsumoto Organometallics 1994 13 4633. Carbon Silicon Germanium Tin and Lead 57 dehydrogenation and the formation of cluster species such as WSi,,H (x= 4,6).’ Reacting sodium or potassium with silane in diglyme gives the polysilylated silyl anion Mf[SiH3 -,,(SiH,),,] -which itself can be methylated or silylated using p-tolylS0,Me or C,F,SO ,SiH,.Similarly the silylated germane stannane or phosphine result if GeH, SnH, or PH are reacted with silane. Neopentasilane (H,Si),Si has Si-Si bond lengths of 233.2 Also sodium has been shown to cleave the terminal C-0 bond of diglyme to yield the silanide Na,(OC2H,0C,H,Me),(SiH,),. The Na cube is face-capped by alkoxide ions with the two silanide anions bonding to opposite sodium ions remarkably through bridging hydrogen atoms from the H,Si-group and not through silicon coordination. Calculations show this inverted coordination to be energetically the more favo~rable.~~ The gas-phase structure of H,Si-GeH has been shown to comprise Si-H and Ge-H bonds of 149.4 and 153.8pm respectively while the Si-Ge bond length of 236.4pm was found to be shorter than calculated.26 2,6-bis(Dimethylaminomethyl)phenyl-lithium(LLi)reacts with its 1-silylderivative to give the [4 + 41-coordinated silicon species (12).The H-Si-H angle is about 115” with an Si-N bond length trans to Si-H of 311.7pm and those trans to Si-C of 289.5pm. The amino groups are equivalent on the NMR time-scale. With Ph,C+BF or iodine (12)is deprotonated to give the five-coordinate monocation (13)with one of the substituted aryl groups non-coordinating. With HCl or HBr hydrogen is evolved to give the six-coordinate cation (14) (Scheme l).27 LLi + LSiH3 -1 2 ph37 (12) 0.512 1.1 I /N\ Scheme I The six-coordinate bis[8-dimethylaminonaphthyl]dihydrosilane (15) has been deprotonated with iodine to give the five-coordinate cation stabilized by the centrosymmetric 1;-anion.This cation has apical Si-N bonds of 207 pm shorter than 23 A. Ferhati T. B. McMahon and G. Ohanessian Bull. SOC. Chim. Fr. 1993 130 3. 24 T. Lobreyer W. Sundermeyer and H. Oberhamrner Chem. Ber. 1994 127 2111. 25 H. Pritzkow T. Lobreyer,W. Sundermeyer,N. J. R. van Eikema Hommes and P. von R. Schleyer,Angew. Chem. Int. Ed. Engl. 1994 33 216. 26 H. Oberhamrner T. Lobreyer and W. Sundermeyer J. Mol. Struct. 1994 323 125. ” F. Carre C. Chuit R. J.P.Corriu A. Mehdi and C. Reye Angew. Chem. Int. Ed. En& 1994,33 1097. @$+ 58 D. A. Armitage in (19,and with 8-(dimethylamino)naphthyl-lithium(L'Li) gives the seven-coordinate silane (16) (Equation 7).,* 1' QIMe2 1 LSiH2 Si-H 2 b2-(15) The first silylene complex of nickel (18) has been found to result from the stable silylene (17) and Ni(CO) (Equation 8). It is highly air- and moisture-sensitive but thermally stable [m.p. 160 "C (decomp.)] and shows approximate tetrahedral coor- dination at Ni. The Ni-Si bond lengths are ca. 221 pm and the carbonyl stretching frequencies similar to those found in (Ph,P),Ni(C0),.29 (17) (18) Photolysing Fe(CO) with (Me,N),SiH gives the silylene complex stabilized by coordinated Me,NH.Reaction with Pt(C,H,)(PR,) (19) results in displacement of both Me,NH and C2H4 to give the silylene derivative n-complexed to Pt (20) (Equation 9). (C0)4 hvlhexane YMe2 (19) p Fe(CO) + HSi(NMe,) 7(C0)4Fe=Si(NMe2)2 -i -Pf(PR3)Z (9) ,Si Me2N NMe2 The reaction of (EtO),PFe(CO) results in EtO/Me,N exchange between the phosphite and aminosilane to give [(Me,N),P(OEt)](CO),Fe=Si[( + NHMe,)-(OEt),(NMe,)] which crystallizes as a dimer through hydrogen-bonding of the coordinated amine to the ethoxy group on the silicon of the neighbouring molecule.30 Silylene complexes of transition metals have been prepared with groups at silicon capable of n-stabilization. With the ruthenium derivatives Cp*(Me,P),Ru-Si(S-p- + tolyl) and [Cp*(Me,P),Ru=Si(SEt),] BPhi exchange of thio groups occurs 28 C.Breliere F. Carre R. Corriu and M. W.C. Man J. Chem. Soc. Chem. Commun. 1994 2333. l9 M. Denk R. K. Hayashi and R. West J. Chem. SOC.,Chem. Commun. 1994 33. 30 U. Bodensieck P. Braunstein W. Deck T. Faure M. Knorr and C. Stern Angew. Chem. Int. Ed. Engl. 1994 33 2440. Carbon Silicon Germanium Tin and Lead 59 between Si sites.,' The triflates Cp*(Me,P),Ru-SiR,OTf (R = Me Ph) have been shown to react with LiB(C,F,) to give the stable silylene complexes base-free and without x-donor stabilization. The methyl derivative [Cp*(Me,P),Ru=SiMe,] + [B(C,F5),] -has a Ru=Si bond length of 223.8 pm the shortest reported to date., The silylene (17) has been shown to react with Me,SiN3 to give the silanimine which adds further azide.With the hindered Ph,CN, however the silanimine (21) can be isolated as a THF complex with a Si=N bond similar in length to that reported in Me,Si(THF)=NSiBu\ (Equation BU' The germylene (22) reacts with Me,Si(N,) to give the germanimine (23) (Ge=N 170.4 pm) which rearranges to the silanimine. This subsequently dimerizes or hydrolyses to the silatetrazole (24) (Scheme 2).34 With R2Si(N3)2 (R = But mes) 2 moles of (22) gave the bis(germanimine) R,Si(N=GeDis,),. For R = mes the Ge=N bond length is 168.1 pm and the Si-N bond 171.7pm supporting a germanimine structure. For R = But the germanimine rearranges photolytically probably through C-H insertion and butene elimination to give the cyclic silanimine (25) (Equation 11).35 Dis2Ge + Me2Si(N3)2-Me2Si-N=GeDis,/I;@-Me2Si=N-GeDis, I I N3 (23) (22) Dis = CH(SiMe,) Y3 ,GeDis2 OH Me2 1 Me2 Si Me2Si-N I1 Dis2Ge-HNSiN,' NGeDis2 N-SiMe2 N=N'IN~ Dis2Ge' N3 (24) Scheme 2 Matrix isolation spectroscopy involving the decomposition of silyl azide has provided proof of the formation of silane nitrile H-Si-N and silane imine H,Si=NH together with hydrogen loss.The dissociation enthalpy of H3N -+ SiH is estimated to be 97 & lOkJrn01-'.~~ 31 S.K. Grumbine and T.D. Tilley J. Am. Chem. Soc. 1994 116 6951. 32 S.K. Grumbine and T. D. Tilley J. Am. Chem. Soc. 1994 116 5495. 33 M. Denk R. K. Hayashi and R. West J. Am. Chem. Soc. 1994 116 10813. 34 T. Ohtaki and W. Ando Chem. Lett. 1994 1061. 35 W. Ando T. Ohtaki and Y.Kabe Organometallics 1994 13 434. 36 G. Maier and J. Glatthaar Angew. Chem. Int. Ed. Engl. 1994,33,473; R.T. Conlin D. Laakso and P. Marshall Organometallics 1994 13 838. D.A. Armitage But hv>monrn HN Ge. -2(22) + ButzSi(N,) -R,Si(N=GeDis,) ,Si=N ,Dis (11) I Dis,Ge LSiA:iMe3 Me (25) An NMR study of lithium hexamethyldisilazide with THF and ether in toluene and pentane shows that ligand exchange in the disolvated dimers proceeds by a dissociative process via monosolvated dimer~.,~ A similar study using LiN(SiMe,),/KN(SiMe,) mixtures suggests a statistical mixture of the dimers in THF but no mixed derivative in TMEDA. * The lithium dimer complexes with fluorobenzene and o-difluorobenzene to give 1 1 adducts with Li-F bond lengths of 186.6 and 189.4pm.With 1,4- difluorobenzene a linear polymer results with a Li-F bond length of 199.9 pm. In all cases the Li,N ring is maintained without Si-F cleavage.39 A range of silylated lithium amides has been structurally characterized. The tripodal amide MeC{CH,N(Li[LJ)SiMe,) (L = THF HMPTA) possesses a six-membered Li,N ring with a chair conformation which is solvated at each lithium atom.40 The compounds (Me,Si),NSi(H)(NLiSiMe,) and Me,Si(NLiSiMe,) occur as dimers in both solid and solution while lithiated derivatives of (Me,SiNH),SiH give mono- di- and tri-lithio species in solution. The tri-lithio derivative is dimeric in the solid with two interconnected SiN,Li rings.41 The hydrazine (Me,Si),N,Li is also dimeric with a chair-like N,Li ring (26) with Li-Li 228 pm N-Si 171-177 pm and N-N bonds of 150.9 pm.The compound Bu'Me,SiN(Li)-N(Li)SiMe,Bu' is a trimer which comprises two-chair Li,N rings with alternating Li and N atoms. These chairs are joined through the N-N bonds and various Li-N interactions; structure (27) represents the monomer unit.42 The thallium amide (Me,Si),NTl was shown to be monomeric in benzene and the gaseous-state but occurs as cyclic dimers in the solid-state interconnected to give infinite chains through interdimer TI-T1 contacts of 395pm some 30 pm longer than the intradimer Tl-Tl contacts.43 The silyl substituted arylamine derivative (2,6- Pr;C,H,(Me,Si)NTl) is tetrameric in the solid state with aryl groups giving $-coordination to the T1 of the neighbouring molecule and weak Tl-.Tl interactions at 406pm .44 37 B.L. Lucht and D. B. Collum J. Am. Chem. Soc. 1994 116 6009. 38 M. A. Nichols D. Waldmuller and P.G. Williard J. Am. Chem. Soc. 1994 116 1153. 39 P.G. Williard and Q.-Y. Liu J. Org. Chem. 1994 59 1596. 40 K. W. Hellmann L.H. Gade W.-S. Li and M.McPartlin Inorg. Chem. 1994 33 5974. 41 M. Veith M. Zimmer and P. Kosse Chem. Bet-. 1994,127,2099;P. Kosse E. Popowski M. Veith and V. Huch ihid. 2103. 42 N. Metzler H. Noth and H. Sachdev Angew. Chem. Int. Ed. Engl. 1994 33 1746. 43 K. W. Klinkhammer and S. Henkel 1.Organomet. Chem. 1994 480 167. 44 S.D. Waezsada T. Belgardt M. Noltemeyer and H.W. Roesky Angew. Chem. Int. Ed. Engl. 1994 33 1351. Carbon Silicon Germanium Tin and Lead 61 The silatrane ClSi(HNCH,CH,),N has been pentafluorophenylated at Si using C,F,Li but with ClSi(MeNCH,CH,),N the fluoro derivative is formed with a Si-F bond length of 164.3 pm and Si-N interaction of 203.4 pm.The pentafluorophenyl derivative is also formed which itself gives the product formed through tetrafluoroben- zyne insertion into one Si-NMe bond.45 The disilylphosphide anion of [(H,Si),P] -[Li(TMEDA),] shows a Si-P bond + length of 217 pm and an angle at phosphorus of 92.3'. With the magnesium derivative [(Me,Si) P] ,MgDME which results from [(Me,Si),N] Mg and (Me,Si),PH the Si-P-Si angle was found to be 106.6' and the Si-P bond length about 222~m.~~ Condensing Bu'SiFCl with CyPHLi gives the fluoro-substituted cyclosilaphos- phane (28) which with further CyPHLi forms the propellane-like silacyclophosphane (29) (Equation 12) in which the Si-P bond lengths are from 226 to 229 pm.The Si-.Si distance of 251.8 pm is within the range of single bonds but calculations support a Si-Si bond order of -0.260 or antib~nding.~~ Even shorter 'non-bonded' interactions are found in cyclodisiloxanes. CY CyPHLi Bu'SiFCh -Bu'FSi,/p\/SiFBu' -(12) P CY But Condensing TipBu'SiCl (Tip = 2,4,6-Pr',C6H,) with LiAsH,DME gives the first reported diarsanylsilane (30) which on lithiation and coupling with mesBu'GeF, gives the 1,3-diarsa-2-sila-4-germacyclobutane (31) and subsequently the Bu'/Bu' exo-endo bicycloCl.1 .O]butane derivative (32) as the only isomer on mercury substitution and photolysis.The compound (31) has Si-As bond lengths of 239-240 pm and Ge-As bonds of about 245.5pm (Equation 13).48 The stannaphosphene Tip,Sn-Pmes* (mes* = 2,4,6-Bu',C6H,) adds to various But J" 45 Y. Wan and J. G. Verkade. Organometallics 1994 13 4164. 46 G. Becker B. Eschbach D. Kashammer and 0. Mundt Z. Anory. Ally. Chem. 1994 620 29; M. Westerhausen and W. Schwarz ibid. 304. 47 M. Driess R.Gleiter R.Janoschek H. Pritzkow and M. Reisgys Angew. Chem. Int. Ed. Engl. 1994,33. 1484. 48 M. Dreiss and H. Pritzkow Chem. Ber. 1994 127 477. 62 D. A. Armitage a-ethylene aldehydes and ketones to give the six-membered ring stannoxaphos- phorinenes through [2 + 41 cycloaddition (Equation 14).49 0+ QCH2 Tip2Sn=Pmes* i G-C (14) R’ R2 The greater acidity of silanols compared with alcohols has long been recognized but their Bronsted basicity has been little studied.Treating Bu‘,Si+[Br,CB ,H,] -with undried solvents gives the hydrated cation- or protonated silanol[Bu’,SiOH,] . The + structure reveals hydrogen bonding between water and two bromine atoms of the anion trigonal flattening at silicon with a C-Si-C bond angle of 116” and a long Si-0 bond of 177.9pm.” Procedures have been outlined for the preparation from chlorosilanes of silanols and silane diols prone to self-conden~ation,~ while (PhCH,),SiOH (PhCH,),COH and (PhCH,),SiH are isomorphous with threefold symmetry.’ Ph,Si(OH) and Cp,MMe (M = Zr Hf) yield the eight-membered ring [Cp2M(,u- OSiPh,O)] while metallasiloxanes containing Ta Nb Mo W Re Mn and Mo have been prepared from the diols Bu\Si(OH), O(Bu‘,SiOH), and O(Ph,SiOH),.A similar oxovanadyl(1v) derivative has also been made from O(SiPh,OLi) .2THF and VCl,.’ Condensing RSi(OH) (R = 2,6-Pr\C,H3NSiMe,) with Bu\AlH furnishes the ahminosilicate frameworks Al,Si,O and A1,Si2O, and with Ti(OPr’) the Si4Ti408 framework.’ (c-C,H,Si),O,(OH) condenses with M[N(SiMe,),] (M = Y Nd) to give associated derivatives that form dimers upon coordination with Ph,PO.’ (c-C,H ,Si),O,(OH) has been capped with the Ph,C,Ti residue through reaction with (Ph,C,),TiCl in the presence of base.’ (c-C,H lSi),O comprises two non-planar Si,O rings joined cofacially by three Si-0-Si bridges to build a framework with Si40 ringss7 The structures of several cyclodisiloxanes with mesityl and adamantyl substituents show Si-0 bonds of 167-168 pm and Si-Si cross-ring interactions of about 239 ~m.’~ Me,NLi ring-opens (Me,SiO) to give the hexameric [LiOSiMe,(NMe,)] as a hexagonal barrel of alternate Li and 0 atoms with silylamino groups coordinated to each lithium atom., Amorphous silica with oxalic acid in the presence of tertiary 49 A.Kandri-Rodi H. Ranaivonjatovo and J. Escudie Organometallics 1994 13 2787. 50 Z. Xie R. Bau and C.A. Reed J. Chem. SOC. Chem. Commun. 1994 2519. 51 J. A. Cella and J.C. Carpenter J. Organomet. Chem. 1994 480 23. 52 P. Lightfoot C. Glidewell and P.G. Bruce J. Organomet. Chem. 1994 466 51; C. Glidewell and P. Lightfoot ibid. 1994 484,175. 53 E.Samuel J. F. Harrod M. J. McGlinchey C. Cabestaing and F. Robert Znorg. Chem. 1994,33 1292; H.-J. Gosink H. W. Roesky H.-G. Schmidt M. Noltemeyer E. Inner and R. Herbst-Irmer Organometal-lies 1994 13 3420; M. Motevalli D. Shah S. A. A. Shah and A.C. Sullivan ibid. 4109. 54 M. L. Montero I. Uson and H. W. Roesky Angew. Chem. Znt. Ed. Engl. 1994,33,2103;N. Winkhofer A. Voigt H. Dorn H. W. Roesky A. Steiner D. Stalke and A. Reller ibid. 1352. 55 W. A. Herrmann R. Anwander V. Dufaud and W. Scherer Angew. Chem. Int. Ed. Engl. 1994,33,1285. 56 L.D. Field C. M. Lindall T. Maschmeyer and A.F. Masters Aust. J. Chem. 1994 47 1127. 57 H. Behbehani B. J. Brisdon M. F. Mahon and K.C. Molloy J. Organomet. Chem. 1994 469 19. 58 H. Sohn R.P. Tan D. R. Powell and R. West Organometallics 1994 13 1390.59 G. E. Herberich T.P. Spaniol and A. Fischer Chem. Ber. 1994 127 1619. Carbon Silicon Germanium Tin and Lead 63 amine and 18-crown-6 gives the soluble (R,NH+),Si(oxalate)~- in high yield providing another example of the solubilization of silica.,' The reaction of GeCl with the potassium derivative of catechol has been shown to give K2[Ge(cat),].3H,O.2EtOH as a hydrated network connected through hydrogen bonds and chains cross-linked by K-aryl 'zipper' interactions.,' Oxidizing the stannylene [2,4,6-(F,C),C6H,],Sn results in the formation of the monomeric planar cyclotristannoxane with a Sn-0-Sn angle of 135.5' and an Sn-0 bond length of 193.1 pm.62 A redetermination of the structure of lead tetraacetate shows it to be near dodecahedra1 with each acetate bidentate and Pb-0 bond lengths ranging from 224.4 to 23 1.2 The precipitate resulting from mixing cyclodextrin with lead@) nitrate shows 16 lead(I1) atoms incorporated into the cyclodextrin torus with the lone pair of electrons on lead stereo-active and the coordination around lead being composed of a square pyramid of four Pb-0 bonds., The silene Me,Si(mes)Si=C(OSiMe,)Ad adds both sulfur and selenium to give the silathiirane and silaselenirane.The former shows a Si-S bond length of 212.9 pm.65 The reaction of Tbt(Tip)SiBr with LiNaph then sulfur gives the five-membered heterocycle (33) which with Ph3P gives the silanethione (34) as yellow crystals m.p. 185-189 "C and Si-S stretching frequency of 724cm-' (Equation 15).The structure supports trigonal planar geometry at Si with an Si-S bond length of 194.8 pm some 9% shorter than a single bond and it adds to dienes mesCNO and PhNCS.66 Tbt \ (i) LiNaph Tbt \ fS-s 3Ph3P Tbt\ ,SiBr2 -,S\ I -Si=S RP (ii) sulfur Tip s's 3Ph3P=S Tip' (Tbt = 2,4 6-[(Me3Si),CHI3C6H2) The germaneselenone Tbt(mes)Ge=Se can be prepared similarly has a bond length of 218.0 pm and a stretching frequency of 382 cm-' (cf.germanethione at 521 cm- '). It reversibly adds [4 + 21 to dienes [3 + 21 to mesCNO and [2 + 21 to PhNCS.67 The macrocyclic octamethyldibenzotetraaza[ 14lannulene dianion [Me8taa12-furnishes a Sn" derivative with SnCl which adds both sulfur and selenium. The tin atom lies above the tetra-nitrogen plane with Sn-N bond lengths shorter in the oxidized chalcogen derivatives.The Sn-S and Sn-Se bond lengths are 227.4 and 239.4 pm respectively.68 Heating SnS with Rb,CO at 190 "C in the presence of H2Shas been shown to give Rb2Sn,S,.2H,O which comprises both SnS tetrahedra and SnS octahedra. The 6o K. E. Bessler and V. M. Deflon 2.Anorg. Allg. Chem. 1994,620,947. 61 J. Parr A. M. Z. Slawin J. D. Woollins and D. J. Williams Polyhedron 1994 13 3261. 62 J. F. van der Maelen Uria M. Belay F.T. Edelmann and G. M. Sheldrick Acta Crystallogr. Sect. C,1994 50,403. 63 M. Schurmann and F. Huber Acta Crystallogr. Sect. C 1994 50 1710. 64 P. Klufers and J. Schuhmacher Angew. Chem. Int. Ed. Engl. 1994 33 1863. 65 A.G. Brook R. Kumarathasan and A. J. Lough Organometallics 1994 13 424.66 H. Suzuki N. Tokitoh S. Nagase and R. Okazaki J. Am. Chern. Soc. 1994 116 11 578. 67 T. Matsumoto N. Tokitoh and R. Okazaki Angew. Chem. Int. Ed. Engl. 1994,33 2316. 68 M.C. Kuchta and G. Parkin J. Am. Chem. SOC. 1994 116 8372. D. A. Armitage reaction of SnCl and selenium with Rb,CO produces Rb,Sn,Se which contains SnSe tetrahedra and exhibits bond lengths of 246~m.~~ Fluorinating (BrMe,Si),C with SbF gives the fluoro derivative (35) which has a Catherine wheel-like structure. The c6 ring is slightly distorted to a boat structure and each Si-F bond (168pm) is longer than that for normal four- and five-coordination with the bridge bonds (239 pm) being shorter than normally found for the minimum non-bonded approach (263pm). The F-Si-F angles lie in the range 172-179" (Equation 16).At 0 "C the 29Si NMR spectrum shows the expected 1 :2 1triplet which does not change to a doublet of doublets on cooling but gives a septet at 55 "C. The 'H and I3C NMR spectra behave similarly. The septet indicates equal interactions of the Si H and C nuclei with all six fluorine atoms suggesting free rotation of the silyl groups in a cog-wheel fashion so that the fluorine atoms are transferred around the ring. This process is stopped when the ring is n-bonded to the bulky Mo(CO) residue the 29Si NMR spectrum showing only a triplet between 25 "C and 95 "C. The methoxy derivative with Si-0 bonds of 188pm has D, symmetry and gives high field 29Si NMR shifts of -64.2 ppm typical of five-c~ordination.~' F-si.-..F SbF /S@'S; 'F -(FMe,Si),C,Mo(CO) (16) Mo(C0)6 (BrMe2Si)& -Fa..Si Si \ F.....Si-F (35) Iodosilanes R,SiI have been conveniently prepared from R,SiH and Me1 using PdCl as catalyst. Yields are excellent. Et,SiI is also produced in good yields from Et,SiH and PrT7 Under microwave conditions alkyl and aryl halogermanes R,GeX,- (R = Et Bu Ph; X = C1 Br) result in good yields from the redistribution of R,Ge with GeX in a matter of minutes.72 Hydrolysis of SnF in concentrated aqueous solution gives the oxyfluoride Sn,OF,. It crystallizes with a 3D structure with both F and 0 bridges.73 The salt (NH;),Me,SnFZ-crystallizes with a hydrogen bonded network and the centrosym- metric anion has Sn-F bond lengths of 212.7 pm. The compound Et,N+Ph,SnCI has been shown to contain an anion that is trigonal bipyramidal with phenyl groups equatorial and the Sn-Cl bond lengths of 237.8 pm (equatorial) and 251.7 to 253.1 pm Stannic chloride gives a 3 :2 complex with [9]-aneS (1,4,7-trithiacyclononane) which comprises [SnC1,[9]-aneS3] + cations and SnC1;- anions in the ratio 2 :1.In the cation the thiacrown is facially coordinated while the Sn-C1 bond length of 236.9 pm is shorter than that in the octahedral anion (244.8 pm). With [18]-aneS in MeCN the adduct 2SnC1,.[18]-aneS6.MeCN results in which the thiacrown cis-chelates to SnCl h9 W.S. Sheldrick and B. Schaaf Z. Anorg. Allg. Chem. 1994 620 1041. 70 K. Ebata T. Inada C. Kabuto and H. Sakurai J. Am. Chem. Soc. 1994 116 3595. 11 A. Kunai T.Sakurai E. Toyoda M. Ishikawa and Y. Yamamoto Organometallics 1994 13 3233. 72 R. Laurent A. Laporterie J. Dubac and J. Berlan Organometallics 1994 13 2493. i3 I. Abrahams S. J. Clark,J. D. Donaldson Z. I. Khan and J. T. Southern J.Chem.Soc.,Dalton Trans. 1994 2581. 74 D. Tudela J. Organomet. Chem. 1994,471 63; E. Garcia Martinez A. Sanchez Gonzalez A. Castineiras J. S. Casas and J. Sordo ibzd. 1994 469 41. Carbon Silicon Germanium Tin and Lead molecules at opposite ends of the ring.75 The structure of MeSnC1 shows the tin to be six-coordinate with two of the three chlorine atoms involved in bridging. The non-bridging Sn-Cl bond (228.3 pm) is 3.5 pm shorter than the two bridging Sn-C1 bonds with weak bridge bonds of 371.4~m.~~ Reacting Me -flSnClfl+ (n = 0-2) with water in the presence of 1,3-xylyl-18-crown-5 results in coordination of the water rather than hydrolysis.Crown.MeSnC1,.2H20 has six-coordination at tin with the three chlorine atoms mutually cis and the crown ether held through hydrogen bonding to the two water molecules. C2-n-butyl- 1,3-xylyl- 18-crown-5].Me2SnC12.H20 shows tin to be five-coordinate with water axial and hydrogen bonded to the crown ether.77 75 G.R. Willey A. Jarvis J. Palin and W. Errington J. Chem. SOC.,Dalton Trans. 1994 255. l6 W. Frank G.J. Reiss and D. Kuhn Acta Crystallogr. Sect. C 1994 50 1904. ” S. E. Johnson and C. B. Knobler Organornetallics 1994 13 4928.

ISSN:0260-1818    

DOI:10.1039/IC9949100053

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

6 Nitrogen Phosphorus Arsenic Antimony and Bismuth By K. K. Hllaand T. P. KEEb aDyson Perrins Laboratory University of Oxford South Parks Road Oxford OX1 3QY UK bSchool of Chemistry University of Leeds Leeds LS2 9JT UK 1 Introduction This Report is intended to cover some of the important developments in the chemistry of Group 15 elements over the year 1994. Indeed the Group 15 elements have such a large impact in a variety of scientific fields spanning organic inorganic materials and biological chemistries that any attempt at comprehensive coverage would be inappropriate in a report such as this. Consequently we have focused attention on a selection of the most recently published work in the areas of metallo-organic and coordination chemistry involving Group 15 elements.Such is the magnitude of annual published work in these areas (over 2000 articles were published on organophosphorus chemistry alone during 1994 according to the Chemical Abstracts Select Service) that our selection of material to include is of course highly subjective. The material for this Report has been compiled by on-line searching of the Bath Information and Data Service and the Chemical Abstracts Select Service and is complete to the end of 1994. 2 Nitrogen Nitrogen Compounds without Heterodonor Atoms.-Cationic complexes of the type [Pt(8-NH2-QUIN)L2][C10,1 and [Pt(8-NH2-QUIN)(L-L)][C104]2 (8-NH2-QUTN = 8-aminoquinoline) where L and L-L are mono- and bi-dentate nitrogen donor ligands respectively have been prepared. In aqueous solution they undergo reversible deprotonation of the amino group of the quinoline ligand (Scheme 1).l The corresponding ionization constants K have been determined by UV-VIS spec- trophotometry at 25 "C.A number of zerovalent palladium and platinum complexes of the form [M(N- N)(alkene)] containing bis(ary1imino)acenaphthalene (N-N = Ar-BIAN) and bis(pheny1imino)camphane (N-N = Ph-BIC) have been prepared and characterized.2 Stable complexes were obtained with electron-poor alkenes such as dimethyl fumarate fumaronitrile maleic anhydride and tetracyanoethene. Complexes bearing the asymmetric ligands Ar-BIAN (1)and Ph-BIC (2)were obtained as mixtures of isomers. G. Annibale L. Cattalini and F. Guidi J. Chern. SOC.,Dalton Trans. 1994 731. R. van Asselt C.J. Elsevier W. J. J. Smeets and A. L. Spek lnorg. Chem. 1994 33 1521. 67 K.K. Hii and T.P. Kee 2+ H I L or L-L = 4-CI-Py pyridine (Py) 4-Me-Py 4-H2N-Pyl NH3,ethylenediamine tetramethylenediamine Scheme 1 A Ph Ar (1) Ar-BIAN (2) Ph-BIC Ph-N?-fN-ph Ph"yN'Ph X (3)X = 0,S NCCeHs NC02Et From IR UV 'H and 13C NMR spectroscopies and substitution reactions it was concluded that back donation of electron density from the metal to the alkene is the major factor determining the stability of the complexes. Some of the complexes show fluxional behaviour explained by invoking rotation of the alkene around the metal-alkene bond. It appears as though alkene substitution occurs via a fast associative mechanism in the case of Ph-BIAN complexes but via a slow dissociative mechanism for complexes of 2,6-PriC,H3-BIAN.The same group have reported on a number of related chemical studies with Ar-BIAN type ligands during the year.3 Yellow crystals of formula [La(O,CCH,)(NCS),(C,,H 8N6)] have been syn- thesized by the condensation of 1,2-diaminobenzene and 2,6-pyridinedicarboxal- dehyde in the presence of lanthanum(n1) acetate followed by partial acetate-thiocyanate metathe~is.~ The complex has been characterized by single-crystal X-ray diffraction study which reveals the lanthanum ion to be ten-coordinate linked to six nitrogen atoms of the macrocyclic ligand to the nitrogen atoms of two isocyanates on ' R. van Asselt and C. J. Elsevier Tetrahedron 1994,50,323;R. van Asselt and C.J.Elsevier Organometallics 1994,13,1972; R. van Asselt E. E. C.G. Gielens R. E. Rulke K. Vrieze and C.J. Elsevier J. Am. Chem. Soc. 1994 116 977; R. van Asselt E. Rijnberg and C. J. Elsevier Orgunometallics 1994 13 706. F. Benetollo G. Bombieri and L. M. Vallarino Polyhedron 1994 13 573. Nitrogen Phosphorus Arsenic Antimony and Bismuth the opposite sides of the macrocycle and to a bidentate chelating acetate. IR and NMR ('H and I3C) spectroscopy on the complex were also recorded and fully assigned. The crystalline trilithium salt Li,N,N {N,N3-= [(Me,SiNCH,CH,),N]3-) has been shown to react with VCI,(DME) to give [V(N,N)Cl] in 45% yield.5 The structure of [V(N,N)Cl] determined by single-crystal X-ray diffraction is a distorted trigonal bipyramid with three silylamido in equatorial positions and axial chloride and amine donor groups.Reaction of [V(N,N)Cl] with Na/Hg in pentane solvent affords the trigonal monopyramidal complex [V(N,N)] in >90% yield. [V(N,N)] deoxygenates propylene oxide propylene-N-oxide nitrous oxide or DMSO to produce [V(O)(N,N)]. Treatment of [V(N,N)] with S or ethylene sulfide gives [V(S)(N,N)] while with elemental selenium the product obtained is [V(Se)(N,N)]. Subsequently PMe abstracts selenium from [V(Se)(N,N)] forming MeP=Se and regenerating [V(N,N)]. The chalcogenide complexes [V(X)(N,N)] (X = 0,S Se Te) have all been characterized by "V NMR. The species [V(N,N)] reacts with trimethylsilylazide to give [V(NSiMe,)(N,N)] which may also be accessed by reduction of [V(N,)(N,N)] with Na/Hg followed by quenching with Me,SiCl.[V(N,N)] reacts with Ph"C,F to give [V(NC,F,)(N,N)] and with trimethylsilyldiazomethane to afford [V(NNCHSiMe,)(N,N)]. The compound [V(N-4-MeC6H,)(N,N)] has been pre- pared by the reaction of Li,N,N with [V(N-4-MeC6H,)C1,]. The species [V(NH)(N,N)] may be deprotonated and subsequently silylated to afford [V(NSiMe,)(N,N)].' New chiral ruthenium bis(oxazoliny1)pyridine complexes have been reported to be efficient catalysts for the asymmetric cyclopropanation of alkenes with diazoacetates. Heterocycles with an exocyclic 1,4-diaza-2,3-diene structure (3) have a-bonding and x-backbonding properties similar to diazadiene~.~ Investigations of the molybdenum complexes (4) and (5) reveal a dominant o-component and a relatively weak x-backbonding comparable to a related complex of pyridinecarboxaldehyde isop- ropylimine.The oxalamidine compound (ti),which is the precursor to (3) is present in the s-trans (E/E) geometry with two stable intramolecular bridges. Compound (6) reacts with iron@) and cobalt(1r) chlorides to afford polymeric coordination com- pounds. A series of new ruthenium complexes [Ru(@-C,H,)L~]~+ [Ru(q6-C,H,)L2C1] + [RU(y6-C6H6)L3C1]+,[RU(~6-C6H,)L4C1]+,[RU(l'/6-C6H6)L5C1]+ have been Syn- thesized by bridge-cleavage reactions between [Ru(rf-C,H,)Cl,] and compounds C.C. Cummins R.R. Schrock and W. M. Davis Inorg. Chem. 1994,33 1448. 'H. Nishiyama Y. Hoh H. Matsumoto S.B. Park and K. Hoh J. Am. Chem. Soc. 1994 116 2223. ' M.Doring H. Gorls and R. Beckert Z. Anorg. Allg. Chem. 1994 620 551. K.K. Hii and T.P. Kee L' R' L4;R' = H L5;R' = Me N-NH (7) X = S; (8)X = 0 L'-Ls. The structures of the complexes have been examined in solution by 'H NMR spectroscopy. The reaction of dimethyltin(1v) dichloride with N-phenylpyridine-2-car-baldimine results in the formation of a monomeric 1 1 complex Me,Cl,Sn(C,HsN=CHCsH4N-2).9 The ligand coordinates to the tin atom through its pyridyl and imine nitrogen atoms conferring a distorted octahedral geometry to the tin atom. The two methyl groups are trans with respect to each other whilst the two chlorine atoms occupy cis positions. The bond length between the tin and the imine nitrogen atom is 2.540(5)8,whereas the pyridyl nitrogen-tin distance is 2.439(4) A.Dimeric Li[N(SiMe,),] reacts with the nitdes 4-XC6H,CN (X = H Me) in a mixed solvent system of diethyl ether :hexane (1 10)to afford dimeric complexes of the form [4-XC,H4C(NSiMe,) .Li(NCC,H,X-4)] ,.lo Amides which result from the reaction of aminosilane (Me,SiNH),SiH with Bu"Li in the molar ratio's 1 1 and 1 :2 in non-polar solvents form a system in which the aminosilane the mono-amide (Me SiNLi)(Me SiNH) SiH di-amide (Me SiNLi) (Me,SiNH)SiH and tri-amide (Me,SiNLi),SiH are in equilibrium.' Z. Shirin R. Mukhherjee J. F. Richardson and R. M. Buchanan J. Chem. SOC.,Dalton Trans. 1994,465. S.G. Teoh S.B. Teo L. K. Lee and H. K. Fun J. Coord. Chem. 1994,33 69. lo M.S. Eisen and M. Kapon J. Chem. SOC.,Dalton Trans.1994,3507. Nitrogen Phosphorus Arsenic Antimony and Bismuth The templated condensation of 3,5-diacetyl-l,2,4-triazole with thiocarbohydrazide or carbohydrazide in the presence of one equivalent of Pb(SCN) produces the mononuclear [2 + 1) complexes (7) and (8).12 The coordination of cyanide by di-iron(nr) diporphyrins in chloroform has been studied by ‘H and 2H NMR spectroscopy in order to shed light on the reaction pathway and potential intermediate^.'^ Nickel(r1) complexes containing a range of hexa-aza macrocyclic ligands which also incorporate functional groups such as hydroxy and cyano functions into the pendant arms attached at uncoordinated bridgehead nitrogen atoms have been synthesized by the simple template condensation of ethylenediamine formaldehyde and primary amines with the appropriate functional group.l4 Ionic palladium(11) complexes of the types [PdCl(N-N’-N”)]Cl and [PdR(N-N- N”)]OTf [R = Me aryl; N-N’-N” = tridentate nitrogen donor ligands (9) (lo),and (ll)] have been prepared.I5 The chloro derivatives were obtained as yellow ionic complexes in excellent yields (81-93%). Single-crystal X-ray diffraction analyses reveal the expected distorted square planar geometry with three coordination sites taken up by nitrogen atoms and the fourth occupied by chloride. There is no interaction between the palladium centre and the second chloride ion. In the complex containing the PIC0 ligand the Pd-NMe distance is relatively short and is accompanied by a small trans N-Pd-N bond angle.Methyl derivatives were also obtained in good yields via the reactions of [PdIMe(TMEDA)] with AgOTf and the ligand of interest. An alternative route starting from [PdMe,(TMEDA)] was also reported. The molecular structure of [PdMe(NNN)OTq revealed a terdentate coordination mode for the NNN ligand. Yellow crystals of [PdMe(ONN’)(TMEDA)]OTf {ON” = 2-(hydroxymethyl)-6-[(dimethylamino)methyl]pyridine} were accidentally obtained from the reaction of [PdMe(MeCN)(TMEDA)]OTf with an impure sample of the NNN ligand con- taminated with ON”. The molecular structure shows the ONN’ ligand to be monodentate coordinated to the metal centre via its pyridyl nitrogen donor whilst the NMe and OH functions remain uncoordinated. The triflate anion is hydrogen bonded to the hydroxymethyl group.The first examples of simple arylpalladium(r1) cations containing tridentate ligands and a range of sterically and electronically disparate aryl groups were obtained in moderate to high yields (35-95%). NMR-based conforma Me2N NMe2 Me2N NMe2 (9) NNN (10) PMDETA (11) PIC0 P. Kosse E. Popowski M. Veith and V. Huch Chem. Ber. 1994 127 2103. I’ P. Souza A.I. Matesanz A. Arquero and V. Fernandez Z. Naturforsch. Tei B 1994 49 665. l3 S. Wolowiec and L. Latosgrazynski lnorg. Chem. 1994 33 3576. l4 M. P. Suh B.Y. Shim and T.S. Yoon Inorg. Chem. 1994 33 5509. l5 B.A. Markies P. Wijkens J. Boersma H. Kooijman N. Veldman A.L. Spek and G. van Koten Organometallics 1994 13 3244. K.K. Hii and T.P. Kee tional analyses of the NCCN moieties of the PICO- and PMDETA-containing complexes showed that the five-membered chelate rings were present in one of the two possible conformations.The rotational energy barriers of the aryl groups have been studied as a function of the ligand and were shown to increase in the order NNN < PICO < PMDETA. This is explained in terms of the positioning and orientation of the pyridyl and NMe,groups around the metal centre. The aryl rotation is found to be blocked in ortho-substituted aryl complexes leading to atropisomerism in the PMDETA c0mp1ex.l~ Nitrogen Compounds with Heterodonor Atoms.-A systematic review of the use of nitrogen based donor ligands in organometallic chemistry and homogeneous catalysis has been published.I6 The synthesis of cyclopentadienyl complexes containing the polydentate C,H,CH,NMe ligand and the Group 13 element gallium has been de~cribed.'~ The compounds (q'-C,H,CH,CH,NMe,)GaR (R = Br Me H) are obtained in good yields by salt elimination reactions.These compounds reveal intramolecular coordina- tion of the nitrogen atom in the side-chain and consequently monomeric structures which are sufficiently volatile to show potential for metallo-organic chemical vapour deposition (MOCVD) processes. Three diastereomeric Pd" complex cations containing the orthometallated (S)-dimethyl[ 1-(a-naphthy1)ethyllaminetogether with the (R,R)-,(S,S)-,and (R,S)-forms of N,N,N',N'-tetramethyl-2,3-butanediamine have been prepared as the perchlorate salts.' The coordination geometry around the palladium atom is distorted significant- ly from square planarity in each case due to severe ligand-ligand interactions.In solution the diamine ligands of these complexes are found to be labile evidenced by facile intermolecular ligand redistribution between diastereoisomers. A series of cyclometallated Pd" complexes derived from 2-substituted-8-quinolinol have been prepared." An ethyl acetoacetate substituent in the 2-position was shown to exist predominantly in the keto form. When these ligands were treated with K,[PdCl,] in the presence of pyridine the corresponding pyridine adducts were isolated and shown to be racemic in the crystalline state by single-crystal X-ray diffraction analysis. When the pyridine ligand is exchanged with L-( -)-1-phenylethylamine a mixture of (S,S)and (R,S)diastereoisomers results from which each isomer may be separated by column chromatography.Reduction of 2,3 :9,10-dibenzo-5,12-diaza-l,8-dioxacyclotetradecane-5,1l-diene with NaBH in ethanol solvent generates 2,3 :9,10-dibenzo-5,12-diaza-l,8-dioxacyc-lotetradecane in high yield. The secondary amino groups in this cycle may be alkylated readily to afford the corresponding dialkylated macrocycle. A number of new coordination complexes of these ligands with Ni" Cu" and Co" have been reported.,' The systematic variation of the donor atom set in a dibenzo-substituted 17-membered ring structure (12) has been investigated with relation to the effects upon the ability of the ligand framework to discriminate between Ag' and Pb" ions.The compound containing a [S,N,S,] set of donor atoms afforded a discrimination of the '' A. Togni and L. M. Venanzi Angew. Chem. Int. Ed. Engl. 1994 33 497. " P. Jutzi and M. Bangel J. Organomet. Chem. 1994 480 C18. S.Y. M. Chooi M. K. Tan P. H. Leung and K. F. Mok Inorg. Chem. 1994 33 3096. A. Yoneda T. Hakushi G.R. Newkome and F. R. Fronczek Organometallics 1994 13 4912. lo Y. Gok and S.Z. Yildiz Z. Anorg. Allg. Chem. 1994 620 959. Nitrogen Phosphorus Arsenic Antimony and Bismuth order of lo9 in favour of Along similar lines the same authors report on the interaction of Zn" and Cd" with the same series of mixed donor atom macrocycles including the determination of a number of 1 1 stability constants.22 0 NH 00 0s S NH so ss Metal-ion templated cyclocondensations of two acylic diamines containing nitrogen and sulfur heteroatoms with pyridine-2,6-dicarboxaldehydein the presence of Pb" Hg" Cd" and Ag" afforded 1 :1 complexes of the appropriate metal ion with the corresponding 18-membered potentially hexadentate [N,S23 diimine macrocycle (1 3) or (14).23 The soluble palladium mercury and cadmium complexes show strong metal-imine interactions in solution by NMR.Single-crystal X-ray data have been collected for [Hg(13)(MeOH)(H20)][C10,] and [Hg(l3)(SCN),].MeOH. In both complexes the macrocycle adopts a stepped conformation with respect to the two pyridyl units; a conformation which facilitates endo-dentate configurations for the sulfur donors which interact through long bonds to the metal which is located towards the trimethine part of the macrocycle.This results in the second pyridine nitrogen atom being remote and uncoordinated. Attempts to induce coordination of the amine group in aminophosphonate complexes of Cr"' were reported to be unsuccessful. However N-phosphonomethyl- glycine oxygen atoms are coordinated to the metal centre.24 A similarly coordinated complex of N,N-diphosphonomethylglycine is unstable and reverts to an isomer in which the amino group is uncoordinated. Several reasons for the failure of the amino group to bind to a metal in such systems were explored. Steric factors appear to be relatively unimportant whereas the following are presumed to be contributing factors (i) there is a thermodynamic driving force for the transfer of a proton from the phosphonyl oxygen atom to nitrogen (acid-base reactivity); (ii) coordination of the phosphonate end of an aminophosphonate appears to lower the basicity of the amine group much more than carboxylate coordination in an aminocarboxylate; (iii) in an " K.R. Adam D.S. Baldwin A. Bashall L. F. Lindroy M. McPartlin and H. R. Powell f. Chem. Soc. Dalton Trans. 1994 237. '' K. R. Adam S.P.H. Arshad D.S. Baldwin P.A. Duckworth A. J. Leong L.F. Lindroy B. J. McCool M. McPartlin B.A. Taylor and P.A. Tasker Inorg. Chem. 1994 33 1194. 23 A. Bashall M. McPartlin B. P. Murphy H. R. Powell and S. Waikar J. Chem. Soc. Dalton Trans. 1994 1383. 24 C.R. A. Rajendram and P. E. Hoggard J. Coord.Chem. 1994 33 15. 74 K.K. Hii and T.P. Kee aminophosphonate the nitrogen lone pair orbitals lie lower in energy than they do in aminocarboxylates so decreasing the energy of the donor-acceptor interaction with metal orbitals. The tetradentate ligand N,N'-bis[2-(diphenylphosphino)phenyl]propane- 173-dia- mine (P2N2) has been synthesized characterized and its electrochemical properties and coordination abilities towards transition metal ions at the water/l,2-di-chloroethane interface examined by cyclic ~oltammetry.~~ It was found that the P,N ligand can coordinate to the Cu" ion the transfer of Cu" ions is facilitated in the presence of counter-ions such as chloride bromide and acetate. An interfacial reaction between the ligand and metal ion has been proposed.The unique selectivity of the P,N,ligand for Cu" makes it a very useful hydrophobic ligand as an extractant in separation processes. 3 Phosphorus A number of general reviews on organophosphorus chemistry have appeared including the chemistry of low-coordinated hypervalent phosphorus,26 chemical bonding in phosphines phosphine oxides and phosphinium ylide~,~~ and a classification of covalent partial structures of phosphorus in polycyclic phosphanes extendable also to other covalently dominated structures including the allotropes of phosphorus.28 Phosphazanes and Phosphazenes.-The chemistry of linear cyclic and polymeric phosphazenes have been covered in a recent review.29 Crystal structures of (4- ha1ogenophenoxy)phosphazenes of the type OP(OR),NP(OR) and [NP(OR),], where OR = OC6H4F-4 OC,H,Cl-4 OC6H4Br-4 and OC,H,I-4 were determined.Subsequent comparison of the structures of these cyclic and linear short-chain species showed that the P-N bond lengths in these compounds are very similar. Evidence for side-group stacking can be detected. Group 6 metal carbonyl complexes of bis(pyrazoly1)cyclotriphosphazenes have been studied.30 Complexes of the type [M(CO),L] have been characterized by NMR and IR data. New monospirocyclotriphosphazenes and trispirocyclotriphosphazenes have been prepared from the reactions of (NPCl,) with aromatic ortho dinu~leophiles.~~ Reactions of palladium chloride with amino spirocyclic cyclotriphosphorazenes have been reported to afford novel monometallic and bimetallic complexes by hydrolysis of a A5-diazaphospholane ring.The structures of (15) and (16) have been determined by X-ray ~rystallography.~' The first detailed investigations of the reactions of polyfluoro-mono and dialkoxy- silanes with cyclic fluorophosphazenes have been reported and compared with reactions of the nonfluorinated analogs. The methods offers an easy and elegant route to the poorly studied bridged and pendant phosphazene compounds. For the first time '' Y. F. Chen D.J. Schiffrin P. Guerriero and P.A. Vigato Inorg. Chem. 1994,33 765. 26 A.J. Arduengo and C.A. Stewart Chem. Rev. 1994 94 1215. '' D.G. Gilheany Chem. Rev. 1994 94 1339. '* M. Haser J. Am. Chem. SOC. 1994 116 6925. l9 C.W. Allen Coord. Chem. Rev. 1994 130 137.30 A. Chandrasekaran S.S. Krishnamurthy and M. Nethaji J. Chem. SOC. Dalton Trans. 1994 63. 31 H. R. Allcock U. Diefenbach and S. R. Pucher Inorg. Chem. 1994,33 3091. 32 A. Chandrasekaran S. S. Krishnamurthy and M. Nethaji Znorg. Chem. 1994 33 3085. Nitrogen Phosphorus Arsenic Antimony and Bismuth (17) a transformation of bridged phosphazene compounds to spiro compounds has been observed and monitored by I9F NMR spectro~copy.~~ The spirocyclic cobaltphosphazene (17) undergoes ring enlargement reactions by treatment with oxygen sulfur or selenium. The resulting paramagnetic spirocyclic cobalt-phosphazenoids possess eight-membered chelate rings connected at the spiro- cobalt(1r) centre to form a tetrahedral CoE core.34 Acyclic silylated phosphazenes of the type HN(PR,NSiMe,) react quantitatively with molecules MMe (M = Al Ga In) to give the ring compounds N(PPh,NSiMe,),MMe, which have been investigated by single-crystal X-ray diffraction.NMR spectroscopy indicates increasing Lewis acidity of the metal containing fragments in the order TnMe < GaMe IA1Me,.35 The stereoselective formation of skeletally stabilized di- and tri-phosphazanes from reactions of phosphadiazoles with PhPCl, Ph,PCl and PhP(Et,N)Cl has been examined36 along with reactions of the hexachlorocyclodiphosphazane [MeNPCl,] with primary aromatic amines and methanolic potassium hydroxide which lead to the formation of highly basic bispho~phinimines.~~ Urethane and urea derivatives of (NPCI,) have been prepared and the crystal structure of a spirocyclic phosphazene with a phosphacyanuric loop (17) reported.,' The regioselectivity molecular cleft selectivity and conformational properties of the skeletally stabilized triphosphazanes (18)-(21) and a series of new derivatives has been reported.39 33 A.J. Elias R. L. Kirchmeier and J. M. Shreeve Inorg. Chem. 1994 33 2727. 34 J. Ellermann J. Sutter F. A. Knoch and M. Moll Chem. Ber. 1994 127 1015. 35 R.Hasselbring H. W. Roesky A. Heine D. Stalke and G. M. Sheldrick Z. Naturforsch. Teil B 1994,49 43. 36 S.A. Katz V. S. Allured and A.D. Norman Inorg. Chem. 1994 33 1762. 37 R.Murugavel S. S. Kumaravel S. S. Krishamurthy M. Nethaji and J. Chandrasekhar J. Chem. SOC. Dalton Trans. 1994 847. 38 A. A. van der Huizen P.L. Buwalda T. Wilting H. Pol A. P. Jekel A. Meetsma and J. C. van der Grampel J. Chem. SOC. Dalton Trans. 1994 577. 39 S.M. Young A. Torassoli J. M. Barendt C. A. Squiers,F.Barthelemy,R.Schaeffer R.-C. Haltiwanger and A.D. Norman Inorg. Chem. 1994 33 2748. K.K. Hii and T.P. Kee Phosphines.-The preparation of scalemic P-chiral phosphines and their derivatives has been re~iewed.~' The balance of steric and electronic factors in metal-phosphine coordination with respect to the phosphine twist has also been ~overed.~' The synthesis and structural characterization of mesityldiphenylphosphine dimesityl- phenylphosphine and trimesitylphosphines have been reported.42 A convenient route to diphenyl(1-substituted-2-naphthy1)phosphines of the type (22)in which a novel nucleophilic aromatic substitution reaction is employed has been described.43 The functionalized diphosphines LiH(PBu'), Li(PBu'), K,(PPr'), and (Pr'P),Cl have been estimated as versatile synthetic building blocks for the synthesis of open-chain and cyclic t-butyl or isopropylph~sphines.~~ Novel sulfur- and phosphorus-containing oxazolines have received a lot of attention as a result of their applications as co-catalysts in asymmetric synthesis; in particular palladium-catalysed asymmetric allylic sub~titution.~' R2P$.HI (22) X=C,O,N (23) R' = Ph ptolyl DBP R2= Ph xylyl Me R3= Ph mxylyl (24) R = Pf Bu",Pi Ph Chiral tripod ligands (23) containing three different donor groups at their neopentyl backbone have been described46 along with a range of applications and chemistry of complexes containing these ligand~.~~ Aspects of the coordination chemistry of potentially tridentate diphosphinoamido ligands N(CH,CH,P,) have been studied.48 40 K.M. Pietrusiewicz and M. Zablocka Chem. Rev. 1994 94 1375. 41 D. L. Lichtenberger and M. E. Jatcko J. Coord. Chem. 1994 32 79. 42 J. F. Blount D. Camp R.D.Hart P.C. Healy B. W. Skelton and A.H. White Aust. J. Chem. 1994,47 1631. 43 T. Hattori J. Sakamoto N. Hayashizaka and S. Miyano Synthesis 1994 199. 44 M. Baudler H. Tschabunin H. Suchomel and J. Hasenbach Z. Naturforsch. Teil B 1994 49 773. 4s J. V. Allen G.J. Dawson C. G. Frost J. M. J. Williams and S. J. Coote Tetrahedron 1994 50 799. 46 T. Seitz A. Muth and G.Huttner Chem. Ber. 1994 127 1837. 47 A. Muth 0.Walter G. Huttner A. Asam L. Zsolna and C. Emmerich J. Organomet. Chem. 1994,468 149. 48 Y. B. Yang M. Pabel A.C. Willis and S. B. Wild J. Chem. Soc. Chem. Commun. 1994 475. Nitrogen Phosphorus Arsenic Antimony and Bismuth 77 trans-Chelating chiral diphosphine ligands bearing flexible P-alkyl substituents (alkyl-traps) as in (24) have been found to have applications in the rhodium-catalysed asymmetric hydrosilylation of simple ketones,49 and also in the asymmetric Michael reaction of 2-cyanopropionates with electr~philes.’~ In the latter system enantiomeric excesses as high as 93% were obtained. Reaction of chitosan with hydroxymethyl phosphines R,PCH,OH proceeds readily via a Mannich-type condensation reaction with the polymer NH groups to give a new type of chiral immobilized phosphine.’ Water-soluble primary and secondary phosphines of the form R,N(CH,),PPh (R = Me Bun C5H10 C,H,O 2-(l-methyl-2-pyrrolidinyl); rn = 2 3 6 10 11) containing ammonium groups in the side-chain have been synthesized.Selective N-quaternization of the amine side-chain with alkyl iodides affords novel water- soluble ph~sphines.’~ Water soluble secondary and tertiary phosphines were also obtained with sulfonated aromatic resid~es.~ On a similar theme direct sulfonation of dppe leads to water-soluble 1,2-bis[bis(3-sodiosulfonatophenyl)phosphino]ethane which is found to be more electron-accepting than the non-sulfonated analog. Several coordination complexes of rhodium nickel palladium and platinum have been reported and water-soluble rhodium compounds prepared in situ show only poor selectivity in the hydroformylation of 1-octene under biphasic condition^.'^ Free radical addition of diphenylphosphine ethylenebis(phenylphosphine) and phenylphosphine to alkynols alkyne ethers unsaturated carboxylic acids and esters and p-lactones has been described which in a number of cases led to water-soluble phosphines.’’ The synthesis and characterization of the rac- and meso- compounds (25) and (26) have been rep~rted.’~ Racemic (R)-and (S)-(6,6’-difluorobiphenyl-2,2’-dilyl)bis(diphenylphosphine)has been synthesized in four steps and resolved.These ligands are of the electron-poor biphenyl-type and were found to be efficient catalysts for the hydroboration of alkenes by catecholborane.’’ Hybrid ligands based on phosphorus and nitrogen donor atoms such as (27) have been obtained by the base-catalysed addition of diphenylphosphine or 2-vinylpyridine to the primary or secondary phosphines 2-py(CH2),PR’H (R’ = H Ph) HMeP(CH,),PMeH or by the alkylation of the organolithium phosphides R,P(CH,),PMeLi or 2-py(CH2),PR’Li (R = Ph Pr’; R‘ = H Ph) with 2-(2-chloro- ethy1)pyridine or di-t-butylphosphetanium bromide.Square planar complexes of nickel palladium and platinum were also synthesized. 58 The synthesis characterization and catalytic properties of Group 6 metal complexes of the compounds (28) have been reported.59 The synthesis and fluxional behaviour of hemi-labile ether phosphines containing OY M.Sawamura R. Kuwano and Y. Ito Angew. Chem. Int. Ed. Engl. 1994 33 111. 50 M. Sawamura H. Hamashima and Y. Ito Tetrahedron 1994 50 4439. 51 W. Henderson G. M. Olsen and L.S. Bonnington J. Chem. Soc. Chem. Commun. 1994 1863. 52 D. J. Brauer J. Fischer S. Kucken K. P. Langhans 0.Stelzer and N. Weferling Z. Naturforsch. Teil B 1994,49 1511. 53 0.Herd A. Hessler K. P. Langhans 0.Stelzer W. S. Sheldrick and W. Weferling J. Organomet. Chem. 1994 475 99. s4 T. Bartik B. B. Bunn B. Bartik and B.E. Hanson Inorg. Chem. 1994 33 164. 55 K. Heeschewagner and T. N. Mitchell J. Organornet. Chem. 1994 468 99. 5h G.A. Bowmaker and J. P. Williams Aust. J. Chem. 1994 47 451. 57 H. Jendralla C.H. Li and E. Paulus Tetrahedron Asymmetry 1994 5 1297.58 A. Hessler J. Fischer S. Kucken and 0.Stelzer Chem. Ber. 1994 127 481. 5y T. J. Kim Y. H. Kim E. J. Kim S. H. Oh H. S. Ki and J. H. Jeong Bull. Korean Chem. Soc. 1994,15,379. K.K. Hii and T.P. Kee PhMePFpMePh Fe Ph2P I Me @-PPhp (28) (29) phosphorus and oxygen donor atoms has been studied by 31P NMR and line-shape analysis.60ct-Phosphine enolates [Ph,P(CH,)O .* * Li(THF),] were isolated and fully characterized and the reaction of this enolate with Cp,ZrCl was found to lead to zirconium enolates which react with benzaldehydes to give compounds of the type (29). ’ Two new C chiral bidentate phosphorus ligands have been prepared in enan- tiomerically pure form. The two phosphorus centres bear electron-withdrawing groups and are linked by a truns-cyclopentane-l72-diol-derived bridge.62 Reactions of the sterically hindered diphosphines (Ph,P)C=CHR (R = Me or Ph) with E (E = S or Se) afforded the corresponding mono- and di-chalcogenides and the mixed sulfur and selenium derivatives.‘H 31P,and I3C NMR parameters were rationalized by the relative P-E and phosphorus lone-pair orientation^.^^ It has been reported that triaryl and trialkyl phosphine dichlorides can be synthesized conveniently and in high yields by the oxidation of tertiary phosphines with tri~hosgene.~~ A single diastereomer of ( -)-methylmesitylphosphine has been isolated by frac- tional crystallization in 94% purity effecting the first resolution of a free secondary phosphine chiral at pho~phorus.~’ Chiral functionalized bisdiphenylphosphines have been prepared and isolated using natural tartaric acid via the dihydrophosphorylation of dimethyl 4,5-0-iso-propylidene-2,6-octanedienedioate7 4,5-O-isopropy1idene-2,6-octanedienedinitri1e7 and bis S(H)-2-f~ranone.~~ Optically active 2-functionalized-2’-diphenylphosphino-1,1’-binaphthyls (MOP’S) were prepared.Several functional groups were introduced on the MOP skeleton by 60 E. Lindler M. M. Haustein H. A. Mayer H. Kuhbauch K. Vrieze and B. Deklerkengels Znorg. Chim. Acta 1994 215 165. 61 P. Veya C. Floriani A. Chiesivilla and C. Guastini Organometallics 1994 13 208. 62 E. P. Kundig C. Dupre B. Bourdin A. Cunningham and D. Pons Helv. Chim. Acta 1994 77 421. 63 J. L. Bookham F. Conti,H. Christina E.McFarlane W. McFarlane and M. Thornton-Pett J. Chem. Soc. Dalton Trans. 1994 1791. 64 A. Wells Synth. Commun. 1994 24 1715. 65 A. Bader M. Pabel and S.B. Wild J. Chem. Soc. Chem. Commun. 1994 1405. 66 Y. Gourdel P. Pellon L. Toupet and M. Lecorre Tetrahedron Lett. 1994 35 1197. Nitrogen Phosphorus Arsenic Antimony and Bismuth transition metal catalysed transformation of aryl triflate~.~~ In a similar genre the monodentate phosphine ligand (30)was prepared and used in the palladium-catalysed asymmetric reduction of allylic esters with formic acid giving optically active olefins in up to 85% enantiomeric excess (e.e.).68 New optically active ruthenocenylbis(phosphines) (31)and ethylamine analogues have been prepared by way of stereospecific lithiation.A single-crystal X-ray diffraction study of the palladium dichloride complex revealed the [P-Pd-PI bite angle to be larger than that of the ferrocenyl analogue. The ruthenocenylphosphine affords high enantioselectivities in the palladium-catalysed asymmetric silylation of allylic chlorides and in the palladium-catalysed cyclization of 2-butenylene dicarbonate with methyl acetylacetate forming a vinyldihydrofuran in up to 86% e.e.69 Optically active expanded chelate phosphines have been synthesized via the reaction of bromotolyl bromoxylyl and bromodiphenylmethane derivatives with a R-bis(dichlorophosphino)alkanes.70 New chiral phosphines derived from carbohydrates such as D-mannitol and D-sorbitol have been de~cribed.~ The chiral phosphine complexes display moderate enantioselectivity in the asymmetric hydrogenation of the methyl ester of benzamido- cinnamic acid.(lR 1’s)-(dipheny1phosphino)ethylbenzene and (lS l’S) (lR l’R)-l,3-bis[l-(dipheny1phosphino)ethyllbenzene derivatives have been reported and their cyclo- metalation reactions with platinum(I1) compounds studied.72 67 Y. Uozumi N. Suzuki A. Ogiwara and T. Hayashi Tetrahedron 1994 50 4293. 68 T. Hayashi H. Iwamura Y. Uozumi Y. Matsumoto and F. Ozawa Synthesis 1994 526. 69 T. Hayashi A. Ohno S.J. Lu Y. Matsumoto E. Fukuyo and K. Yanagi J. Am. Chem. SOC. 1994,116. 422 I. 70 H. Brunner and J. Furst Tetrahedron 1994 50 4303. 71 B. M. Choudary M. R. Sarma A. D. Prasod and N. Narender Indian J. Chem. Sect. B 1994 33 152.72 F. Gorla L. M. Venanzi and A. Albanati Organometallics 1994 13 43. 80 K.K. Hii and T.P.Kee Phosphaalkenes Phosphaallenes and Phosphaa1kynes.-The use of phosophaalkynes as new building blocks in heterocyclic chemistry has been reviewed.73 The phosphaal- kene phenylbis(trimethylsily1) methylene phosphine has been shown to react readily with a,a-disubstituted alkenes containing allylic hydrogens to yield products reminis- cent of those expected from an ene-type reaction.74 Transient phosphaalkenes are formed under high-dilution conditions by the Lewis-base induced rearrangement of vinylphosphines. In the presence of dienes they react to afford cyclic phosphines in high yield^.'^ Phosphaalkynes such as But-C = P have been shown to undergo cyclodimerization at a molybdenum centre to afford a 1,3-diphosphacyclobutadiene complex,76 or a novel trimerization in the coordination sphere of ruthenium complexes to give a 1,3,5-triphosphabenzene,~-3-phosphaalkyne complex.77 In these complexes the four- membered ring is found to be q3-ligated to the metal centres.The metalo-phosphaalkenes (q'-C,Me,)(CO),FeP=C(R)(SiMe,) and Me0,C-C-C-CO,Me undergo a (I3+ 21 cycloaddition to afford the metallo- heterocycles (q5-C Me,)( CO)FeC(O)C(CO,Me)=C(CO,Me)P=C(R)SiMe with exocyclic P=C double bonds7' Silene generated in situ is trapped by Bu'-C-P to form a diphosphatricyclobenzo-heptane (32).79 The molecular structure of 2-(diisopropylamino)-l-;l-3-phospha-ethyne PriNCEP has been investigated by X-ray diffraction." The first examples of symmetrically bridging p-perpendicular phosphaalkyne complexes (33)have been reported and structural features established by solution and solid-state 31P{ 'H) NMR spectroscopy." The first carbon-phosphorus-aluminium cage compound has been prepared by the cyclooligomerization of phosphaalkynes with trialkylaluminium compounds.De- pending on the solvent two completely different products (34) or (35) can be obtained.82 The cyclopropylcarbonylbis(trimethylsily1)phosphanes were prepared from the corresponding cyclopropanecarboxylic acids. These products were observed to undergo trimethylsilyl group shifts at room temperature to yield the phospaalkenes (36) as a mixture of (E)-and (Z)-i~omers.~~ The synthesis and rearrangement of intramolecularly stabilized 1-0' ,3-a2-diphos-phaallylic cations (37) into intramolecularly stabilized 1-a' 3-a3-diphosphaallylic cations (38) has been observed.84 Unstabilized P-methyl- 1-phosphaallenes (38) have been prepared by a base-73 M.Regitz J. Heterocycl. Chem. 1994 31 663. 74 M. Suzuki K. Sho K. Otani T. Haruyama and T. Saegusa J. Chem. Soc. Chem. Commun. 1994 1191. 75 A.C. Gaumont J.C. Guillemin and J. M. Dennis J. Chem. Soc. Chem. Commun. 1994 945. 7h P.B. Hitchcock M. J. Maah and J. F. Nixon J. Organomet. Chem. 1994 466 153. 77 P.B. Hitchcock C. Jones and J. F. Nixon Angew. Chem. Int. Ed. Engl. 1994 33 463. M. Witt and H. W. Roesky Chem. Rev. 1994 94 1163. 7y B. Breit R. Boese and M. Regitz J. Organomet. Chem. 1994 464 41. G. Becker M.Bohringer R. Gleiter K. H. Pfeifer J. Grobe D. Levan and M. Hegemann Chem. Ber. 1994 127. 1041. S.I. Alresayes C. Jones M. J. Maah and J. F. Nixon J. Organomet. Chem. 1994 468 107. ''B. Breit,A. Hoffmann U. Bergstrasser,L. Richard F. Mathey and M. Regitz Angew. Chem. Int. Ed. Engl. 1994 33 149 1. x3 A. B. Kotstitsyn 0.M. Nefedov H. Heydt and M. Regitz Synthesis 1994 161. 84 M. Soleihavoup Y. Canac A.M. Polozov A. Baceiredo and G. Bertrand J. Am. Chem. Soc. 1994,116 6149. Nitrogen Phosphorus Arsenic Antimony and Bismuth Ph2P PPh2 I I dh /Rh Ph2b,3. PPh2 I But But Me3SiO' (34) Me\ ,C =C=P-Me Me (37)R = Pi induced dehalogenation of 1-chlorovinylmethylphosphinesor rearrangement of 1-alkynyl-methyl-ph~sphines.~ Phosphetane and Phosphirane.-Reactions of low-coordinated phosphorus com-pounds with dichlorocarbene and successive conversions of the resulting phosphiranes into phosphacumulenes phosphaallenes or phosophaalkynes were reviewed.86 The direct syntheses of 1-phenylphosphetane and 1-phenylphosphirane along with the crystal and molecular structures of cyclotrimerization precursor complexes fuc-[Mo(CO),(PhPCH2CH2CH2),] andfuc-[Mo(CO),(PhPCH2CH2)J have been rep~rted.~ Phosphorus and Phosphonium Y1ids.-Synthetic applications of metalated phos- phonium ylids have been reviewed.88 A study of the reactivity of 2-F-alkylethyl thiocyanates and isothiocyanates towards stabilized phosphonium ylids has led to a new method for the introduction of a perfluoroalkyl chain into the structure of a stabilized phosphonium ylid.The method has been extended with thiocyanates to allow the introduction of an alkyl or alkylaryl chain into such a structure.89 85 J. C. Guillemin T. Janati J. M. Denis P. Guenot and P. Savignac Tetrahedron Lett. 1994 35 245. 86 K. Toyota and M. Yoshifuji J. Synth. Org. Chem. Jpn 1994 52 580. " Y.B. Young M. Pabel A.C. Willis and S. B. Wild J. Chem. SOC. Chem. Commun. 1994 475. " H. J. Cristau Chem. Rev. 1994 94 1299. E. Bollens S. Szonyi H. Trabelsi and A. Cambon J. Fluorine Chem. 1994 67 177. '9 82 K.K. Hii and T.P. Kee The synthesis and reactivity of perfluoroalkylmethyleneoxy(tris-dimethy1amino)phosphonium salts with nucleophiles has been reported.’O The dehydrofluorination of alkoxydifluorophosphoranes proceeds under kinetic control to afford diastereoisomers of phosphorus ylids.In the presence of lithium fluoride the most thermodynamic diastereoisomer of these is formed.” Novel a-mercurio-substituted phosphorus ylides of the form Ph,P=CRHgN(SiMe,) (where R = Me Et Pr’ Ph) have been prepared and ~haracterized.~~ Their reaction with benzaldehyde yields vinylmercury amides. In some of these reactions the stereochemistry favoured was contrary to that of the established Wittig olefination reaction with non-stabilized ylids. The reaction of vicinal triketones with cumulative phosphorus ylids affords access to phosphoranylidenecyclobutanes .9 Phosphites.-The ring-opening of the phosphorinane ring ClP(OCH,CMe,CH,O) occurs upon treatment with diols and N-chlorodiisopropylamine (NCDA) or with quinones.The single-crystal X-ray structure of one of these products revealed a symmetrical anti-chair conformation of the eight-membered ring. In contrast the phenylene phosphorochloridite ClP(O,C,H,) affords pentacoordinated phos-phoranes in similar reaction^.'^ New chiral phosphinephosphites (R)-(5,5’-dichloro-2-diphenylphosphino-4,4,6,6’-tetramethylbiphenyl-2’-yl) and its enantiomer have been shown to be highly efficient ligands for the rhodium-catalysed asymmetric hydroformylations of a variety of olefinic substrate^.^^ Phosphorus Macrocycles and Cryptands.-The synthesis of phosphorus-containing macrocycles and cryptands has been reviewed.96 Photolysis of cis-{Mo(CO),[Ph,P(CH2CH20)4CH2CH2PPh2]} gave the trans- complex (39) which is the first example of a metalla-crown ether in which the bis(phosphorus donor) polyether ligand is trans coordinated.It is also a rare example of a octahedral complex with a trans-spanning bis(phosphine) ligand.97 The behaviour of 4-phenyldinaphthophosphole(40) the first phosphole with axial chirality towards palladium and platinum(I1) metal centres has been investigated. In some complexes the phosphole ligand is fluxional at room temperature and undergoes rapid atropisomerization of the binaphthyl framework even in the bound state.98 The multifunctional phosphane ligand (41)is derived from 4-t-butylcalix[4]arene. This large diphosphane possesses C symmetry and behaves as a cis-and trans- bridging ligand.99 90 M.Alloch and C. Selve J. Fluorine Chem. 1994 66 31. 91 0.I. Kolodiazhnyi S. Ustenko and 0.Golovatyi Tetrahedron Lett. 1994 35 1685. 92 M. Steiner H. Pritzkow and H. Grutzrnacher Chem. Ber. 1994 127 1177. 93 F. M. Soliman A. A. Elkateb I.T. Hennawy and H.A. Abdelmalek Heteroatom Chem. 1994 5 121. 94 M.A. Said K. C. K. Swarny C. C. Mohan and N. V. Lakshrni Tetrahedron 1994 50 6989. T. Hayashi N. Sakai K. Nozaki and H. Takaya Tetrahedron Lett. 1994,35,2023;N. Sakai K. Nozaki 95 and H. Takaya J. Chem. SOC.,Chem. Commun. 1994 395. 96 A.M. Caminade and J. P. Majoral Chem. Rev. 1994 94 1183. 97 G. Gray and C. H. Duffey Organometallics 1994 13 1542. 98 S. Gladiali D. Fabbri G. Banditelli M. Manassero and M. Sansoni J.Organomet. Chem. 1994,475,307; K. Tani H. Tashiro M. Yoshida and T. Yarnmagata J. Organornet. Chem. 1994 469 229. 99 C. Loeber D. Matt A. Decian and J. Fischer J. Organomet. Chem. 1994 475 297. Nitrogen Phosphorus Arsenic Antimony and Bismuth 4 Arsenic Metal-free Arsenic Compounds.-The first cycloaddition reactions of dimeric arsenium ions (42) have been reported."' A number of phenoxarsin-10-yl-diorganodithiophosphinatesO(C,H,),AsS,PR (R = Me Et Ph; 43) have been prepared by the treatment of 10-chlorophenoxarsine with salts of the corresponding dithio compounds in CH,Cl The compound were characterized by IR mass spectrometry and 'H 13C and 31PNMR spectroscopy. A single-crystal X-ray diffraction analysis was reported on the compound with R = Ph.This compound exhibits a dimeric quasi-tricyclic structure based upon intra- and inter-molecular As * -S secondary bonds which appears to be unique in arsenic-sulfur chemistry. The phenoxarsine unit is non-planar with a dihedral angle of 154.4' between the planes of the two aromatic rings. ao>o AS I The sterically crowded diarsanylsilane (2,4,6-Pr~C6H,)(Bu')Si(AsH,),has been synthesized by the reaction of (2,4,6-Pr',C,H,)(Bu')sic12with two equivalents of LiAsH,(DME) in 80% yield."' Treatment of (2,4,6-Pr'jC,H,)(But)Si(AsH,),with two equivalents of Bu"Li yielded a dilithio compound which reacts with (2,4,6- Me,C,H )(Bu')GeF to give the corresponding 1,3-diarsa-2-sila-4-germacyclobutane. Single crystal X-ray diffraction studies have been reported for (2,4,6-Pr\C,H,)(Bu')Si(AsH,) and the 1,3-diarsa-2-sila-4-germacyclobutane.The four- membered [SiGeAs,] ring in the latter is puckered with the two But groups orientated in mutually trans positions. loo N. Burford T. M. Marks P. K. Bakshi and T. S. Cameron Angew. Chem. Int. Ed. Enqf. 1994,33 1267. R. Ceaolivares J.G. Alvarado G. Espinosa-Perez C. Silvestru and I. Haiduc J. Chem. SOC.,Dalton Trans. 1994 2191. lo* M. Driess and H. Pritzkow Chem. Ber. 1994 127 477. K.K. Hii and T.P. Kee The halogeno-bis(dimethy1dithiocarbamato)compounds [As(DTC),X] (X = Cl Br I) have been shown to react with Me,SiOSO,CF to afford the ionic compounds [As(DTC ),][OSO,CF,] by condensation of Me,SiCl. IR spectroscopic and mass spectrometric investigations have also been reported.'O3 Primary and secondary unsaturated arsines vinylarsine isopropylarsine (E) and (2)-prop-1-enylarsine and divinylarsine have been synthesized according to Scheme 2.1°4The primary vinyl arsines are quite unstable at ambient temperature (half-life ca. 30 mins). AsC13 + R2HR'L R' R3 SnBu Scheme 2 Metal-containing Arsenic Compounds.-Ph,AsGaI has been prepared by reaction of Ph,As with GaI,.OEt in diethylether solvent and the structure solved by single-crystal X-ray diffraction. lo' The compound [Ph,AsI][GaI,] has also been prepared and characterized structurally by Raman spectroscopy (As-I stretching occurs at 196cm-') and by single-crystal X-ray diffraction. Indeed this salt appears to be the first arsenicfv) iodo complex to have been examined crystallographically and contains a [As-I] distance of 2.485(1)A.n The first gallacyclopentane [(CH,),Ga-p-AsBui] (44)has been synthesized in 61 % yield by the treatment of Li(CH,),Li with C1,GaAsBui in diethyl ether solvent.'06 The cobalt(1r) complex Co(CNCHMe2),(Ph,AsCH~CH2AsPh,),(CIO,) was syn- thesized by the reaction of Co,(CNCHMe2),,(C10,),.5H20with an excess of Ph,AsCH,CH,AsPh,. Solid state characterization is consistent with a six-coordinate tetragonal coordination in which the Ph,AsCH,CH,AsPh ligands are monoden- tate.' O7 R. Egle and A. Schmidt Z. Anorg. Allg. Chem. 1994 620 539. '04 J. E. Guillemin and L. Lassalle Organometallics 1994 13 1525. lo' L.J. Baker C.E.F. Rickard and M.J. Taylor J.Organomet. Chem. 1994 464 C4. A. H. Cowley S. Corbelin R. A. Jones R. J. Lagow and J. W. Nail J. Organomet. Chem. 1994,464 C1. lo' C. A. L. Baker Synth. React. Inory. Metal-Org. Chem. 1994 24 855. Nitrogen Phosphorus Arsenic Antimony and Bismuth 85 Arsine complexes of rhodiumtr) catalyse efficiently the transfer dehydrogenation of alkanes under an atmosphere of dihydrogen while at the same time producing lowered levels of direct hydrogenated sacrificial olefin relative to that derived from similar phosphine-based catalysts.'" Reactions of As,O with methanolic solutions of Fe(CO) have resulted in the formation of the anionic species [AsF~,H(CO),,]~ -which may be precipitated directly from solution as the [PPh,]+ salts.'09 The anion consists of a central arsenic atom surrounded by three [Fe(CO),] groups in a trigonal bipyramidal arrangement together with a bound hydrogen atom which was unfortunately not located directly by the X-ray diffraction experiment but inferred on the basis of charge considerations and by 'H NMR data.The 'H NMR spectrum exhibited a broadened singlet resonance at 6 1.34 ppm with a half-height width of ca.6 Hz. Attempts to synthesize the antimony analogue were successful but the bismuth derivative could not be obtained. The reaction of (rac)-(2-aminophenyl)(2-chlorophenyl)methylphosphine with sodium (2-dimethylarsinopheny1)methylarsenidehas been found to be completely stereoselective giving (rac)-l-[(2-dimethylarsinophenyl)methylarsino]-2-[(2-aminophenyl)methylphosphino]benzene (Scheme 3) as confirmed by the single-crystal X-ray diffraction analysis of a complex of this ligand with cobalt(rIr).' '' The reaction of [Fe,(CO),] with compounds of the form R,EX2 [R,E = Ph,P (4-MeOC6H,),P Me2PhP Me,As or Ph,Sb X = I; R,E = Ph,P Ph,As or Me,As X = Br] has been investigated and shown to yield diverse products.' '' A series of complexes with the ionic structure [R,EX][Fe(R3E)X3] [E = P R = Ph, Me2Ph or (4-MeOC6H,),P X = I; R3E = Me,As; X = I or Br] have been obtained.However the reaction of [Fe,(CO),] with Ph,AsBr resulted in the formation of the iron(rr1) complex [(Ph,As),Br][FeBr,]. Tetramethylarsoles RAsCMe=CMeCMe=CMe (R = Ph Me But) have been obtained from Cp,Zr(C,Me,) and RAsCl,. From these a number of complexes of the type M(CO),(arsole) (M = Cr W) cis-W(CO),L(arsole) (L = piperidine Pr',P) [CpMn(Co)(No)(arso1e)]-[pF6] [CpRu(PR3)2(arso1e)][pF6] [(PR3)2 = (PPh3)2 dppm dpme] and [Cp*RuL,(arsole)][PF6] (Cp* = C,Me,; L = (PMe,), nor-borna-2,5-diene] have been prepared.'I2 The complexes with R = Me Ph undergo Diels-Alder addition reactions with the dimethyl ester of acetylene dicarboxylic acid.The 7-arsanorborna-2,5-dieneintermediates in these processes are unstable and decompose into arene and arsinidine complexes. In similar vein 3-arsolenes R'AsCH,CMe=CR2CH (R' = Ph Me But Cl; R2 = H Me) are readily obtained from zirconocene butadiene complexes and RAsC1,. Alkylation with Me1 gives arsonium salts of the form [R'MeAsCH,CMe=CR2CH2]I (R1 = Ph Me But; R2 = H Me) treatment with sulfur affords the sulfides R' (S)AsCH,CMe=CR2CH (R' = Me But) whilst oxidation with Br or S02C12 results in ring ~1eavage.l'~ From chloroarsolene ClAsCH,CMe=CR2CH, substitution products R' AsCH,CMe= J.A.Miller and L. K. Knox J. Chem. Soc. Chem. Commun. 1994 1449. lo9 F. Henderson M. Rossignoli R. C. Burns M. L. Scudder and D. C. Craig J. Chern. Soc. Dalton Trans. 1994 1641. 'lo R.J. Doyle G. Salem and A.C. Willis J. Chem. Soc. Chem. Commun. 1994 1587. 'I1 H. P. Lane S. M. Godfrey C. A. McAuliffe and R. G. Prichard J. Chem. Soc. Dalton Trans. 1994,3249. W. A. Schenk and E. Voss J. Organomet. Chem. 1994,467,67. 'I3 W.A. Schenk and E. Voss J. Organomet. Chem. 1994 467 57. K.K. Hii and T.P. Kee racemic racemic (i) 3 Li THF H,O; (ii) Na THF MeI; (iii) 3 Li THF H20; (iv) Na THF 1,2-dichlorobenzene; (v) sodium (2-dimethylarsinophenyl) methyl arsenide THF Scheme 3 CR2CH2(R' = I H SPh OMe NMe,) as well as coupling products with [As-As] [As-0-As] and [As-S-As] units were synthesized.Also a number of arsolene complexes with the metals chromium molybdenum tungsten and ruthenium have been described. 5 Antimony Metal-free Antimony Compounds.-The reactions of pentachlorophenol and penta- chlorothiophenol with Ph,Sb results in the cleavage of the antimony-carbon bond and formation of Ph2SbOC,C1 which represents the first example of a [Sb-C] bond fission from a triarylstibine by an alcohol."4 Pentachlorothiophenol however fails to cleave the [Sb-C] bond from Ph,Sb.The reaction of R,SbBr with alcohols in the presence of sodium or triethylamine gives the corresponding dialkoxides (or thioalkoxides) which are monomeric and non-conducting in dichloromethane. The synthesis and structure of a polymeric iodoantimonate anion is described which is unusual in that the antimony(n1) centres are disordered within the octahedral interstices of a close-packed arrangement of iodines.' ' New antimony(v) 1,1,1,3,3,3-hexafluoroisopropoxideshave been prepared and characterized on the basis of elemental analysis IR NMR spectra and mass A. Asthana Indian J. Chem. Sect. A 1994 33 687. C. J. Carmalt N.C. Norman and L. J. Farrugia Polyhedron 1994 13 1655. Nitrogen Phosphorus Arsenic Antimony and Bismuth spectrometric data as being of the form Sb[OCH(CF,),], SbCl[OCH(CF,),], SbCl fOCH(CF,),] .OEt, SbCl [OCH(CF,),] ,.OEt, and SbCl [OCH(CF,),].OEt,.The IR and mass spectral data are consistent with monomeric species. These compounds react with pyridine to yield adducts of the composition SbC1,-,[OCH(CF,),],.Py (where n = 1-5) and these adducts have also been characterized by standard techniques.' Antimony(v) octaethylporphyrins with a-bonded antimony-carbon bonds have been synthesized; [Sb(OEP)R(OH)] '[PF,] -(R = Me Et) and [Sb(OEP)Me,] + [PFJ .'I7 These compounds were prepared by the reaction of [Sb(OEP)(OMe)(OH)]+[PF,]-with an excess of AIR or via reaction of [Sb(OEP)Cl] with an excess of AlMe,. The porphyrin compounds are remarkably stable to oxygen and moisture in comparison to Group 13 and 14 analogues.The 'H NMR spectra of the purphyrin compounds revealed characteristically low frequency alkyl resonances (6 -4.33 to -6.73 ppm) due to the ring current of the porphyrin ring system. The monophosphine antimony complex [SbI,(PMe,)] has been shown to be polymeric but the particular nature of the bridging iodide ligands between the antimony centres suggests that a better description would be as a polymer of dimers.' Along similar lines the reaction between SbBr and PEt affords the ionic complex [PHEt,] +[Sb,HBr,(PEt,),] -formed presumably by adventitious hydrolysis and characterized by single-crystal X-ray diffraction analysis. The anion contains the discrete dinuclear anion [Sb,Br7(PEt,),l2 -which possess a geometry best described as lying between the extremes of face-shared bioctahedral and vertex-sharing square-based pyramids.' Two dimeric antimony compounds [SbCl,(NHMe,)(p-OEt),] and [SbCl(NHMe,)(p-NBu'),] have been synthesized by the reaction of [SbCl,(NMe,),-,] with ethanol (x = 2) or NHBu' (x = 1) respectively.12' Both complexes contain coordinated dimethylamine ligands and intricate intermolecular association in the solid state. + The compounds [Sb,CI (NPMe ),I [SbCI,] -and [SbCI(NPPh )] ,[SbCI,] have been formed by the reaction of SbCl with the phosphorane iminato compounds [SbCl,(NPMe,)] and [SbCl,(NPPh,)] in acetonitrile solvent respectively which are themselves synthesized by reaction of SbCl with Me,SiNPR (R = Me Ph).',' The complex ionic compounds have been characterized by ','Sb Mossbauer spectroscopy and by single-crystal X-ray diffraction analysis.The structure consists of the expected octahedral [SbCl,] -anion and cations [Sb,Cl,(NPMe,),(CH,CN)] in which one + Sb"' atom and one SbV atom are bridged by the nitrogen atoms of the phosphorane iminato ligands. The structure of [SbC1(NPPh,)],[SbC1,1,.6CH3CNis also reported which contains centrosymmetric cations [SbCl(NPPh,)(CH,CN),];+ in which the antimony atoms are bridged by the iminato nitrogen atoms. S. L. Chadha J. Fluorine Chem. 1994,69 7. K. Y. Akiba Y. Onzuka M. Itagaki H. Hirota and Y. Yarnamoto Organometallics 1994 13 2800. 'I8 W. Clegg M. R. J. Elsegood V. Graham N. C. Norman N. L. Pickett and K. Tavakkoli J. Chem. Soc. Dalton Trans.1994 1743. 11' W. Clegg M. R. J. Elsegood N. C. Norman and N. L. Pickett J. Chem. Soc. Dalton Trans. 1994 1753. lZo A. J. Edwards,N. E. Leadbetter M. A. Paver P. R. Raithby C. A. Russell and D. S. Wright,J.Chem. Soc. Dalton Trans. 1994 1479. R. Garber J. Pebler K. Dehnicke D. Fenske H. Goesmann and G. Baum 2.Anorg. Allg. Chem. 1994 620 592; D. Nusshar R. Garbe F. Weller J. Pebler and K. Dehnicke ibid. 1994 620 67. 88 K.K. Hii and T.P. Kee In contrast to the trigonal bipyramidal geometry of SbPh,Br, the related biphenyl-2,2-diylphenylantimonydibromide has a distorted square pyramidal ar-rangement of ligands about antimony and is dimeric in the solid state.', Me Me , Me the (45) The novel benzobis(stibo1e) (45) has been synthesized from a bis-zirconacycle precursor and shown to crystallize in an orientation which places all three ring substituents in a syn ~rientation."~The complex stacks in such a way that the central phenyl rings of two adjacent [Sb,C,,] ring systems are nearly perfectly eclipsed.The electro-reduction of [SbBu'Cl,] in THF solvent affords tetrameric [SbBu'] which has been examined via electrochemical techniques.' 24 Synthetic and spectroscopic studies have been reported on a number of tris-(n-fluorophenyl)antimony(v)acetates (n = 3 4).' 25 Single-crystal X-ray diffraction studies have been carried out on [SbMe,(OSPPh,),] which contains the monodentate monothiophosphinato ligand and the related complex [S~P~,(S,ASM~,)].'~~ A number of benzene-1,2-dithiolato complexes of antimony have been examined' 27 along with tetrathiofulvalene com- plexes of antimony halides.' 28 The regioselective and diastereoselective additions of acetylenic and allenic organoantimony compounds to aldehydes has been reported.'29 Metal-containing Antimony Compounds.-The single-crystal X-ray diffraction study of ([Sb,(NCy),],Cu,) (Cy = cyclohexyl) has been reported and the compound shown to consist of a polyhedral cage complex in which two terminal [Sb,(NCy),12- ligands stabilize a central [Cu,] core which is essentially square-planar.' 30 The reaction of Na,Sb with Mo(bipy)(CO) (bipy = 2,2'-bipyridine) and 2,2,2-crypt(4,7,13,16,2 1,24-hexaoxa- l.l0-diazobicyclo[8.8.8]hexacosane) in ethyle-nediamine solvent results in the formation of [Na(2,2,2-crypt)] ,[Sb,Mo(CO),].' 31 The compounds MeSbCl and SbC1 react together to afford the adduct [Me(Cl),Sb.O.GSbCl,].It has been shown that MeSbBr reacts with NaI to give MeSbI and with Cr(CO),.THF to give Me(Br),SbCr(C0),.'32 "'M.N. Gibbons M. J. Begley and D.B. Sowerby J. Organomet. Chem. 1994,469 C25. D.P. Hsu B. P. Warner R. A. Fisher W. M. Davis and S.L. Buchwald Organometalhcs 1994,13,5160. Y. Mourad A. Atmani Y. Mugnier H. J. Breunig and K. H. Ebert J. Organomet. Chem. 1994,476,47. A. Ranjen A.K. Saxena and P.S. Venkataramani Indian J. Chem. Sect. A 1994 33 948. C. Silverstru 1. Haiduc K. H. Ebert H. J. Breunig and D. B. Sowerby J. Organomet. Chem. 1994,468 113;D. B. Sowerby,M.J. Begley M.J. Silaghidumitrescu I. Silaghidumitrescu and 1.Haiduc ibid. 1994. 469,45. J. Wegener K. Kirschbaum and D. M. Giolando J. Chem. Soc. Dalton Trans. 1994 1213. Y.I. Kim S.N. Choi and W. S. Jung Bull. Korean Chem. Soc. 1994 15 465. lZ9 L.J. Zhang X. S. Mo and Y. Z. Huang J. Organomet. Chem. 1994 471 77. D. Barr A. J. Edwards S. Pullen M. A. Paver P. R. Raithby M. A. Rennie C.A. Russell and D. S. Wright Angew. Chem. Int. Ed. Engl. 1994 33 1875. 13' U. Bolle and W. Tremal J. Chem. Soc. Chem. Commun. 1994 217. 13' H. J. Breunig M. Denker and K. Ebert J. Orgunomet. Chem. 1994 470 87. Nitrogen Phosphorus Arsenic Antimony and Bismuth 89 The reaction between SbCl and three equivalents of Na[Ni(C0)(q5-C,Me,)] affords the tri-nickel element complex (Sb[Ni(CO)(q5-C,Me,)]3).133 When only two equivalents of Na[Ni(CO)(q5-C,Me,)] are used the product formed is (SbC1[Ni(C0)($-C,Me5)],).6 Bismuth Compounds without Bismuth-Carbon Bonds.-Direct addition of BiC1 to [(PT~)~P(=S)], affords bright yellow crystals of the 1 1adduct Cl,Bi.([(Pr"),P(=S)] ,) which possesses a halide-bridged dimeric structure in which each bismuth atom is surrounded by an essentially octahedral arrangement of four chlorine atoms [two teminal Bi-Cl 2.500(5) 2.516(5) A and two bridging Bi-C12.653(4) 3.015(5) A] and two sulfur atoms [Bi-S 2.857(4) 2.973(4) A].'34 Each of the two ligand molecules is involved in bidentate (S,S')chelation to a bismuth atom to form a five-membered ring. The synthesis of the first water-soluble bismuth(r1r) porphyrin adduct bismuth(II1) tetrakis(N-methyl-3-pyridy1)porphyrinhas been reported.Kinetic studies indicate that while the removal of bismuth from this macrocycle is catalysed by protons major anion and hydroxide contributions are also present. Such strong anion catalysis has only been found before with indium(II1) and magnesium@) porphyrins and the hydroxide effect appears to be without precedent. In the presence of a mixture consisting of bismuth(II1) chloride and metallic zinc aromatic nitro compounds have been found to be selectively reduced inter- and intra-molecularly to the corresponding N-oxides at ambient temperature in high yields.' 36 The synthesis of common monodentate bismuthines and of polydentate compounds containing one or more donor bismuth atoms have been reviewed.' 37 The reaction of BiC1 or Bi(NO,),SH,O with three equivalents of KSCN affords a yellow material which has not been fully characterized but which nevertheless reacts as if it were a source of Bi(SCN)3.138 This material reacts with two equivalents of K[Mo(CO),(q5-C,H,)] to afford the green complex Bi(SCN)[Mo(CO),(q5-C5H5)].The same yellow 'Bi(SCN),' source reacts with KSeCN to afford Bi(SeCN) which reacts subsequently with two equivalents of Bi[Mo(CO),(q5-C,H5)] to afford Bi(SeCN)[Mo(CO),(q5-C5H5)].The reaction of N(PPh,),BiCl and four equivalents of KSeCN affords dark red crystalline KN(PPh,),Bi(SeCN),. The crystal and molecular structures of a range of bismuth(II1) dimethyldithiophos- phinate compounds has been investigated by X-ray diffraction.' 39 The complex [Bi(S,PMe,),] is a centro-symmetric dimer in which pentagonal-bipyramidal monomeric units are held together by secondary [Bi-..S] interactions.There is the possibility that the bismuth atoms in this dimeric complex could possess stereochemi- cally active lone pairs. The reaction of BiX (X = Cl Br I NO,) with Li,(Pc) (Pc = phthalocyaninate 133 N.C. Norman N. L. Pickett W.D. Storr N. M. Boag and A. J. Goodby Polyhedron 1994 13 2525. 134 G. R. Willey J.R. Barras M. D. Rudd and M. G. B. Drew J. Chem. Soc. Dalton Trans. 1994 3025. 13' G. P. Chacko and P. Hambright Inory. Chem. 1994,33 5595. H.N. Borah D. Prajapati J.S. Sandhu and A.C. Ghosh Tetrahedron Lett. 1994,35 3167. 13' N. R. Champness and W. Levason Coord. Chern. Rev.1994 133 115. A. Crispini R. J. Errington G.A. Fisher F. J. Funke N.C. Norman A.G. Orpen S. E. Stratford and 0. Struve J. Chrm. Soc. Dalton Trans. 1994 1327. 139 F.T. Elderman M. Noltemeyer I. Haiduc C. Silvestru and R. Ceaolivares,Polyhedron 1994 13 547. 90 K.K. Hii and T.P. Kee dianion C,,H,,Ni-) in a range of solvents including DMSO N,N-dimethylformam- ide MeCN and acetone results in the formation of [Bi(Pc)X] complexe~.'~~ In solution the bismuth atoms were found to be quite labile being expelled readily from the phthalocyanine ring by trace amounts of water acids or bases and could be replaced by a divalent metal upon addition of MSO (M = Co2+ Ni2+ Cu2+ and Zn2+). The electronic and IR spectra of the complexes [Bi(Pc)X] were found to be characteristic of metallophthalocyanines in general with the exception of an extra charge-transfer band in the electronic spectra of the former.The syntheses and structures of a number of bismuth(m) complexes of nitrilotriacetic acid ethylenediaminetetracetic acid and diethylenetriaminepentacetic acid have been reported. 41 The compound [BiCl,(DMSO),] has been prepared from a reaction mixture containing BiCl, Me,SiN(SO,Me), DMSO CH,Cl, and MeNO,. The crystal structure reveals octahedral coordination about bismuth with the DMSO ligands bound through their oxygen Three forms of bismuth phosphate have been synthesized and the resulting single phases characterized by thermal analysis IR spectroscopy and powder X-ray diffraction. Two of the phases may be obtained at room temperature one trigonal and the other rnono~linic.~~~ Tandem Mukaiyama Aldol and halogenation reactions have been shown to be catalysed by 5 mole-percent mixtures of BiCl,-l .5ZnI,.'44 Bismuth(II1) mandelate has been shown to catalyse the oxidative [C-C] bond cleavage of a series of styrene epoxides in DMSO to the corresponding aryl carboxylic acids.The reaction is accelerated in the presence of electron-donating groups substituted on the phenyl ring.'4s A good Hammett correlation of log kobsversus CJ has been obtained with a p value of -1.08. Compounds with Bismuth-Carbon Bonds.-Synthetic routes to the bismuth hetero- cycles [XBi(CH,CH,CH,),NR] (X = C1 Br I) via the corresponding Grignard reagents [(XMgCH,CH,CH,) NR] have been described.46 The eigh t-mem bered ring products were characterized by 13C NMR IR and Raman spectroscopies. The structures were presumed to be isostructural to the antimony analogue where the bismuth atoms display Lewis acidic behaviour and the complexes possess trigonal bipyramidal geometries with transannular [Bi --N] interactions. The 13C NMR shift values of the a-CH groups have been used to compute the relative electronegativities of Group 15 elements which are found to fall in the order N > Bi > P = As > Sb. The addition of BiBr to Bimes (mes = 2,4,6-Me3C,H,) in diethyl ether solvent afforded a high yield (86%) of Bimes,Br as yellow crystals. Subsequent reaction of Bimes,Br with Ph,PS,NH in a 1 1 molar ratio gives a quantitative yield of Bimes(S,PPh,) rather than the expected dimesitylbismuth compound.147 Crystal structure determinations have revealed that Bimes,Br has a trigonal bipyramidal 140 H.Isago and Y. Kagaya Bull. Chem. SOC.Jpn. 1994,67 383. 14' S. P. Summers K.A. Abboud S. R. Farrah and G. J. Palenik Inorg. Chem. 1994 33 88. 14' P.G. Jones D. Henschel A. Weitze and A. Blaschette Z. Anorg. Allg. Chem. 1994 620 1037. 143 B. Romero S. Bruque M. A.G. Aranda and J.E. Iglesias Inorg. Chem. 1994 33 1869. 144 C. Leroux H. Gaspardiloughmane and J. Dubac J. Org. Chem. 1994 59 2238. 145 V. Leboisselier E. Dunach and M. Postel J. Orgnnomet. Chem. 1994 482 119. 14' E. Brau R. Falke A. Ellner M. Beuter U. Kolb and M. Drager Polyhedron 1994 13 365. 14' K. H. Ebert R. E. Schulz H. J. Breunig C.Silvestru and I. Haiduc J. Orgnnomet. Chem. 1994,470,93. Nitrogen Phosphorus Arsenic Antimony and Bismuth coordination around the bismuth atom with [Bi * Bi] contacts of 3.795 A indicative of weak secondary bonding which gives rise to the observed zigzag shaped (Bi-Br)x chains. The compound Bimes(S,PPh,) is composed of discrete monomeric units each of which contains a mirror plane containing the bismuth atom and the aromatic ring of the attached mesityl group. The dithiophosphinato ligands exhibit an anisobidentate coordination pattern with long and short [P-S] bonds. This leads to a square pyramidal geometry around the bismuth atom with the latter lying above the basal plane formed by the four sulfur atoms.’48 The derivatives [(RC,H,)BiBr,] and [(RC,H,),BiCI] (R = 4-CH,.4-CF3 3-F 4-F) have been prepared from the redistribution reactions of the corresponding triarylbismuth compounds with BiBr and BiCl respectively.14’ Metathesis reactions of these compounds with [Cd(CF,),] yielded the new aryl(trifluoromethy1)bismuth compounds [(RC,H,) -nBi(CF3)n](n = 1and 2). The mono(trifluoromethy1) deriva- tives are quite stable towards dismutations whereas the bis(trifluoromethy1) com- pounds redistribute rapidly to afford [(RC,H,),Bi(CF,)] and [Bi(CF,),]. Compara- tive reactions of [(RC,H,) -nBi(CF3)n] with benzoylpyridinium chloride showed that the mixed derivatives transfer the phenyl group preferentially to yield benzophenone. A range of mixed bismuth-molybdenum complexes have been prepared and structurally characterized by the reaction of [BiPh,-,X,] (X = C1 Br) with Na/KCMo(rl 5-C5H5 )(CO)3I- 14’ N.V. Kirij S. V. Pasenok,Y. L. Yagupolskii,D. Naumann and W.Tyrra J. Fluorine Chem. 1994,69,219. 149 R. J. Errington,G.A. Fisher N. C. Norman A. G. Orpen and S. E. Stratford,Z. Anorg. Ally. Chem.,1994 620 451.

ISSN:0260-1818    

DOI:10.1039/IC9949100067

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

7 Oxygen Sulfur Selenium and Tellurium J. DEREK WOOLLINS Department of Chemistry Loughborough University of Technology Loughborough Leicestershire LE 1 7 3TU UK A number of significant reviews were published in 1994. A very good account of the properties and uses of Group 13 oxides and hydroxides' will be of wide interest. The importance of oxides in materials was highlighted. Thus there were reviews on the characterization of hybrid siloxane-oxide materials obtained from sol-gel processing,2 an account of volatile metallo-organic precursors for the deposition of inorganic electronic material^,^ as well as a discussion of heterometallic alkoxides and oxoalkoxides used in chemical routes (e.y. hydrolysis) to metal oxide^.^ Heavier Group 16 elements are also relevant in materials science and there were useful reviews on a number of topics.Several reactions have been described which illustrate how molecular reagents (e.g. M(ER) M = Zn Cd Hg E = S Se Te; R = alkyl aryl) can be transformed into extended inorganic solids.' An interesting paper on a related topic was presented at the American Chemical Society meeting.6 The growing interest in S-N-P polymers was well illustrated in an excellent review by manner^.^ Supposedly 'simple' systems also continue to be studied. Thus homo- and hetero-atomic Group 16 rings were reviewed.' There were also reviews on the coordination chemistry of PNS and PNSe rings/cages which demonstrate mono- di- tri- and tetra-dentate b~nding.~ The innovative recent work in Se-N and Te-N chemistry has also been summarized." There continues to be very substantial interest in the biological aspects of sulfur and selenium chemistry which largely falls outside the remit of this report.Typical examples include' ' the study of the degradation of thiosulfate and tetrathionate by Thiobacillus-intermedius. A NMR study of the interaction of platinum salts with tetrapeptide- containing cysteinyl residues' showed cis-Pt(NH,),Cl to coordinate (with displace- ' K. A. Evans 'Chem. Alum. Gallium Indium Thallium' 1993,248,ed. A. J. Downs Blackie Glasgow 1994. F. Babonneau Polyhedron 1994 13 1123. D. C. Bradley Polyhedron 1994 13 1111. L. G. Hubert-Pfalzgraf Polyhedron 1994 13 1181. ' M. L. Steigerwald Polyhedron 1994 13 1245. H.W. Roesky Abs. Am.Chem. Soc. 1994 208 174-INOR. ' I. Manners Coord. Chem. Rev. 1994 137 109. R. S. Laitinen P. Pekonen and R. J. Suontamo Coord. Chem. Rev. 1994 130 1. T. Chivers and R.W. Hilts Coord. Chem. Rev. 1994 137 201. lo A. Haas J. Kasprowski and M. Pryka Coord. Chem. Rev. 1994 130 301. S. Wentzien W. Sand A. Albertsen and R. Steudel Arch. Microhiol. 1994 161 116. '' N. Hadjiliadis N. Ferderigos J. L. Butour H. Marzarguil G. Gasmi and J. P. Laussac Inorg. Chem. 1994 33 5057. 93 94 J. Derek Woollins ment of the chloride) with the -S-CH groups of the tetrapeptide; upon coordination there is NH liberation as a consequence of the strong trans effect of the S-donor ligands. Studies on bioinorganic enzymes continue in many areas. For example a new analysis of the EPR and Mossbauer data in nitrogenase P-clusters suggested that each half of the cluster contains a 'classical' [Fe,S,] unit with one Fe"' and three Fe" sites + but that as a consequence of an additional serine ligand at one site the spin properties of the two halves are different.I3 The Ni" dinuclear site of urease (jack bean) has been studied by EXAFS with and without 2-mercaptoethanol.The 2-mercaptoethanol-containing dinuclear site is proposed to contain two Ni" ions bridged by the thiolate sulfur atoms of the thiols. l4 There was an interesting review on the role of selenium in micro- organism^,'^ furthermore there have been numerous reports on selenium in biological and/or environmental systems. For example supplementation of a normal diet with additional selenium was shown16 to modulate T-lymphocyte mediated immune responses in humans where the responses depend on signals generated by the interaction of interleukin 2.The use of two selenium-containing fertilizers has been evaluated,17 surprisingly the authors suggest that BaSeO provides an effective alternative to current strategies for supplying selenium to grazing animals. A study of contaminants in eggs in California showed that although selenium levels were supposedly high enough to cause reproductive problems no impairment was observed in these cases.I8 Studies on metallathionen levels in rats fed or injected with selenite showed that feeding the animals 5-9pg/g of Se as selenite had no impact whereas injections of 1.5 mg/g Se as selenite did increase metallathionen levels in the liver and kidney although not as markedly as when zinc is used." One can only hope that studies of this type provide some genuinely useful insights.Singlet oxygen chemistry continues to be of great interest both from fundamental and applied perspectives. Thus the singlet oxygen quantum yields from the triplet excited states of DNA and related molecules have been studied; interestingly for guanine-containing moieties no singlet oxygen was detected; some possible implica- tions relating to DNA photodamage were discussed.20 Ozonolysis of c60 generates a mixture of oxidized products with ketone ester and epoxide functionalities;2 one imagines that c60 would also react successfully with sg to give equally interesting products.The report of non-reactivity of C, with chemically generated singlet oxygen22 further serves to illustrate the chemical community's remarkable interest in C, chemistry; although no reactions with graphite were reported. Many other ozonolysis reactions have also been reported for example reactions with l3 J. M. Mouesca L. Noodleman and D. A. Case Inorg. Chem. 1994,33 4819. l4 S. Wang M. H. Lee R. P. Hausinger P. A. Clark D. E. Wilcox and R. A. Scott Inorg. Chem. 1994 33 1589. J. Heider and A. Boeck Ado. Microh. Physiol. 1993 35 71. l6 M. Roy L. Kiremidjian-Schumacher H. L. Wishe M. W. Cohen and G. Stotzky Biol. Truce Elem. Res. 1994 41 103. l7 B. R. Whelan D. W. Peter and N. J. Barrow Aust. J. Agric. Res. 1994 45 863. '' R.L. Hotherm and D. Welsh Arch. Enuiron. Contam. Toxicol. 1994 27 180. l9 C. L. Chen and P. D. Whanger J. Inorg. Biochem. 1994,54 267. 2o S. M. Bishop M. Malone D. Phillips A. W. Parker and M. C. R. Symons J. Chem. Soc. Chem. Commun. 1994 871. 21 M. Ripudaman S. Kumar and A. Satyam J. Chem. SOC. Chem. Commun. 1994 1339. 22 L. Juha V. Hamplova J. Kodymova and 0.Spalek J. Chem. SOC.,Chem. Commun. 1994 2437. Oxygen Sulfur Selenium and Tellurium ferro- and ferri-cyanides in the solid state have been discussed.23 Simple binary compounds continue to be worthy of study. Density function calculations on S,O indicate that there are numerous 'stable' cyclic structures although it is clear that S=O is preferable to S-0-S and that an S chair conformation is better than a boat c~nformation.'~ The structures of [HS,O,] -and [ClSO,] -have been calculated.SO and HS- should form a chain-like [HSSO,] -(exothermic by ca. 108 kJmol-') whilst SO + C1--+ [ClSO,]-is also exothermic (79kJmol-').25 A number of interesting metal oxygen systems have been reported. Cyclic metallasilozanes based on for example (Bu\)Si(OH) are readily prepared26 and a number of examples were characterized crystallographically. In related work the acyclic phosphazene ligand HN(P(NMe,),NSiMe,} was reacted with [NH,]VO to give the [VO,(SiMe,),]- anion in quantitative yield.27 The SiMe groups migrate from N to 0 centres in this reaction. Reaction of MoCI,(PMe,) with neutral sulfur donor ligands (e.g. SPPh,) gives Mo,(p-S)(p-Cl)(PMe,), formed via Mo(S)Cl,(PMe,), which undergoes a con-proportionation reaction with the starting material.28 The Mo-S distance in the Mo"'-Mo"' bi-octahedral product is 2.276( 1) A.The synthesis of terminal vanadium imido 0x0 sulfido selenido and tellurido complexes has been reported.29 Oxidation reactions both stoichiometric and catalytic have continued to excite interest. Thus CoCl,/acetonitrile was shown to be a good mimic for B12 for the conversion of sulfides into di~ulfides.~' New porphyrins containing electron-with- drawing p-substituents have been prepared the Fe"' complex was shown to be an excellent catalyst for the epoxidation of cycl~octene.~ Regioselective hydroxylation of phenols has been reported using a ~erium'~-calix(8)arene.~~ The use of palladium catalysts for the oxidation of allylic amines with molecular oxygen appears to be solvent dependent with Me,SO being especially useful., Rh salts have proved34 to be valuable for the selective transformation of saturated hydrocarbons into alkyl trifluoroacetates by treatment with H,O and CF,CO,H.A new ruthenium complex35 [R~O,(bipy)(I0,)(0H)~]l .5H20 has been characterized by X-ray crystallography (Figure 1) and shown to be an efficient catalyst for alkene epoxidation and the oxidation of primary and secondary alcohols to aldehydes and ketones respectively. Ruthenium was also used to catalyse the oxidation of chlorinated olefins by mon~persulfate~~ at room temperature and for the aerobic oxidation of alcohols.37 23 E. Reguera J.Fernandez-Bertran and J. Duque Polyhedron 1994 13 479. 24 R.O. Jones Inorg. Chem. 1994,33 1340. 25 K. Miaskiewicz and R. Steudel J. Chem. Soc. Dalton Trans. 1994 2919. 26 H. J. Gosink H. W. Roesky H. G. Schmidt M. Noltemeyer E. Irmer and R. Herbstirmer Organometallics 1994,13 3420. 27 S. K. Pandey H. W. Roesky D. Stalke A. Steiner H. G. Schmidt and M. Noltemeyer Phosphorus Sulfur Silicon Relat. Elem. 1993 84 231. K.A. Hall and R.J. M. Maye Inorg. Chem. 1994 33 3289. 29 C.C. Cummins R.R. Schrock and W. M. Davis Inorg. Chem. 1994 33 1448. 30 S. Chowdhury P.M. Samuel I. Das and S. Roy J. Chem. Soc. Chem. Commun. 1994 1993. 31 J. F. Bartoli P. Battioni W.R. De Foor and D. Mansuy J. Chem. SOC. Chem. Commun. 1994 23. 32 H. M. Chawla U. Hooda and V. Singh J.Chem. SOC.,Chem. Commun. 1994 617. 33 R.A. T. M. van Benthem H. Hiemstra J. J. Michells and W. N. Speckamp J. Chem.Soc. Chem. Commun. 1994 357. 34 K. Nomura and S. Uemura J. Chem. SOC. Chem. Commun. 1994 129. 35 A. J. Bailey W. P. Griffiths A. J.P. White and D. J. Williams J. Chem. Soc. Chem. Commun. 1994 1833. 36 M. Bressan L. Forti and A. Morvillo J. Chem. SOC. Chem. Commun. 1994 253. 37 S.Y. S. Cheng N. Rajapakse S.J. Rettig and B. R.James J. Chem. SOC. Chem. Commun. 1994 2669. J. Derek Woollins Figure 1 The X-ray structure of [RuO,(bipy){IO,(OH),~]~l SH,O Polytungstates were shown to be useful for the aerobic oxidation of H,S to Na[P,W,,O appears to give higher purity S than the iron complexes which are currently used commercially.The influence of S-N-0 species on the redox behaviour of Mn"'"' species has also been studied.39 Solid state catalysts have also been studied. Thus zeolites were used4' for the catalytic oxidation of arylamines to azoxybenzenes with H,O,. Direct hydrothermal synthesis was used to furnish a new large pore titanium silicate which is a useful catalyst for the selective oxidation of hydrocarbon^.^^ New 0x0 and dioxygen complexes have been reported. Thus the reaction of FeCl,/RNH/CO yields N-dialkylcarbamato complexes of Fe" such as { [Fe(O,(CNEt,),},]. Controlled hydrolysis of these compounds gave for example [{Fe(p,-O)(O,CNPr\),] which exists with two Fe tetrahedra face to face and an unusual (p40)bridge4 (Figure 2). Photolysis of [((Fe(edta)} ,014-gives oxygen and [Fe"(edta)12 -;this was rationalized by proposing a Fe"=O Intermediate.43 Stable peroxo complexes of osmium (Equation 1) were obtained by addition of 0 to [OsX(dcpe),]+ (X = C1 or H dcpe = 1,2-bis(dicy~lohexylphosphine)ethane).~~ [OsX(dcpe),] + 0 -+ truns-[OsX(O,)(d~pe)~] (11 + + Novel 0x0-persulfido tungstate complexes were reported from the reaction of WSi- with P2S,H,NNH,-2HC1 in CH,CN; WO(S,),{CH,C(=NH)NHNH} contains a terminal W=O two Si -ligands and a bidentate amidrazone ligand.45 Mono- oxomolybdenumIv dithiolato complexes have been prepared and studied as models for oxidoredu~tases.~~ Larger ring and cluster 0x0 complexes were also studied.Thus a 38 M.K. Harrup and C.L. Hill Inorg. Chem. 1994 33 5448. 39 F.F. Prinsloo J.J. Pienaar R. Vaneldik and H. Gutberlet J. Chem. Soc. Dalton Trans. 1994 2373. 40 H. R. Sonawane A.V. Pol. P. P. Moghe S. S. Biswas and A. Suydalai,J. Chem.SOC.,Chem. Commun. 1994 1215. " A. Corma M.T. Navarro and J. P. Pariente J. Chem. Sor. Chem. Commun. 1994 147. '* D. B. Dell'Amico F. Calderazzo L. Labella C. Maichel-Mossmer and J. Strahle J. Chem. Soc. Chem. Commun. 1994 1555. 43 H. Kunkely and A. Vogler J. Chem. Soc. Chem. Commun. 1994 2671. A. Mezzetti E. Zangrando A. Del Sotto and P. Rigo J. Chem. SOC.,Chem. Commun. 1994 1597. 45 S. Du N. Zhu and X. Wu Polyhedron 1994 13 301. 46 K. Yamanari M. Mori S. Dogi and A. Fuyuhiro Inorg. Chem. 1994 33 4807. 47 H. Oku N. Ueyama M. Kondo and A. Nakamura Inorg. Chem. 1994 33 209. '4 Oxygen Sulfur Selenium and Tellurium 97 Figure 2 The X-ray structure4' of [{ Fe4(p,-O)(0,CNPr!J,),1 systematic study upon M,[TeMo60,,].nH,0 [M = di- and tri-valent metals] has been reported.48 A range of doubly bridged dinuclear Co"' peroxo complexes were de~cribed.,~ metallacycle exhibits49 a A novel Mo,O,Cl,(~,-O),(~,-Eto)6(~2-cl)~ unique chair arrangement of the metal atoms with three Mo-Mo single bonds and two Mo,(p3-O) bridges.The reaction of ammonium vanadate with sodium molybdate in acidic aqueous solution followed by addition of morphine gives5' [Hmorph][Mo,V,- O,,]Cl which is built up of nine edge-sharing Mo octahedra with a random distribution of Mo and V atoms in the two 'capping' sites. The solid state reaction of [NH,],Mo7O2,.4H,O with [Bu,N]Br and NH,OH.HCl at 90°C gives [BU~N],[H,O]~[MO,,O~~]~ which contains two [MO,,O,,]~-anions with Keggin-type structures although the anions have different ~ymmetry.~' Other reports in this area include work on undecatungst~arsenates,~~ [Cp*TiMo,O 8] -,53 [M08026]4-,54 and [NaMO,O,,] -." The crystal structure of trans-VOCl,(H,O) hydrogen bonded adducts with two crown ethers have been compared,, the 0-V-0 angles were ca.153". Solid phase A. Saito Inory. Chim. Acta 1994 217 93. 49 C. Limberg S. Parsons and A. J. Downs J. Chem. SOC. Chem. Commun. 1994 497. B. Kamenar M. Cindric and N. Strukan Polyhedron 1994 13 2271. s1 X. Jin K. Tang H. Ni and Y. Tang Polyhedron 1994 13 2439. 52 J. Liu W. Wang G. Wang B. Zhao and S. Sun Polyhedron 1994 13 1057.53 H. Akashi J. Chen T. Sakuraba and A. Yagasaki Polyhedron 1994 13 1091. " M. McCann and K. Maddock Polyhedron 1994 13 835. s5 A.N. Startsev O.V. Klimov S.A. Shkuropat M.A. Fedotov S.P. Degtyarev and D.I. Kochubey Polyhedron 1994 13 505. 56 N. Azuma and T. Ozawa Polyhedron 1994 13 1715. 98 J. Derek Woollins condensation reaction of lead cyclophosphate was in~estigated.,~ An interesting spectroscopic study used boric acid trimethylester as a probe molecule in IR studies which enabled the Lewis base properties of MgO CaO ZrO, TiO, SnO, and Sb,O to be compared.58 Sulfur chemistry has advanced on a number of fronts. There was an interesting report on the synthesis of long-chain polysulfanes by the reaction of dialkoxysulfones (RO),S with thiol~.~' X-Ray and FT Raman studies were reported on [M,C1,]AsF6.The novel [ClS(Cl)SSCl) + and [ClSe(Cl)SeSeCl]+ cations were obtained6' by insertion reactions upon [MCIJAsF,. Radical formation has been described6' from the reaction of S,06F with S4N4 at sg the species formed are thought to be [S3N2]+ ' and [S,]". The solid state structure6' of S(NSiMe,) (which is isoelectronic with SO,) has been described; the (E)/(Z)configuration is preferred6 which is in contrast with previous gas-phase electron diffraction studies. A number of metal complexes of sulfur-containing ligands were reported. Oxidation of Mo(S,)(S,CNEt,) with rn-chloroperbenzoic acid gave the corresponding S,O complex which is S,S' ~oordinated.~~ Cyclooctasulfur adducts of WCl,.thf and WCl were also described.64 Insertion into M-SR bonds has been found to be a good route for the formation of MSSR complexes; the treatment of CpRu(PPh,)(CO)(SR) with RSphth (phth = phthalimido) giving C~RU(PP~,)(CO)(SSR)."~ The reactions of perfluorinated amines with sulfur compounds have also been investigated.66 The reaction of Me,SiNPPh with SOCl, SO,CI, and SCl gives [SO(Cl)NPPh,] [SO,(Cl)NPPh,] and [SClN(PPh,)]CI re~pectively;~~ from X-ray studies all three compounds appear to contain S=N and P=N.67 Related to this work was the report on the structure and NMR properties of bis(5,5-dimethyl-2-thioxo-1,3,2-dioxaphos-phorinan-2-y1)disulfide and diselenide.68 An interesting observation was made in the organic reaction between the thiocarbonyl group of monothiomaleimide and dienes namely that the C=S group appears to be a more reactive dienophile than electron-deficient C=C group^.^' The impact of Group 16 chemistry in the materials area has been well illustrated.For example PVC membrane solid state electrodes based on thioether have been shown to be highly selective for Ag' with low detection limits and short response A number of macrocyclic liquid crystals with functionalized thio-crown ethers have been '' G. Kura and T. Ueno Polyhedron 1994,13 3105. 58 C. Li S. Fu H. Zhang and Q. Xin J. Chem. SOC.,Chem. Commun. 1994 17. 59 R. Steudel and H. Schmidt Chem. Ber. 1994 127 1219. 6o P. Bakshi P. D. Boyle T. S. Cameron J. Passmore G. Schatte and G. W. Sutherland Inorq. Chem. 1994 33 3849.61 F. Mistry F.G. Herring A. Haas and F. Aubke J. Fluor. Chem. 1994,66 147. 62 M. Herberhold S. Gerstmann B. Wrackmeyer and H. Borrmann,1.Chem. SOC.,Dalton Trans. 1994,633. 63 M.A. Halcrow J. C. Huffmann and G. Christou Inorg. Chem. 1994,33 3639. 64 W. Baratt F. Calderazzo and L. M. Daniels Inorg. Chem. 1994 33 3842. 65 A. Shaver and P.Y. Plouffe Inorg. Chem. 1994 33 4327. 66 N. R.Patel R. L. Kirchmeier and J. M. Shreeve Inorg. Chem. 1994,33,4403. 67 H. Folkerts D. Nusshar F. Weller K. Dehnicke J. Magull and W. Hiller,Z. Anorg. A&. Chem. 1994,620 1986. 68 M.J. Potrzebowski G. Grossmann J. Blaszczyk M. W. Wieczorek J. Sieler P. Knopik and H. Komber Inorg. Chem. 1994 33 4688. 69 Y. Tamaru H. Sakata M. Kimura H. Harayama H. Konishi K. Fugami and S.Tanaka J. Chern. SOC. Chem. Commun. 1994 2365. 'O F. Teixidor M. A. Flores L. Escriche C. Viiias and J. Casabo J. Chem. SOC.,Chem. Commun. 1994,963. Oxygen Sulfur Selenium and Tellurium Figure 3 The X-ray str~cture’~ of one example of a low-coordinate zinc complex de~cribed.~’ An exciting development was the synthesis of thiol derivatized nanopar- ticles (1-3nm) of gold from (AuC1,)-/NaBH in the presence of an alkane thi01.~~ Aqueous sotutions of Cd,f /thiols/sodium hexametaphosphate were also found to form CdS colloids upon ultrasound irradiati~n.~ The chemical conversion of CdS films into Ag,S films by dipping thin films of CdS into AgNO was reported74. There also continues to be interest in new molecular materials. In this regard the formation of caesium tetrathiafulvalene-thiolates represents a significant advance.75 These caesium salts may be subsequently alkylated to give substituted TTF systems including a macrocycle which incorporates the TTF skeleton.A number of other papers on thiolates were of interest. Thus one investigated the evidence for n-bonding in boron-thiolates. A number of thiolato derivatives of Li Mg and Zn were described including a rare example77 of two-coordinate Li. Low coordinate chalcogenido complexes of zinc have also been reported by other workers78 (Figure 3) as well as a new group of complexes based on the Wurtzite frame~ork.~’ Other complexes prepared because of their potential electronic/magnetic properties include a range of maleonitrile systems,80 and tin 71 A.J. Blake D.W. Bruce I.A. Fallis S. Parsons and M. Schroder J. Chem. SOC. Chem. Commun. 1994 2471. 12 M. Brust M. Walker D. Bethell D. J. Schiffrin and R. Whyman J. Chem. SOC.,Chem. Commun. 1994,801. 73 R.A. Hobson P. Mulvaney and F. Grieser J. Chem. SOC.,Chem. Commun. 1994 823. 74 C.D. Lokhande and K. M. Gadave Mater. Chem. Phys. 1993 36 119. 75 J. Becher J. Lau P. Leriche P. Merk and N. Svenstrup J. Chem. SOC.,Chem. Commun. 1994 2715. 16 R. Wehmschulte K. Ruhlandtsenge M. M. Olmstead M. A. Petrie and P. P. Power J. Chem. SOC.,Dalton Trans. 1994 2113. 17 J. J. Ellison and P. P. Power lnorg. Chem. 1994 33 4231. 78 M. Bochmann G.C. Bwembya R. Grinter A.K. Powell K. J. Webb M. B. Hursthouse K. M.A. Malik and M. A. Mazid lnorg.Chem. 1994 33 2290. 19 D. H. Zen M. J. Hampden-Smith and E.N. Duesler Inorg. Chem. 1994 33 5376. SO J. V. Rodrigues I. C. Santos V. Gama R. T. Henriques,J. C. Waerenborgh M. T. Duarte and M. Almeida J. Chem. SOC.,Dalton Trans. 1994 2655. 100 J. Derek Woollins chalcogenides have been studied by several groups. A stabilization of terminal sulfido- and selenido- complexes was supported by ligation of the tin by the benzotetraaza[ 141 annulene dianion.8 Bis(tripheny1tin) chalcogenides were studied as precursors to SnS and SnSe. The (Ph,Sn),E compounds (formed from Ph,SnCl and Na,E) when heated to ca. 300 “Close Ph,Sn and Ph,E which are both volatile and thus the remaining solid is the binary sulfide or selenide.82 Another interesting reaction for tin was the treatment of tin powder with Me,SBr in diethyl ether which gives SnBr,(SMe,) with both cis and trans isomers in the unit cell.83 Much of the tin chemistry described above has also been applied to studies of germanium with thiolate complexes,84 terminal GeE systems* having been reported.Some related platinum complexes were also described.86 Lead trichalcogenide anions [Pb,SnE -,I2-(E = Se Te) have also been described.87 Indeed heavier main group systems appear to be gaining in interest with studies reported88 of thiocyanate and selenocyanate coordination to Bi”’ as well as89 Pb” complexes of [Ph,PS,I2 -. Transition metal complexes with sulfur-donor ligands also continue to be extensive- ly studied. A ‘tetranuclear’ Ag system was stabilized by [18]aneS,O coordinati~n.~~ The role of [RhMn(CO),(dppm),] in S-H bond activation was investigated9’ and examples of five-coordinate Re”’ with Skionor ligands were de~cribed.~’ Several sulfur/selenium containing clusters of note were described.A new Mo-W-S cluster complex family [{(OC),M)xM’S,]2- (M = Mo or W; M’ = Mo or W x = 1,2) has been de~cribed.~ Electrochemical studies on sulfur bridged ‘incomplete’ cubane-type Mo”/W” were compared with the X-ray structures for four new complexes.94 Binuclear Fe-Fe and Fe-Ru systems have also been described.95 Other (biologically important?) iron-sulfur clusters reported have in~luded~~Cp~(PhRC,S,),Fe,S, and (C5Me5)3(Ph2C2S,)Fe,S5 as well as Fe,S,L,(RNC) system^.^' Large cop-per/chalcogenide clusters still continue to excite interest.The energetics for a range of Cu,,Se,(PH,) systems have been studied by ab initio calculation^.^^ Mixed Mo and Cu-W selenium clusters were obtained from the reactions of [PPh,],[WSe4] with for example CUCN.~~ An extremely facile route to Rh Tr and M.C. Kuchta and G. Parkin J. Am. Chem. Soc. 1994 116 8372. 82 P. Boudjook D. J. Seidler S. R. Bahr and G.J. McCarthy Chem. Muter. 1994 6 2108. 83 N. Bricklebank,S. M. Godfrey C. A. McAuliffe and R.G. Pritchard J. Chem.Soc. Chem. Commun. 1994 695. 84 B. Kersting and B. Krebs lnorg. Chem. 1994 33 3886. 8s M.C. Kuchta and G. Parkin J. Chem. SOC., Chem. Commun. 1994 1351. R6 W. Baratta P. S. Pregosin A. Bacchi and G. Pelizzi Inorg. Chem. 1994 33 4494. ’’ M. Bjorgvinsson H.P.A. Mercier K. M. Mitchell G. J. Schrobilgen and G. Strohe lnorg. Chem. 1994,32 6046. ’’ A. Crispini R. J. Errington G.A. Fisher F.J. Funke N.C. Norman A. G. Orpen S. E. Stratford and 0. Struve J. Chem. Soc. Dalton Trans. 1994 1327. K. H. Ebert H. J. Breunig C. Silvestru I. Stefan and I. Haiduc lnorg. Chem. 1994 33 1695. yo A.J. Blake R. 0.Gould C. Radek and M. Schroder J. Chem. Soc. Chem. Commun. 1994 985. ” L.S. Wang R. McDonald and M. Cowie lnorg. Chem. 1994 33 3735. ” T. Maina A. Pecorale A. Dolmessa G. Bandoli and U. Mazzi J. Chem. Soc. Dalton Trans. 1994 2431. y3 B. Zhuang P. Yu L. Huang L. He and J. Lu Polyhedron 1994 13 125. 94 T. Shibahara M. Yamasaki T. Watase and A. Ichimura lnorg. Chem. 1994 33 292. ” T. Mitsui S. Inomata and H. Ogino lnorg.Chem. 1994 33 4934. y6 S. Inomata K. Hiyama H. Tobita and H. Ogino Inorg. Chem. 1994 33 5337. ” C. Goh J.A. Weigel and R.H. Holm lnorg. Chem. 1994 33 4861. ” S. Dehnen A. Schaefer D. Fense and R. Ahlrichs Angew. Chem. lnt. Ed. Engl. 1994 106 786. 99 R.J. Salm and J.A. Ibers lnorg. Chem. 1994 33 4216. Oxygen Sulfur Selenium and Tellurium Figure 4 The X-ray structure" uf(q,-C,Me,)Ru(p~RTeTeR)(pz-TeR)Ru(r,C,Me5) (R= Tol) Ga cubane-like clusters of Se and Te was found to be the reaction"' of E(SiMe,) IE = Se Te) with Cp*MCl,. Related to this was a study of the conversion of late transition metal sulfide complexes into metal-sulfur cubanes.'" In selenium chemistry there was a report on an HPLC method for the quantification of organo-selenium molecules'02 as well as a report on the synthesislo3 and X-ray structure of Al,(Se03),~3H,0.An unusual reaction was the report that camphor enolate reacts with selenium in thf to give the corresponding diselenidelo4 although different products are obtained in the presence of MeI. Ozonolysis of olefinic phenyl selenides followed by reductive work-up yields phenylseleno aldehydes and ketones with retention of the Ph-Se-group.lo5 Fundamental studies in P-Se chemistry included the X-ray structure of P4S4106n and of P2S5106b as well as a NMR investigation into P,Se,-,S,I(n = 0,1,2).lo7 loo S. Schulz M. Andruh T. Pape T. Heinze €1.W. Roesky L. Haming A. Kuhn and R. Herbstirmer Organometallics 1994 13 4004. lo' D.A. Dobbs and R.G. Bergmann Inorg. Chem. 1994 33 5329.lo' K. Gottfried K. Kalcher K. J. Irgolic and R. J. Magee Appl. Organornet. Chem. 1993 7 433. lo3 W. T. Harrison G. D. Stucky R. E. Morris and A. K. Cheetham Report 1992 Order No. AD-A251283 33pp. From Gov.Rep. Announce. Index (U.S.),1992,92 Abstr. No. 252445. Io4 T.G. Back B. P. Dyck and M. Parvez J. Chem. Soc. Chem. Commun. 1994 515. D.L. J. Clive and M. H. D. Postema J. Chem. SOC.,Chem. Commun. 1994 235. (a)R. Blachnik P. Loennecke and J. Nuss Z. Anorg. Allg. Chem. 1994 620 160; (h) R. Blachnik P. Loennecke K. Boldt and B. Engelen Acta Crystallogr. Sect. C Cryst Struct. Commun. 1994 50 659. lo' P. Loennecke R. Blachnik and B. W. Tattershall Z. Anorg. Allg. Chem. 1994 620 1115. 102 J.Derek Woollins Layered compounds KMP2Se6 (M = Sb Bi) which represent complexes of [P2Se6]4- have been prepared and studied.lo8 A novel coordination mode about tellurium was reported'" for [Ph,PS,] -.P-N-Se systems were also reported for example"' + [SeCl(NPPh,),] and 2,3-bis[2,4,6-tris(trifluoromethyl)phenyl]selenodiphos-phirane. '' New selenium- and tellurium-coordination compounds have included [Re,I,(CO),(Se),] ' ' [(C5Me,)Ru(p2-RTeTeR)(p,-TeR),Ru(C,Me,)] '' (Figure 4) and complexes of C,S,Se,-containing ligands.' l4 New low-dimensional quaternary compounds such as KCu,AsS,have been ob- tained from reactions in supercritical amine solvent,' l5 whilst solid state ,'Se NMR studies were reported on [M(Se4),l2- (M = Zn Cd Hg).'' Binary Se-N compounds continue to be studied although they must be considered to be difficult systems.A new preparation' l7of Se,N from SeO and Me,SiNPMe gave a different crystal modification to .the previously reported methods. IR spectra for binary Se-N compounds formed by the condensation of microwave discharge products were also reported; NSe and NSe being readily characterized at low temperature,' ' both [N(SC1)2]+,'19 and [N(SeCl)2]f'20.121 were further studied. An interesting acyclic122 N-P-Se anion K[Ph,P(Se)NSiMe,] was obtained from the reaction of Ph,P(Se)N(SiMe,) with KOBu'. With iodine the anion forms (Me,SiN)Ph,PSeSePPh,(NSiMe,). Other ternary P-N-S and P-N-Se systems have been further studied. Density function calculations were used to investigate' 23 the bonding in P,S,N4 systems whilst chalcogen substituted diazenes were reacted with zero-valent palladium and lead complexes to give' 24 M[PhEN(4-MeC6H,)CNNC(4MeC6H4)NEPh](PPh,) M = Pd Pt; E = S Se.The preparation of [Ph,P,N,S,R] -anions and their complexation' 25 and reaction with electrophiles' 26 have been described. A ruthenium complex of [Ph4P,N,S2I2 -was also Tellurium-containing chalcogen nitrides developed well in 1994.There were reports lo' T. J. McCarthy and M.G. Kanatzidis J. Chem. SOC.,Chem. Cornmun. 1994 1089. lo9 A.Silvestru 1. Haiduc K.H. Ebert and H.J. Breunig Inorg. Chem. 1994 33 1253. 'lo H. Folkerts K. Dehnicke J. Magull H. Goesmann and D. Fenske Z. Anorg. Allg. Chem.,1994,620,1301. l1 H. Voelker U.Pieper H. W. Roesky and G. M. Sheldrick 2. Naturforsch. Section B. 1994 49 255. '12 A.Bacchi W. Baratta F. Calderazzo,F.Marchetti and G. Pelizzi Angew. Chem. Int. Ed. Engi. 1994,106 206. '13 H. Matsuzaka T. Ogino M.Nishio M. Hidai Y. Nishibayashi and S. Uemura J. Chem. SOC.,Chem. Cornmun. 1994 223. ' l4 C. Faulmann J. P. Legros P. Cassoux J. Cornelissen L. Brossard M.Inokuchi and H.Tajima J. Chem. SOC.,Dalton Trans. 1994 249. '15 J.E. Jerome P.T. Wood W.T. Pennington and J. W. Kolts Inorg. Chem. 1994 33 1733. '16 P. J. Barrie R. J.H. Clark R. Withnall D.-Y. Chung K.-W. Woo and M. G. Kanatzidis Inorg. Chem. 1994 33 1212. H. Folkerts B. Neumuller and K. Dehnicke ZAAC 1994 620 1011. Its L. Andrews and P. Hassanzadeh J. Chem. SOC.,Chem. Commun. 1994 1523. 'I9 M. Broschag A.Schulz and T.M. Klapotke Chem. Ber. 1994 127 2187. lZo K.B. Borisenki M.Broschag I.Hargittai T. M. Klapotke D. Schroder A. Schulz H. Schwarz I. C. Tornieporthoetting and P. S. White J. Chem. SOC.,Dalton Trans. 1994 2705. 12' M. Broschag T. M. Klapotke A. Schulz and P. S. White Chem. Ber. 1994 127 2177. 122 T. Chivers M.Parvez and M.A.Seay Inorg. Chem. 1994 33 2147. lZ3 H. Jacobsen T. Ziegler T. Chivers and R. Vollmerhaus Cand. J. Chem. 1994 72 1582. lZ4 T. Chivers K. McGregor and M. Parvez Inorg. Chem. 1994 33 2364. lZ5 T. Chivers M. Edwards R.W. Hilts M.Parvez and R. Vollmerhaus Inorg. Chem. 1994 33 1440. 126 T. Chivers R.W. Hilts M. Parvez and R. Vollmerhaus Inorg. Chem. 1994,33 3459. 12' T.Chivers R. M. Hilts M. Parvez D. Risticpetrovic and K. Hoffman J. Organomet. Chem.,1994,480 C4. Oxygen Sulfur Selenium and Tellurium b Figure 5 The X-ray structure'33 of the [C,,Te,(C0,,J2-anion on the preparation' 28 of Cl,Te,N,S and Cl,Br,Te,N,S and also [C1TeNSNSI2 '[Cl] [AsF,] which contains a five-membered TeN,S ring.'29 The reaction of Ph,P(NSiMe,),Te(Cl)=NR (R = PPh,NSiMe,) with Bu'NHLi gives (Bu'NTeNR) which is a diimide dimer.' 30 A series of very weakly coordinated anions M(OTeF,) (M = As Sb Bi) has been described.' 31 New gold 132 and cobalt133 tellurides have been reported.[AuTe,,14- was obtained by ethylenediamine extraction of KAuBiTe alloy whilst [Co 1Te,(C0),o]2- (Figure 5)was prepared from CO,(CO) and Na,Te,. A. Haas and M. Pryka J. Chem. SOC. Chem. Commun. 1994 391. A. Haas M. Pryka and M. Schafers Chem. Ber. 1994 127 1865. I3O T. Chivers X.Gao and M. Parvez J. Chem. SOC. Chem. Commun. 1994 2149. 13' H. P.A. Mercier J.C.P. Sanders and G.J. Schrobilgen J. Am. Chem. SOC.,1994,116 2921. S. S. Dhingra and R. C. Haushalter Inorg. Chem. 1994 33 2735. 133 R. Seidel R. Kliss S. Weissgraber and G. Henkel J. Chem. SOC. Chem. Commun. 1994 2791. J. Derek Woollins A novel gallium tell~ride,'~~ [Ph,P]GaTe,(en), held together by NH-Te hydro-gen bonds has been obtained by cathodic dissolution of Ga,Te in ethylene diamine/[PPh,]Br. A one-dimensional telluride C,,Zr,Te,, was ~ynthesized'~~ at 900 "Cfrom Zr and Cs,Te,/Te this system contains numerous Te-Te interactions. A ternary zintl anion [Cu4SbTe,,13- was obtained'36 by solvent extraction upon KCuSbTe alloy. The structure consists of a tetrahedral Cu+ coordinated to SbTe:- and Te; -ligands.This report has described a few of my personal highlights in Group 16chemistry. It is evident that O/S/Se/Te chemistry continues to contribute to inorganic organic and materials chemistry in many ways. The breadth of work makes Group 16 a fascinating and often surprising part of the periodic table and this is doubtless sure to be true in future years. 134 C.J. Warren D. M. Ho R. C. Haushalter and A. B. Bocarsly J. Chem. SOC.,Chem. Commun. 1994. 361 13' J.A. Cody and J.A. Ibers Inory. Chem. 1994 33 2713. 136 S. S. Dhingra and R.C. Haushalter J. Am. Chem. SOC. 1994 116 3651.

ISSN:0260-1818    

DOI:10.1039/IC9949100093

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

The Halogens and Noble Gases By D.A. ARMITAGE Department of Chemistry King's College London Strand London WCZR ZLS UK 1 Introduction This chapter covers the 1994 literature and follows last year's format. 2 Halogens and Polyhalide Ions Laser ablated uranium atoms co-deposited with F and excess argon at 12 K onto a caesium iodide window have been found to give uranium(Iv) (v) and (VI) fluorides.' The use of lower laser energy gave compounds showing infrared bands at 400 and 446cm-' due to UF and UF, and at 496 and 561 cm-' which were tentatively assigned to UF and F3 .This latter pair of bonds also resulted from ClF and U atoms together with a new band at 554cm-' that was tentatively ascribed to ClF; . Iodine monofluoride generated in situ from iodide and elemental fluorine has been shown to react with arenes to provide a route to radiotracer substituted iodoarenes.Rotational spectroscopy has indicated the formation of a weak n-donor complex between ethylene and bromine monochloride supporting the traditional mechanism of alkene halogenation. The dimensions at ethene appear only to be weakly perturbed while NQR coupling constants are little changed from BrCl. This supports an un-ionized intermediate with BrCl perpendicular to the C=C bond as opposed to an ionized intermediate in the vapour phase. A theoretical study of the bromination of an alkene in solution has provided evidence that there is at least as much positive charge at bromine as at the two carbon atoms of the bromonium ion both in vacuum and in s~lution.~ Reacting Ph,As directly with iodine and recrystallizing from ether has been shown to give orange cubic crystals of the adduct with C symmetry and a propeller structure in which the As-I bond length is 261.6pm and the 1-1 distance 301.4pm.Ph,As-I as orthorhombic and monoclinic purple-red crystals has been shown to result from heating Mn(OAsPh,),I,.(SO,) to 100 "C and subliming the generated Ph,As-I,. These crystals have longer As-I bonds and shorter 1-1 bonds (300.5 pm) than the cubic form.5 Iodine has been found to promote the decomposition of l-aryl-3,3-dialkyltriazenes ' R. D. Hunt C. Thompson P. Hassanzadeh and L. Andrews Inorg. Chem. 1994 33 388. 0. Thinius K. Dutschka and H. H. Coenen Tetrahedron Lett. 1994 35 9701. H. 1.Bloemink K. Hinds A. C. Legon and J. C. Thorn Angew. Chem. Int. Ed. Engl. 1994 33 1512. M. Cossi M. Persico and J. Tomasi J. Am. Chem. Soc. 1994 116 5373. S. Abbas S. M. Godfrey C. A. McAuliffe and R. G. Pritchard Acta Crystallogr. Sect C 1994 50 717. 105 D. A. Armitage to aryl iodides at 80 "C in very good yield (Equation 1).6 Me,SiI was shown to reduce VCl,(MeCN) to [V(MeCN),]2'[I,]2- with the linear anion having a centre 1-1 bond (286.4pm) shorter than the two unequal terminal ones (316.6 and 351.6pm). It could therefore be conveniently considered as iodide and tri-iodide. 3 Interhalogen Compounds The pyridine complex of iodine monochloride C6H,NICl has been found to readily substitute phenols and anilines to give the para-iodo derivative in good yield (Equation 2).Disubstitution also occurs and heterocycles react similarly.' R I ROOH 0 GNHI ___c aq.MeOH ~~.ACOH c--,,,' I R ICI I 4 Cationic Organoiodine Alkynyl(pheny1)iodonium salts [RC-CIPh] readily add to cyanocarbonyl com- + plexes to give the intermediate isocyanovinylidene complex (Equation 3). This rearranges through R group migration (R = H SiMe, or Ph) to give the alkynyl isocyanide or through C-H insertion (R = But)to give the coordinated cyclobutenyl isocyanide (Equation 4).' The spiro bis(cyc1opentene) system (I) results from bis[phenyl(iodonium)]diyne triflate salts with nucleophiles such as diones or tosylate through double carbene formation and loss of iodobenzene. Diynes with longer polymethylene chains were shown to give coupled cyclopentenes (Equation 5).'O Alkenyl(pheny1)iodonium triflates have been shown to be formed from the reaction of cyano(pheny1)iodonium salts and the corresponding vinylstannane.The reaction is stereodefined with retention of the vinylstannane geometry (Equation 6).' Adding the carbene (2) to the iodoimidazolium salts (3) gives the bis(carbene) iodine adduct as colourless crystals (Equation 7) which possess an almost linear C-I-C skeleton with C-I bond lengths of 228.6 and 236.3 pm. With an electron withdrawing substituent such as pentafluorophenyl bonded to iodine the imidazole-iodine bond length is Z. Wu and J.S. Moore Tetrahedron Lett. 1994 35,5539. ' P.B. Hitchcock D. L. Hughes G. J. Leigh J.R. Sanders J. de Souza C. J. McGarry,and L. F. Larkworthy J. Chem. SOC.,Dalton Trans. 1994 3683. H.A. Muathen J. Chem. Res. (S) 1994 405. R. Kunz and W. P. Fehlhammer Angew. Chem. Int. Ed. Engl. 1994 33,330. lo R. R. Tykwinski P. J. Stang and N. E. Persky Tetrahedron tett. 1994 35,23. R. J. Hinkle and P. J. Stang Synthesis 1994 313. The Halogens and Noble Gases R - [M(CN)(CO)&+ [flC=CIPhr (OC)&l-C~N-C~ M =Cr W c"IPh I-PhI (3) (5) 'Nu R' CHpC12,-23" C " & + PhkNX-Bu3SnCN * f12)=\+IPhX (X=OTsorOTf) R2 SnBu rnes mes rnes rnes [:) [:+-:-(:I + I+!] X 3 X (X= I,BPh,) rnes rnes mes mes 108 D.A. Armitage shortened to 215.9 pm (N-substituted with adamantyl) and the I-aryl bond lengthened to 275.4~m.l~ (C6F5),T+ has been shown to be linear with C-I bond lengths of 233.1 and 232.4pm.N-(1odomethylene)piperdinium iodide (4) has been shown to result from the chloride using Me,SiI at 0°C. The yellow needles so formed adopt an almost linear C-1-1 structure with C-I bond lengths of 206.3pm to 213.2pm within the four- molecule asymmetric unit and the 1-1 distances of 333-344pm. The C-I bonds are longer than vinylic C-I bonds while the 1-1 distance is the arithmetic mean of the single bond (266pm) and van der Waals interaction distance (430pm). This structure corresponds to the 'frozen transition state' of I elimination from a donor stabilized di-iodomethane. It is further stabilized through intermolecular interaction between the terminal iodine and the p orbital of the carbenium centre (Equation 8).13 2Me$ iI I' e CH2CI2.0" C H 5 Organoiodine-Oxygen Compounds Acetates Trifluoroacetates and Triflates Iodosylbenzene PhIO has been shown to crystallize with a polymeric zigzag structure involving almost linear 0-1-0 bridges with 1-0 bond lengths of 206 and 238 pm.The related imido compound PhINS0,-p-tolyl has a similar structure with N-1.-N units.I4 With Ar3M (M = Sb Bi) iodosylbenzene was found to react under ultrasound to give the MV oxide which for M = Bi reacts with anhydrides to give the dibenzoate or carbonate (Equation 9).15 Chiral (sa1en)Mn"' has been shown to provide for the asymmetric induction in the oxidation of aryl methyl sulfides using PhT0.I6 With PhI(OAc), hydroxybenzoquinones are converted into 2-cyclopentene-l,4- diones via the phenyliodonio- 1,4-benzoquinone,' and semicarbazones have been found to oxidize to the parent ketone in wet acetonitrile.18 Heating PhI(OAc) with iodine gives the acetyl hypoiodite MeC(0)OI which with an alcohol forms the alkyl hypoiodite ROI.This photolyses to the alkoxy radicals." This has been used for the excision of the keto bridge in tricycloundecanones and tricyclododecanones.20 With l2 A. J. Arduengo 111 M. Tamm and J. C. Calabrese J. Am. Chem. SOC. 1994 116 3625. l3 R. Weiss M. Rechinger and F. Hampel Angew. Chern. Int. Ed. Engl. 1994 33,893. 14 C. J. Carmalt J.G. Crossley J. G. Knight P. Lightfoot A. Martin M. P. Muldowney N. C. Norman and A.G. Orpen J.Chem. Soc. Chem. Commun. 1994 2367. H. Suzuki T. Ikegami and Y. Matano Tetrahedron Lett. 1994 35,8197. K. Noda N. Hosoya R. Irie Y. Yamashita and T. Katsuki 7etrahedron. 1994 50 9609. " I. Papoutsis S. Spyroudis and A. Varvoglis Tetrahedron Lett. 1994 35,8449. D. W. Chen and Z. C. Chen Synthesis 1994 773. I') J. L. Courtneidge J. Lusztyk and D. Page Tetrahedron Lett. 1994 35 1003. '"J. Oh J. Lee S.-j. Jin and J. K. Cha Tetrahedron Lett. 1994 35,3449. The Halogens and Noble Gases fluorinated thiophenols in pyridine the bis(ary1thio)iodobenzene results which with alkynes gives bis(ary1thio)alkenes (Equation Phenyliodine (111) bis(trifluor0acetate) (PIFA) PhI(OCOCF,) has been used for the direct azidation of p-alkyl anisoles using Me,SiN (Equation 11),22 while with pyridinium polyhydrogen fluoride (PPHF) fluorine addition to 4-alkyl phenols occurs ips0 to give the enone (Equation 12).23 o-Iodobenzoic acid (IBA) readily adds bis(trimethylsily1)acetylene through the intermediate sulfonate to give the alkynyl iodonium salt (Equation 13).24 0 "=2 R = CF, p -tolyl Me IBA has been found to oxidize alcohols to aldehydes and ketones and 1,2-diols to the a-ketol or a-diketone without C-C cleavage of the glycol and as the phos- phorylated derivative can be converted into a range of derivatives substituted at the 21 Y.Kita T. Okuno H. Tohma S. Akai and K. Matsumoto Tetrahedron Lett. 1994 35,2717. 22 Y.Kita H. Tohma T. Takada S. Mitoh S. Fujita and M. Gyoten Synlett 1994 427. 23 0.Karam J.C. Jacquesy and M. P. Jouannetaud Tetrahedron Lett. 1994 35,2541. 24 V.V. Zhdankin C. J. Kuehl J. T. Bolz M. S. Formaneck and A. J. Simonsen Tetruhedron Lett. 1994,35 7323. 110 D.A. Armitage I-OH bond. These include the anhydride and t-butyl peroxy derivatives (Equation 14).25 The azido derivatives result from IBA and Me,SiN, while the bis(tri- fluoromethyl) derivative (5) can be similarly substituted (Equation 15).26 Both iodine(Ir1) azides are thermally stable crystalline solids. 0 I OOCMe OP(O)(OPh) Y3 Me3SiN3,CH2CI2* 0;;. 25" C 8-12h. \ CF cF3 A range of mixed diary1 triflates have been obtained as crystalline solids from the reagent formed from the reaction of (diacetoxy)iodobenzene and triflic acid with a range of arenes (Equation 16).27 The compound CF,CH21C12 has been formed from the iodide (CF,CH,I) and chlorine.It can be easily trifluoroacylated with AgOCOCF, triflic acid and benzene giving the mixed derivative (6). This readily trifluoroethylates a range of amino alcohols derived from amino acids such as alaninol prolinol ephirdine and phenylglycinol. Substitution occurs at nitrogen (e.g. prolinol-Equation 17).28 Reacting either PhI(OAc) or (PhIO) with N-heteroarenes (L) in the presence of Me,SiOTf has been shown to give a range of substituted aryl(111) triflate salts ArILlOTf-. They are much more reactive than the oxide or acetate and readily oxidize monohydrazones to diazo compounds and 1,2-bishydrazones to alkyne~.~~ 25 M. Frigerio and M. Santagostino Tetrahedron Lett.1994,35,8019;R. A. Moss and H. Zhang J. Am. Chem. Soc. 1994 116 4471. 26 V.V. Zhdankin,C.J. Kuehl A. P. Krasutsky M.S. Formaneck and J.T.Bolz Tetrahedron Lett. 1994,35 9677. '' T. Kitamura J.-i. Matsuyuki and H. Taniguchi Synthesis 1994 147. 28 V. Montanari and G. Resnati Tetrahedron Lett. 1994 35 8015. 29 R. Weiss and J. Seubert Angew. Chem. Int. Ed. Engl. 1994 33 891. The Halogens and Noble Gases 6 Oxides The symetric ClO radical has been furnished from the vacuum flash pyrolysis of chlorine perchlorate Cl,O,. The C1-0-C1 angles are 113.5" and the bond lengths 150pm. The angles and C1-0 force constant are smaller in ClO,. Photolysis gives the isomeric OClOO radical which forms the OCl-O van der Waals complex after photolysis ceases.,' The compound Br,O (synthesized from bromine and ozone) has been shown to form as an orange crystalline solid and on further ozonization gives a colourless oxide which does not contain the coloured O-Br(I) unit.It is insoluble in CH,Cl, unlike Br,O, and decomposes above -40 "C. However it can be stabilized by crystallizing from propionitrile and the structure determination shows symmetric 0,Br-0-BrO to be present. The molecule has terminal bonds (162pm) which are shorter than the bridging ones (187-189pm). The bond angle at the bridging oxygen atom is 121°.31 This study brings into doubt the existence of Br204 which appears to have a Raman spectrum very similar to that of Br203. (IO),SO has been shown to hydrolyse to a powder formulated as I,O which is monoclinic and thought to have a one dimensional structure comprising alternating oxygen bridged iodine(1) and iodine(v) units -1-0-10,-0-(I-0-10,-0)"-I-0-10,-0- (Equation 18).It decomposes on heating to diiodine pentoxide and iodine (Equation 19)., The mixed sulfate/selenenate (TO),(SO,) -,(SeO,) results from the reaction of 12/1205 with a mixture of sulfuric and selenenic acids., The compound 1205has been reported to desilylate Ph,PNSiMe (7) in acetonitrile to give the imino iodine(v) derivative Ph,P=NIO which has a N-I bond length of 191.8pm and 1-0 bond lengths of 176-181 pm. With iodine (7) gives a 1 1 complex the structure of which comprises a linear N-1-1 unit in which the N-I bond length is 243.2pm and the 1-1 bond length 283.3 prn., Olefins have been shown to be readily epoxidized using Bu:N+IO in the presence of Mn(r1r)porphyrin with imidazole as catalyst.7 Xenon Compounds Xenon difluoride readily gives a range of mononuclear and dinuclear osmium carbonyl fluorides using Os,(CO), in HF as solvent. The main product is cis-Os(CO),F which is stable in solution but removal of the solvent results in CO loss to give the fluoride bridged tetramer [OS(CO),F,],.~~ Phosphorus(rI1) acid derivatives are readily '"H. Grothe and H. Willner Angew. Chem. Int. Ed. Engl. 1994 33 1482. 31 D. Leopold and K. Seppelt Angew. Chem. Int. Ed. Engl. 1994 33 975. 32 H. Fjellvag and A. Kjekshus Acta Chem Scand. 1994 48 815. 33 M.A. K. Ahmed H. Fjellvag and A. Kjekshus Acta Chem Scand.1994 48 537. 34 D. Nusshar F. Weller and K. Dehnicke 2.Anorg. Allg. Chem. 1994 620 329. 3s D. Mohajer and S. Tangestaninejad Tetrahedron Lett. 1994 35 945. 36 S.A. Brewer J.H. Holloway and E.G. Hope J. Chem. Soc. Dalton Trans. 1994 1067. D.A. Armitage fluorinated using XeF to give either the phosphorus(v) monomer or the ionic salt (Equations 20 and 21).37 Oxidatively coupling R,Se (R = Ph biphenyl alkyl) to unsymmetrical disub- stituted acetylenes and cycloalkynes using XeF has been found to give the vicinal (E)-fluoroalkenyl selenides in high yield. Alternatively the PhSeF equivalent can be formed from PhSeSiMe and XeF,.38 Benzaldehydes furnish the difluoromethoxy benzene derivatives in good yield using XeF and HF in CH,Cl (Equation 22) while thioesters and thiocarbonates have been fluorinated at the C=S bond using Bu:N+H,F; .39 a-Unsubstituted pyrroles are easily substituted to give the fluoropyrroles in 25-54% yields using XeF (Equation 23).40 XeF,and HF ArCHO ArOCF2H CH&I Arylxenon(r1) tetrafluoroborates have been shown to result from Ar,B and XeF, the parachlorophenyl derivative decomposing at about 0 oC.41No such reaction occurs between XeF and arylsilanes or stannanes.The reaction of XeF with trifluoroacetic acid at -20 "C gives Xe(OCOCF,) which further exchanges 1 :1 with trifluorosul- fonic acid to give Xe(OCOCF,)(O,SCF,). This derivative with fluorobenzenes or trifluoromethylbenzenes gives the arylxenon trifluoromethylsulfonates as colourless solids4 The 2,6-difluorophenylxenon(r1) tetrafluoroborate was found to crystallize as an ion pair with Xe-F distance of 279.3 pm some 70pm shorter than the van der Waals interaction distance.43 8 Fluorobenzenes The amide dimer [(Me,Si),NLi] has been found to readily complex with fluoroben- zenes through their fluorine substituents.Monofluorobenzene and 172-difluoroben- 37 S.A. Lerrnontov,A.V. Popov S.I.Zavorin 1.1.Sukhojenk0,N.V. Kuryleva,l.V. Martynov,N. S.Zefirov and P. Stang J. Fluorine Chem. 1994 66 233. 38 H. Poleschner M. Heydenreich K. Spindler and G. Haufe Synthesis 1994 1043. 3y S. Stavber Z. Koren and M. Zupan Synlett 1994 265; M. Kuroboshi and T. Hiyama ibid. 1994 251. '"J. Wang and A. I. Scott Tetrahedron Lett. 1994 35 3679. " D. Naumann H. Butler R. Gnann and W.Tyrra Inorg. Chem. 1993,32,861;D. Naumann W. Tyrra and D. Pfolk Z. Anorg. Allg. Chem. 1994 620 987. '2 D. Naurnann W. Tyrra R. Gnann and D. Pfolk J. Chem. Soc. Chem. Commun. 1994 2651. 43 T. Gilles R. Gnann. D. Naurnann and K.-F. Tebbe Actu Crystallogr. Sect. C 1994 50 411. The Halogens and Noble Gases zene give 1 1 complexes in which the Li,N plane and that of the fluorobenzene are coplanar with linear C-F-Li interactions and F-Li distances of 186.6 and 189.4pm respectively. With 1,6difluorobenzene a linear polymer results with longer F-Li interactions of 199.1 pm (Equation 24).44 Pentafluorobenzoic acid C6F,C0,H can be readily o-defluorinated using Cp,Yb(DME) and activated magnesium to give tetrafluorobenzoic acid almost quantitatively (Equation 25).45 [(Me3Si),NLiI2 + FeF (Me3Siomitted for clarity) F F A variety of trimethylsilyl ethers have been shown to react with hexafluorobenzene to give the mono to hexapolyfluoroalkoxybenzenes and polyfluoroaryloxybenzenes.The structure of C,(OCH,CF,)6 shows that the c606 unit is planar but that the CH groups do not alternate above and below this plane. The perfluoro ether C,F,OCF,CF was shown to result from C,F,OCH,CF by chlorination and subsequent fluorination using SbF,/SbCl .46 Fluoride catalyses the coupling of a range of fluoroalkoxysilanes with a variety of electrophiles at 70 "C notably (Me,SiOCH,CF,) with 1,4-dibromotetrafluorobenzene to give (8) while with 1,2-diiodotetrafluorobenzene,(9) results (Equation 26).47 44 P.G.Willard and Q.-Y. Liu J. Org. Chem. 1994 59 1596. 45 G. B. Deacon C. M. Forsyth and J. Sun Tetrahedron Lett. 1994,35 1095. 46 Y. F. Zhang R. L. Kirchmeier and J. M. Shreeve J. Fluorine Chem. 1994 68 287. 47 N. R. Patel J. Chen Y. F. Zhang R. L. Kirchmeier and J. M. Shreeve Inorg. Chern. 1994 33 5463 D. A. Armitage 9 Hypohalites Passing fluorine through a solution of methanol in acetonitrile has been shown to give methyl hypofluorite which generates the novel electrophilic methoxylium cation MeO' .It reacts with a range of olefins with good regioselectivity while stereoselectiv- ity tends to be anti (Equation 27).48 With allene and trifluoromethyl hypofluorite a double addition occurs below room temperature to give mainly the 1,3-bis-trifluorornethoxylatedderivative though a small amount of the 2,3-derivative is also formed (Equation 28).49 Methoxyallene has been polymerized in the presence of CF,OF as initiator.Bromochloramines result from the bromination of monochloramine in aqueous solution in which the active species are BrZ,Br, hypobromous acid and the hypobromite ion. NBr,Cl has been shown to have a half-life of about 5 minutes at ~H6.2.~' OCF3 12h I H2C=C=CH2 + CF3OF -CH2CFzCH2 + H2CFCF (OCF3)CH@CF3 + CF4 (28) -100" c to -10" c I OC F3 48 S. Rozen E. Mishani M. Kol and I. Ben-David J. Org. Chem. 1994 59 4281. 49 T. Arimura S. Kurosawa and A. Sekiya J. Chem. Res. (S) 1994 202. M. Gazda and D. W. Margerum Inorg. Chem. 1994 33 118.

ISSN:0260-1818    

DOI:10.1039/IC9949100105

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

9 Zinc Cadmium and Mercury By I. B. GORRELL School of Chemistry and Molecular Sciences University of Sussex Falmer Brighton BNl SQJ UK 1 Introduction This chapter is mainly concerned with the organometallic and coordination chemistry of the title elements. However compounds containing macrocyclic ligands (excluding porphyrins) or open-chain polydentate ligands are not covered here unless there is a description of reactivity at the metal centre. Compounds consisting of extended frameworks are also excluded and the role of these elements in organic synthesis and in biological chemistry receives no mention although some models for biological systems are included. Papers on more than one element are cited under the lighter element unless the emphasis is on the heavier element.2 Zinc The stereodynamics and ligand exchange in solutions of tetrahedral chelate complexes of zinc cadmium and mercury have been reviewed.' Carbondonor Ligands.-Solid state 13C NMR studies have suggested a y3-allyl structure for 2-methylpropene when adsorbed on ZnO. Zincates of the type [Li(tmta),] [ZnRtR2] containing trigonal planar zinc have been prepared from ZnRi and LiR2 (R' = CH,SiMe, CH(SiMe,), CH(SiMe,CH,),SiMe,; R2 = Me Ph) in the presence of tmta. The amides [Li(trnta)(p-N(SiMe3),)Zn(CH,SiMe3),] and [ZnN(SiMe,),CH(Me,Si),] were also rep~rted.~ Reaction of (Me3Si),CLi.2THF with ZnCl in THF/Et20 gave Li[Zn,C13{C(SiMe3)3}2].2THF.Et,0. This reacted with RLi (R = Me Bun CH(SiMe,), C(SiMe,), Ph mes N(SiMe,), NHPh) to give (Me3Si)3CZnR.4 The compounds (1) have been prepared by reaction of the corresponding dilithium derivatives with ZnCl (R' = R2 = R3 = R4 = H; R' = Me R2 = R3 = R4 = H; R2 = Me R' = R3 = R4 = H; R' = R4 = Me R2 = R3 = H; R1 = R4 = H R2 = R3 = Me; L = Et,O tmeda dme).' Nitrogen-donor Ligands.-Porphyrins and Phthalocyanines.The crystal structure of the ' V. I. Minkin L. E. Nivorozhkin and M. S. Korobov Russ. Chem. Rev. 1994 63 289. A. A. Kheir T. Howard and J. F. Haw J. Am. Chem. SOC. 1994 116 10839. ' M. Westerhausen B. Rademacher W. Schwarz and S. Henkel Z. Naturforsch. Teil B 1994,49 199. M. Westerhausen B. Rademacher W. Schwarz J. Weidlein and S. Henkel J.Organomet. Chem. 1994,469 135. H.-0. Frohlich B. Kosan B. Undeutsch and H. Gorls J. Organomet.Chem. 1994 472 1. 115 116 I.B. Gorrell pyridine adduct of a zinc porphyrin trimer in which the porphyrin rings are linked by diphenyldiacetylene units has been reported revealing a system of interlocked dimers of trimers. The quinuclidine adduct formed a discrete trimer ;the different structure of the pyridine adduct was ascribed to pyridine n interactions with the pyrrole rings.6 Unsymmetrical porphyrin dimers and trimers have been prepared by intramolecular coupling of alkyne ~ubstituents.~ Such compounds are of interest as models for zinc enzymes. A phthalocyanine-pyrazinoporphyrazinederivative of zinc has been syn- thesized and found to be similar to homonuclear analogues but did not exhibit fluorescence.8 Dendritic zinc porphyrins have been prepared as models for electron- transfer proteinsg and a zinc porphyrin linked through a tetramethylene chain to a redox active crown ether has been prepared as a biomimetic model for a photosynthetic reaction centre.' * Redox potentials and fluorescence spectra have been determined for a series of zinc porphyrin-quinone cyclophanes in order to investigate the driving force for photo- induced electron-transfer reactions.X-Ray diffraction data indicated that an interac- tion between the quinone carbonyl group and the zinc centre could be considered as an alternative to through space electron-transfer in very fast solvent independent electron-transfer.' ' A time-resolved EPR study of the intermolecular interactions in the triplet dimers of zinc complexes of crown ether-substituted porphyrins and phthalocyanines showed that the metal played an important role in the former but not in the latter.I2 It was found that 2,3-dichloro-5,6-dicyano-p-benzoquinone oxidized zinc tetraneopentoxyphthalocyanineby one electron to the radical cation which was stable only in the solid state.A redox series of species were proposed on the basis of spectroscopic e~idence.'~ Photochemical formation and optical studies of the ring reduced anions [Zn(pc(-3))] -have been described and the electronic configuration of the anion radical defined using optical data and MCD. The first complete assignment of the optical spectrum for a porphyrin or phthalocyanine radical anion has been proposed.l4 H. L. Anderson A.Bashall K. Henrick M. McPartlin and J. K. M. Sanders Angew. Chem. Int. Ed. Engl. 1994 33 429. ' A. Vidal-Ferran C. M. Muller and J. K. M. Sanders J. Chem. SOC.,Chem. Commun. 1994 2657. ' N. Kobayashi Y. Higashi and T. Osa J. Chem. Soc. Chem. Commun. 1994 1785. P. J. Dandliker,F. Diederich M. Gross C. B. Knobler A. Louati and E. M. Sanford,Angew. Chem. Int. Ed. Engl. 1994 33 1739. lo L. Sun J. von Gersdorff D. Niethammer P. Tian and H. Kurreck Angew. Chem. Int. Ed. Engl. 1994,33 2318. H. A. Staab T. Carell and A. Dohling Chem. Ber. 1994,127,223;H. A. Staab C. Krieger C. Anders and A. Ruckemann Chem. Ber. 1994 127 231. l2 R. Miyamoto S. Yamauchi N. Kobayashi T. Osa Y. Ohba and M. Iwaizumi Coord. Chem. Rev. 1994 132 57. l3 Y. Fu G. Fu and A.B.P.Lever Inorg. Chem. 1994 33 1038. l4 J. Mack and M. J. Stillman J. Am. Chem. SOC.,1994 116 1292. Zinc Cadmium and Mercury 117 A new time-resolved Raman spectroscopic technique has allowed observation of the excited electronic states of Zn(oep) and confirmed theoretical predictions that Jahn-Teller distortion is much more pronounced in the triplet state than in the singlet state.lS Long-lived triplet excited states have been achieved by compartmentalizing Zn(tpp) in either an amphiphilic copolymer' or a liquid crystalline polymethacrylate bearing a cholesterol ~ide-chain.'~ Spectroscopic and theoretical studies on zinc(I1) octa-p-halotetrakis(pentafluoropheny1)porphyrins have pointed to substituent-in-duced saddling of the porphyrin. The observed stabilization of the HOMO was thought to be important in the design of porphyrin catalysts resistant to oxidative degradation." Electrochemical spectroscopic and MO investigations of zinc complexes of a tetraazaporphyrin containing two naphthalene molecules at opposite pyrrole rings have been reported and comparisons made with analogous phthalocyanines.A diporphyrin complex of zinc with N and N,S cores has been synthesized with the metal in the N ring. Only weak interaction was observed between the sub-units but with copper in the N,S ring there was strong interaction.20 Zinc porphyrin polymers in which rings are linked by acetylene units have been prepared as potential third-order non-linear optical materiak2' A tetra(3,5-di-t-butyl-pheny1)porphyrin zinc complex with 3',5'-di-t-butyl-2-stilbazole was found to be re-versibly photoswitchable by UV and visible light via trans-cis isomerization of the stilbazole.22 The use of Zn(tpp) in a photovoltaic cell has been reported.23 Zinc phthalocyanine complexes with three crown ethers and one hexanoyloxy acid side- chain have been prepared for the functionalization of polymeric chains or metal oxide surfaces.The new materials have potential for the determination of alkali and alkaline earth metals.24 A zinc porphyrin which formed a discotic mesophase has been extended via substitution of the porphyrin at the 5 and 15 positions to give calmitic nematic and smectic A phases at high temperatures2 A novel chiral metalloporphyrin complex which enantioselectively recognizes amino acids in the carboxylate forms has been synthesized.26A new synthesis of dinuclear porphyrin complexes with H-Zn Zn-Zn and Zn-Co centres which are of interest as electrocatalysts has been rep~rted.'~ A study of the solution conformation of Zn(hexaethyltetramethy1)porphyrinsugges-ted that the two species observed at low temperature by NMR correspond to cis- and trans-methyl groups of the meso ethyl groups rather than the syn- and anti-structures proposed earlier.28 A series of zinc derivatives of 2-nitro-substituted 5,10,15,20- tetraaryl porphyrins have been synthesized and investigated by spectroscopic and electrochemical technique^.^^ The polymeric structure of the sterically strained Is D.H.Kreszowski G. Deinum and G.T. Babcock J.Am. Chem. Soc. 1994 116 7463. Y. Morishima K. Saegusa and M. Kamachi Chem. Lett. 1994 583. " Y. Morishima S. Yusa K. Saegusa K. Tashiro and M. Kamachi Chem. Lett. 1994 631. T. Takeuchi H. B. Gray and W. A. Goddard 111 J. Am. Chem. Soc. 1994 116 9730. N. Kobayashi T. Ashida T. Osa and H. Konami Inorg. Chem. 1994 33 1735. R. P. Pandian and T. K. Chandrashekar Inorg. Chem. 1994 33 3317. '' H. L. Anderson S.J. Martin and D. D. C. Bradley Angew. Chem. Int. Ed. Enyl. 1994 33 655. 22 Y. Iseki and S. Inoue J. Chem. Soc. Chem. Commun. 1994 2577. 23 K. Takahashi K. Hashimoto T. Komura and K. Murata Chem. Lett. 1994 269. 24 J. Vacus G. Memetzidis P. Doppelt and J. Simon J. Chem. Soc. Chem. Commun. 1994 697. 25 D.W. Bruce M.A. Wali and Q.M. Wang J. Chem. Soc. Chem.Commun. 1994 2089. L6 K. Konishi K. Yahara H. Toshishige T. Aida and S. Inoue J. Am. Chem. Soc. 1994 116 1337. 27 X. Zhou and K. S. Chan J. Chem. Soc. Chem. Commun. 1994 2493. '' C.J. Medforth M. 0.Senge T. P. Forsyth J. D. Hobbs J. A. Shelnutt and K. M. Smith Inorg. Chem. 1994 33 3865. 29 T.A. Rao and B.G. Maiya Polyhedron 1994 13 1863. 118 I. B. Gorrell non-planar zinc octaethyltetranitroporphyrin has been shown to be achieved by utilization of the nitro groups for axial ligation to the zinc centre.,' A zinc phthalocyanine containing dienophile substituents has been rep~rted.~' The elec- trochemical properties of zinc phlorin anions have been found to depend on the nature of the axial ligand., Other Nitrogen-donor Ligands. The pyrimidine rings were found to bind in a monodentate fashion in the bis adduct formed in the reaction of ZnC1 with 5,7-dimethyl[ 1,2,4]triazolo[ 1,5-a]~yrimidine.~ The synthesis and structure of the racemic compound [Zn(tren)C1]C1.3H20 containing trigonal bipyramidal zinc has been reported.34 The reaction of [Zn(tppyz)(H,O),](C10,) with ZnC1 in EtOH/H,O gave [Zn5C1,,(tppyz)(H,0),], the structure of which showed two twisted dinuclear units connected by three Cl-Zn-Cl bridges.35 The complexes [(Fe,(CO),Cp,),(CN(CH,),NC)] (n = 2,3) have been shown to act as bidentate chelating ligands through nitrogen towards ZnX (X = C1 I OAc) CdX (X = C1 I) and HgC1,.36 N-R-substituted (R = H Me Bz) tris(benzimidazolylmethy1)amine (L) ligands have been used in the preparation of trigonal bipyramidal zinc complexes with various co-ligands (OH, C1 Br I ONO,) in the open axial position.In the aquo complexes OH could be replaced by F C1 Br CN N, OAc and tosylate. The crystal structures of [L.ZnCI][py.ZnCl,] and [L.ZnONO,][NO,] have revealed a coordina- tion geometry intermediate between tetrahedral and trigonal bipyramidal. The above ligands also formed complexes with biologically active ligands and the aquo complexes formed hydrogen bonds to nitriles and aldehyde^.,^ The reaction of ZnS0,.7H20 with 2,2' bipyrimidine gave [Zn,(p-C,H,N,)(H,O),] [S04],.2H,0. The structure of the cation is shown in (2)., 1+ The complexes [zn,(bipy)6(Co,)(H,o)2][C10,],(bipy).2H,0 in which the p3 carbonate bridged all three zinc atoms,,' [Zn(Him),(0A~),],~' and 30 M.O.Senge and K. M. Smith J. Chem. Soc. Chem. Commun. 1994,923. 31 C. Feucht T. Linssen and M. Hanack Chem. Ber. 1994 127 113. 32 G. Balducci G. Chottard C. Gueutin D. Lexa and J.-M. Saveant Inory. Chem. 1994 33 1972. 33 J. M. Salas M.A. Romero A. Rahmani and R. Faure Acta Crystallogr. Sect. C 1994 50 510. 34 A. Marzotto D.A. Clemente and G. Valle Acta Crystallogr. Sect. C 1994 50 1451. 35 M. Graf and H. Stoeckli-Evans Acta Crystallogr. Sect. C 1994 50 1461. 36 S. Schrolkamp W. Sperber D. Lentz and W. P. Fehlhammer Chem. Ber. 1994 127 621. 37 R. Gregorzik U. Hartmann and H. Vahrenkamp Chem. Ber. 1994,127,2117; U. Hartmann R. Gregorzik and H. Vahrenkamp Chem. Ber. 1994,127 2123. 38 G. de Munno and M. Julve Acta Crystallogr. Sect.C 1994 50 1034. 39 X.-M. Chen Q.-Y. Deng G. Wang and Y.-J. Xu Polyhedron 1994 13 3085. 40 X.-M. Chen Z.-T. Xu and X.-C. Huang J. Chem. Soc. Dalton Trans. 1994 2331. Zinc Cadmium and Mercury [Zn,(bipy),(OA~),][ClO~],~~ the first dinuclear zinc complex containing a monoden- tate carboxylate bridge have been prepared as models for the carboxylate-his- tidine-zinc interactions observed in zinc enzymes such as carbonic anhydrase. The structures of [Zn(phen),(OAc),][ClO,] and [Zn(bipy)(C5H5NCH,C0,][C10,] showed zinc to adopt a distorted octahedral geometry in the former and a distorted trigonal bipyramidal geometry in the latter.42 The structure of [Zn(bipy),(OAc)] [C1O,].2H2O was similar to the phen derivative., A mixture of zinc and sulfur boiled under reflux in pyridine gave py,Zn(S,) which contains a seven-membered ring with the zinc atom in a distorted tetra- hedral en~ironrnent.,~ The crystal structures of Zn(SCN),(hmta) and [Zn(SCN),.hmta.2H20] have been determined.In the former compound the zinc atom was tetrahedral and the hmta mondentate in the latter the zinc was octahedral and the ligand bridging bidentate. The polymer formed zigzag chains.45 A series of diorganozinc compounds R,Zn have been reacted with (2,6-Pr\C6H,),dab to give thermally unstable 1 1 complexes which subsequently under- went a regioselective alkyl or aryl group transfer from Zn to an imine nitrogen (R = Ph) or carbon atom (saturated R = But; unsaturated R Me Pr" Bun Bus CH,Bu' Bz) of the ligand (see Scheme 1).The alkylation was regioselectively directed by the introduction of bulky ortho aryl substituents on the nitrogen atoms. These results together with those obtained earlier for alkyl substituents were interpreted using both steric and electronic argument^.,^ Ar I RZn RZn c' - / .. Lr .. Ar Ar Ar Scheme 1 The mechanism of these reactions has been suggested to involve prior formation of R,Zn(R;dab) (R' = alkyl or aryl) followed by intramolecular ligand to ligand electron transfer (SET) generating via homolytic C-Zn bond cleavage a [RZn(R;dab)] '/R * radical pair. Collapse of this pair would give the observed products. An alternative 41 X.-M. Chen Y.-X. Tong and T.C. W. Mak Inorg. Chem. 1994 33 4586. 42 X.-M. Chen Z.-T. Xu X.-L. Yu and T.C.W. Mak Polyhedron 1994 13 2079. 43 X.-M. Chen Z.-T. Xu and T.C. W. Mak Polyhedron 1994 13 3329. 44 H. Li S. Du and X. Wu Acta Crystallogr. Sect. C 1994 50 498. 45 J. Pickardt G.-T. Gong S. Wischnack and C. Steinkopff 2. Naturforsch. Teil B 1994 49 325. 46 E. Wising K. van Gorp J. Boersma and G. van Koten Inorg. Chim. Acta 1994 220 55. 120 I. B. Gorrell mechanism involving cationic species has been discussed and the model species [RZn(Bu:dab)]OTf (R = Me 2,6 xylyl) and [Me,Zn(bipy)] were prepared. The radicals [RZn(Buidab)] have been prepared by independent routes and found to be in equilibrium with the C-C coupled species in which form they crystallized. Their reactivity with alkyl halides was described. The products of the thermal and photochemical decomposition of [R,Zn(Bu\dab)] have been in~estigated.~~ Triplet ligand-centred biradicals [Zn(Bu:dab),] could be prepared from activated zinc ZnH, Zn/ZnH, or ZnCI at -100“C.Room temperature EPR spectra revealed an equilibrium with the radical salt [Zn(Bu\dab),][Zn(Bu\dab),] .48 The thermal- and light-induced spin transition in [Fe,Zn -,(mtz),][ClO,] has been studied by Mossbauer spectroscopy and magnetic susceptibility measurements. The presence of zinc shifted the transition to lower temperature^.,^ A series of polymetallic complexes shown in (3) (X = C I) and (4) (for M =Zn X = C1 L =4-Mepy Bu‘NC; base-free Zn X = Et W(CO),Cp Mn(NC)(CO),Cp‘; for M = Cd X = Mo(CO),Cp W(CO),Cp Mn(NC)(CO),Cp’; for M = Hg W(CO),Cp) have been ~repared.~’ PhZY (CO),Fe-kL I ‘x Si(OMe) (3) (4) Reaction of PrlZn with pyz tetramethylpyrazine or 4,4’-bipy gave bis adducts characterized by intense ligand-ligand charge-transfer transition^.^ An X-ray analy- sis of the structure of [Zn(NSF,),][AsF,] has been reported.52 Oxygen-donor Ligands.-The crystal structure of zinc(1r) bis(phosphog1ycolate) dihyd- rate has been shown to consist of a linear polymer containing octahedral zinc atoms.’ Hydrogen bonding gave rise to a distorted tetrahedral environment around zinc in [Zn(C,C1,0,),(CH4N,S),].H,0,54[Zn(C,H502)2(CH,N,S)2],55 and [Zn(4-ClC7H402)2(tn)2].s6 EXAFS and vibrational spectra of acetone solutions of zinc ethylxanthate showed monodentate coordination for the latter with two acetone 47 E.Wissing M.Kaupp J.Boersma A. L. Spek and G. van Koten Organometallics 1994 13 2349; E. Wissing S. van der Linden E. Rijnberg J. Boersma W. J. J. Smeets A. L. Spek and G. van Koten Organometallics,1994,13,2602;E. Wissing E. Rijnberg P. A. van der Schaaf K. van Gorp J. Boersma and G. van Koten Organometallics 1994 13 2609. 4x M.G. Gardiner G. R. Hanson M. J. Henderson F.C. Lee and C. L. Raston Inorg. Chem. 1994,33,2456. 49 T. Buchen P. Poganiuch and P. Giitlich J. Chem. Soc. Dalton Trans. 1994 2285. 5o P. Braunstein M. Knorr M. Strampfer A. DeCian and J. Fischer J. Chem. Soc.,Dalton Trans. 1994,117. ” S. Hasenzahl W. Kaim and T. Stahl Inorg. Chim. Acta 1994 225. 23. 52 U. Rehrens R. Hoppenheit W. Isenberg E. Lork J. Petersen and R. Mews 2.Naturforsch. Teil B 1994 49 238.” T. Lis Acta Crystallogr. Sect. C 1994 50 181. 54 I. Potocnak M. Dunaj-Jurco U. Petricek and J. Cerniik Acta Crystullogr. Sect. C 1994 SO 1902. s5 K. Smolander M. Ahlgren M. Melnik J. Skorsepa and K. Gyoryova Acta Crystallogr. Sect. C 1994,SO 1900. 56 M.R. Sundberg Acta Cheni. Scand. 1994 48 195. Zinc Cadmium and Mercury 121 molecules weakly bound to zinc.57 The compound R'C(CH20R2),0H (R' = Bu' R2 = Pr'; R' = Bu' R2 = Et; R' = CF, R2 = Pr') reacted with Zn[N(SiMe,),] to give the monomeric dialkoxides which sublimed at low temperatures5 The first zinc-semiquinone structure has been determined for (tmeda)Zn(3,6-dbsq) . The compound has a diamagnetic singlet ground state and gives an EPR spectrum arising from an S = 1 excited state.59 The reaction of dmao with zinc halides gave ZnX,(dmao) in a 1:1 ratio or (ZnCl,),(damao) and ZnX,(dmao) (X = Br I) at higher ligand :zinc ratios.X-Ray structural analyses of ZnBr,(dmao) and ZnI,(dmao) and the solution behaviour of the compounds were reported.60 The zincates M,[Zn(OCMe,),] (M = Na K) have been prepared from MOCMe and ZnCl,. Both compounds sublimed at low temperature and are hydrocarbon soluble.61 Molecular solid solutions of the CrfZn Tutton salts (NH,)2[Cro~,Zno~,(H2~)6](so4)2 and (NH,)2[Cro~22Zno~7,(H20)4](S0,)2 have been studied using single crystal X-ray analysis and neutron diffraction. The results show6 that the aqua ligands in the latter compound are disordered. The compound Zn( 1 ,2-C2BlOH ,C02),.2THF has been synthesized from the carboxylic acid and Et,Zn.63 Incorporation of divalent zinc into the structure of AlPO,-18 yields solid acid catalysts that generate 65-70% ethene and propene with 100°/~ conversion of methanol in the range 35M00"C.64 Sulfur-and Selenium-donor Ligands.-Solid state NMR spectra of [M(Se,),I2 -(M = Zn Cd Hg) have been reported as well as the crystal structure of [(Me,N),]- [Hg(Se,),].O.SDMF and the FT Raman spectrum of [(Me,N),][Cd(Se,),].65 The reaction of Zn[N(SiMe,),] with 2,6-di-mes-C,H,SH has been shown to give a monomeric two-coordinate zinc complex with a low S-Zn-S angle of 151.7"C probably as a result of metal-ring interactions.66 Insertion of sulfur into half the metal-carbon bonds of Et,Zn yielded [Zn(SEt)Et] which exhibited a new molecular structure based on edge-shared MS tetrahedra.67 Compounds of general formula M'M2(EPh),L [M' = Zn Cd Hg; M2 = divalent (x = 4)or trivalent (x = 5) rare earth; E = S Se Te; L = thf py] have been prepared as potential precursors to ternary chalcogenides.Crystal structures of a europium(I1) and a samarium(rI1) complex were reported.68 Octanuclear sulfur bridged complexes [{Ir(aet),),M,O]Br, M = Zn or Zn,.,Co,., with a tetrahedral M core have been synthe~ized.~~ Monomeric five- coordinate bis(diethyldithiocarbamato)M(trialkylphosphine)complexes (M = Zn Cd; alkyl = Me Et) have been synthesized by addition of trialkylphosphines to toluene solutions of bis(diethy1dithiocarbamato)M.The compounds are monomeric in the solid state and the phosphines are labile in solution.The depe bridged dinuclear 57 M. Valli P. Persson and I. Persson Acta Chem. Scand. 1994 48 810. 58 W.A. Herrmann and N. W. Huber Chem. Ber. 1994 127 821. 59 C. W. Lange B.J. Conklin and C.G. Pierpont Inorg. Chem. 1994 33 1276. 6o G. Borisov S. G. Varbanov L. M. Venanzi A. Albinati and F. Demartin Inorg. Chem. 1994 33 5430. 61 A. P. Purdy and C. F. George Polyhedron 1994 13 709. 62 F.A. Cotton L. M. Daniels L. R. Falvello C.A. Murillo and A. J. Schult Inorg. Chem. 1994 33 5396. 0.Kriz A. L. Rheingold M. Shang and T. P. Fehlner Inorg. Chem. 1994 33 3777. 64 J. Chen and J.M. Thomas J. Chem. Soc. Chem. Commun. 1994 603. 65 P. J. Barrie R. J. H. Clark R. Withnall D.-Y. Chung K.-W. Kim and M.G. Kanatzidis Inorg. Chem. 1994,33 1212. 6b J.J.Ellison and P. P. Power Inorg. Chem. 1994 33 4231. '' D. Zeng M. J. Hampden-Smith and E.N. Duesler Inorg. Chem. 1994 33 5376. M. Berardini T. Emge and J.G. Brennan J. Am. Chem. Soc. 1994 116 6941. 69 K.-I. Okamoto T. Konno and J. Hidaka J. Chem. SOC.,Dalton Trans. 1994 533. 122 I. B. Gorrell complexes [(Et,NCS),M1(depe)M2(SCNEt,),] (MI = M2 = Zn; M' = Zn; M2 = Cd) were also prepared. These compounds decomposed to give metal sulfides.70 A distorted trigonal bipyramidal environment was found for zinc in the structure of (Et,NCS,),Zn(depe)Zn(S2CNEt2)2.71 Reactions of [Zn(EAr),] (E = S Se; Ar = 2,4,6-BU\C6H2) with N S or P donor ligands gave monomeric three-coordinate complexes Zn(EAr),(L) (L = 2,6-lutidine tht PMe, PMePh,). With excess N-methylimidazole tetracoordinate complexes were obtained which lost one imidazole on recrystallization from toluene.The results illustrated that Zn-L bond lengths even with a high degree of steric hindrance are determined by electronic factors.72 Halogen-donor Ligands.-The complexes formed between ZnC1 and aromatic al- dehydes were found to exhibit three different structural types.73 Solution equilibria between zinc@) and halide ions have been studied in DMA. Formation-constants -enthalpies and -entropies of these tetrahedral binary and ternary species have been determined.74 The reaction of the clusters Mo,S,L (L = R,P(S)S; R = Et Pr) with MI (M = Zn Cd Hg) in the presence of pyridine gave [Mo,S,L,py,][MI,py] (M = Zn Cd) and [MO,S,L~~~,][H~I~].~~ The preparation of the zinc chloride complex with the new sterically-hindered thiourea (5) has been reported.76 S Me,NAN,CH2CH =CH2 @NCHjMe2 L/ A series of complexes of dmpo (6) ZnX,(dmpo) (X = C1 Br I NO,) has been synthe~ized.~~ The complex ZnCl,(Me,SiNPMe,) has been prepared as a monomer with a distorted tetrahedral zinc centre.78 Complexes of 4-nitrosodimethylaniline with ZnC1 (1:2) CdC1 (1 l),CdI,(1 :2) and HgI (1 :2) have been prepared and studied using solid state NMR.79 The structures and binding energies of (MX,) (M = Zn Cd; X = F C1 H) have been computed at the ab initio level.All except Cd,H, show symmetrically bridged D, structures in contrast to those expected on the basis of quasi-relativistic calculations for (HgHal,) . Relativistic effects were found to change trends in dimerization energy from Hg > Cd > Zn to Cd > Zn >> Hg and the trends in Group 12 chemistry involving electronegative ligands could be understood in terms of electrostatic bonding and its relativistic reduction for mercury.80 Reaction of MCGaH,] (M = Li Na) with ZnCl,(pmdeta) gave the heterobimetallic species 70 D.Zeng M. J. Hampden-Smith T. M. Alam and A. L. Rheingold Polyhedron 1994 13 2715. 71 D. Zeng M. J. Hampden-Smith and E. M. Larson Acta Crystallogr. Sect. C 1994 50 1OOO. 72 M. Bochmann G.C. Bwembya R. Grinter A. K. Powell K. J. Webb M. B. Hursthouse K. M. A. Malik and M. A. Mazid Inorg. Chem. 1994 33 2290. 73 B. Muller M. Ruf and H. Vahrenkamp Angew. Chem. Int. Ed. Engl. 1994 33 2089. 74 H.Suzuki M. Koide and S. Ishiguro Bull. Chem. Soc. Jpn. 1994,67 1320. 75 H. Diller H. Keck W. Kuchen and H. Wunderlich Inorg. Chim. Acta 1994 216 177. 76 D.J. Williams T. A. Ly J. W. Mudge D. VanDerveer and R. L. Jones Inorg. Chim. Acta 1994,218 133. 77 S. Varbanov E. Russeva and A. Ganchev Z. Naturforsch. Teil €3 1994 49 258. 78 R. M. zu Kocker G. Frenzen B. Neumuller K. Dehnicke and J. Magull 2.Anorg. Allg. Chem. 1994,620 431. 79 M. Cameron B. G. Gowenlock and G. Vasapollo Polyhedron 1994 13 1371. 8o M. Kaupp and H.G. von Schnering Inorg. Chem. 1994 33,4718. Zinc Cadmium and Mercury 123 Zn(q’-GaH,)Cl(pmdeta) whereas reaction of MCGaH,] with ZnCl,(tmeda) gave Zn(q2-GaH,)Cl(tmeda); MCBH,] gave the analogous borohydride.81 3 Cadmium Carbon-donor Ligands.-The multidimensional structures associated with poly-cyanocadmium compounds continue to excite interest showing similarity to silica frameworks and often forming clathrates.The structure of [Cd(CN),.2/3hmta] has been reported.82 The compounds Cd(CN),.pyz and Cd(CN),.{ 1,4-bis(4-pyridyl)butadiyne}have been shown to contain square-grid [Cd(CN),] sheets linked by pyz or bis(pyridy1butadiyne) bridges. The latter initially colourless complex acquired a deep blue colour on exposure to light indicating diacetylene polymerization in the crystal.83 The reaction of CdC1 with K[Ag(CN),] and 4,4‘-bipy gave [Cd(4,4’-bipy),fAg(CN),},]and the reaction of K,[Cd(CN),] AgNO, and pyrazine gave [Cd(pyz)(Ag,(CN),}(Ag(CN),}]. The former complex consisted of two- and the latter of three-separate interpenetrating frameworks built up of 2D networks supported by 4,4’-bipy or NC-Ag-CN pillars re~pectively.~, Enantiomorphic crystals of Rb[Cd(Ag(CN),),] have also been found to contain three identical independent interpenetrating framework^.^^ The cadmium atom in [Cd(bipy)][Ni(CN),] was found in a highly distorted octahedral environment with the [Ni(CN),] units bridging four cadmium atoms to form an infinite 2D network.The bipy units chelated cadmium alternately above and below the chains.86 An aqueous solution of CdCl, K[Ag(CN),] and 4-Mepy gave the clathrate [Cd(4-Mepy),{Ag(CN),},](4-Mepy),a double interwoven network and CCd(4-Mepy),(Ag (CN),}][Ag(CN),] made up of infinite linear chains8 Absorption of acetonitrile vapour by an aqueous solution containing CuCN and K,[Cd(CN),] gave [Cd(H,O),Cu(CN),].MeCN a layered clathrate structure consisting of [Cu,(CN),] 4-units with each nitrogen linked to a cadmium.88 Two new [Cd(CN),] frameworks with linear channels of hexagonal cross-section have been found in Cd(CN),-G (G = DMF or DMSO) clathrate~.~~ The cadmium cyanide host clathrates Cd8(CN),,(H,0),.6G (G = Et,O PrlO) and Cd,(CN),(H2O),.2Pr~O have been prepared and structurally characterized.” A series of 17 inclusion compounds of composition [am.xG][Cd,(CN),] (am = organo-nitrogen or -sulfur cation; x = 1-2) including six structural types have been obtained from the 3D anionic [Cd,(CN),]- salt of a cation am and a neutral guest molecule G.9’ Three series of clathrate compounds Cd(CN),.G [CdM(CN),].2G (M = Zn Hg) and [NMe,.G] [CuM(CN),] (M = Zn Cd) have been ~ynthesized.~ 81 G.A.Koutsantonis F.C. Lee and C. L. Raston J. Chem. Soc. Chem. Commun. 1994 1975. J. Pickardt and G.-T. Gong Z. Anorg. Allg. Chem. 1994,620 183. 83 B.F. Abrahams M. J. Hardie B. F. Hoskins R. Robson and E. E. Sunderland J. Chem. SOC. Chem. Commun. 1994 1049. 84 T. Soma H. Yuge and T. Iwamoto Angew. Chem. Int. Ed. Engl. 1994,33 1665. 85 B.F. Hoskins R. Robson and N.V.Y. Scarlett J. Chem. SOC. Chem. Commun. 1994 2025. 86 M. Hashimoto and T. Iwamoto Acta Crystallogr. Sect. C 1994 50 496. ” T. Soma and T. Iwamoto Chem. Lett. 1994 821. 88 S.-I. Nishikiori and T. Iwamoto Chem. Lett. 1994 1199. H9 J. Kim D. Whang Y.-S. Koh and K. Kim J.Chem. Soc. Chem. Commun. 1994,637. 90 T. Kitazawa T. Kikuyama M. Takahashi and M. Takeda J. Chem. Soc. Dalton Trans. 1994 2933. 91 T. Kitazawa S.-I. Nishikiori and T. Iwamoto J. Chem. Soc. Dalton Trans. 1994 3695. 92 T. Kitazawa S.-I. Nishikiori R. Kuroda and T. Iwamoto J. Chem. SOC.,Dalton Trans. 1994 1029. 124 I. B. Gorrell Nitrogen- and Phosphorus-donor Ligands.-A halide free route has been used to synthesize the new complexes [Cd (PhC-C) (tmeda)] and [Li (thf),] [Cd(C ,H8N),] from Cd[N(SiMe,),],.93 { [Cd(4,4'-bipy),]N03],) has been found to consist of 2D networks made up of layers of edge-sharing planar squares with a cadmium at each corner and a 4,4'-bipy at each side. The compound formed a 1:2 clathrate with o-dibromobenzene and catalysed the cyanosilylation of aldehyde^.^ The preparation and structure of a 1Dpolymer {[Cd,(p-bpe),](NO,),), containing seven-coordinate cadmium has been reported.95 The disilylphosphido complexes M[P(SiPh,),] (M = Zn Cd Hg) have been prepared and found to be monmeric in solution.A crystal structure determination of the cadmium complex revealed a two-coordinate linear geometry and the compound formed unstable adducts with pyridine and PMe,.96 Oxygen-donor Ligands.-Infrared studies have shown that dimethyl and diethyl cadmium react with both hydroxyl and siloxane groups on a silica surface to form -=Si-0-Cd-CE and GS1-H fragments. At 200 "C p-elimination yielded GSi-0-Cd-H and at 600 "Cmetallic cadmium and regeneration of Depending on the amount of Hmoe used the partial alcoholysis of [cd(C6F5),] gave the complexes [Cd4(C6F5)4(moe)41 [Cd7(C6F5)fj(moe)81 and [Cdf5(C6F5)4(moe)fj] which have (C~&L~-OR)~)~+, (Cd7(p3-OR)8)6+ and (Cd6(p3-OR)8)4+ cores re~pectively.~~ The synthesis and X-ray structural analysis of polymeric [Cd(OH)(H,L)(H,O),],.nH,O (H,L = piperazine-1,4-diylbis(methylene)bis(phosphonic acid) have been re- ported.99 The volatile alkoxide Cd[OC(OCH,Pr'),Bu'] made from Cd[N(SiMe,),] and the alcohol has been found to be dimeric in the solid state but monomeric in the gas-phase.' O0 The preparation and spectroscopic characterization of [MeO(CH,),] Cd has been reported.'" Sulfur- and Selenium-donor Ligands.-The compound obtained by boiling CdBr, CS, NaOEt and 4-methoxyaniline under reflux in ethanol was found to be a dimer of distorted octahedral cadmium atoms each coordinated to six sulfur atoms from one bidentate xanthato group two bridging bidentate xanthato groups and one monodentate N N'-bis(4-methoxyphenyl)thiourea.' O2 The crystal structure of [Cd(S,PPh,),] shows a dimer containing an eight-membered ring each cadmium atom also being bonded in a bidentate fashion to an external S,PPh ring.lo3 A number of cadmium thiocyanate complexes have been investigated using '',Cd NMR to characterize the various modes of linkage isomerism exhibited by the SCN y3 D.Barr A.J. Edwards P. R. Raithby M.-A. Rennie K. Verhorevoort and D. S. Wright J. Chem. Soc. Chem. Commun. 1994 1627. y4 M. Fujita Y.J. Kwon S. Washizu and K. Ogura J. Am. Chem. Soc.1994 116 1151. 95 M. Fujita Y. J. Kwon M. Miyazawa and K. Ogura J. Chem. Soc. Chem. Commun. 1994 1977. 96 M.A. Matchett M.Y. Chiang and W. E. Buhro Inorg. Chem. 1994 33 1109. 97 V. A. Dodonov A. A. OIeynik M. 3.Molotovshchikova G. N. Lysenko. and 0.N. Druzhov Russ. Chem. BuEl. 1993 42 1639. 98 1. Biisching and H. Strasdeit .I. Chem. Soc. Chem. Commun. 1994 2789. 99 N. Choi I. Khan R.W. Matthews M. McPartlin and B. P. Murphy Polyhedron 1994 13 847. lo" W.A. Herrmann N. W. Huber and T. Priermeier Angew. Chem. Int. Ed. EngI. 1994 33 105. lo' M. J. Almond M. P. Beer P. Heath C. A. Heyburn D. A. Rice and L. A. Sheridan J. Organomet. Chem. 1994 469 11. lo2 Z.-F. Sun C.-Y. Duan X.-Z. You and X.-Y. Huang Acta Crystallogr. Sect. C 1994 50 1012. J. S. Casas M.S. Garcia-Tasende A. Sanchez J. Sordo E. M. Vazquez-Lopez E. E. Castellano and J. Zukerman-Schpector Inorg. Chim. Acta 1994 219 115. Zinc Cadmium and Mercury groups.' O4 Plasma desorption time-of-flight mass spectrometry has been used to investigate cadmium arenethiolates. Gas-phase clustering has been observed and a structural model involving Cd,(SR) rhombuses sharing trans edges was presented to account for the compositions and transformations of the ions."' A series of pentafluorophenyl cadmium thiolates [{Cd(C,F,)(SR)},] (n = 4 co;R = Bu' 2,4,6- Pr\C,H, 2,4,6-Bu\C6H,) have been prepared.lo6 The compound [HNEt,],[Cd,(p- SC6H,Bu'-4),(SC,H,Bu'-4)~~~] consisted of a Cd,(p-S) adamantane-like cage.lo7 Cadmium chalcogenide complexes attract attention as potential CVD precursors to the Group 2-6 semiconductors CdS quantum dots and photocatalysts.Thus the synthesis and characterization of NpCdE,CNEt (E = S Se) and NpZno,,Cdo~,- Se,CNEt have been reported and have included the X-ray structural analysis of dimeric NpCdSe,CNEt,. All compounds decomposed on heating to give the binary or ternary chalcogenide. lo* The thermal decomposition of CdX2.2SC(NH,) (X = C1 Br Illo9 or Cd(RCO,),.nSC(NH,) (R = H n = 2; R = Me II = 1-2)'1° has been shown to give CdS. Pyridine selenolate complexes of cadmium(i1) and mercury(I1) have been prepared and characterized. The cadmium compound was polymeric but the mercury compound was square planar with only weak intermolecular interactions. Both sublimed without decomposition and decompose at higher temperatures to yield MSe.Negatively charged stabilizers such as polyacrylic acid formed microcrystal- line CdS photocatalysts which on photoreduction of CO gave only formate whereas positively charged stabilizers such as polyethyleneimine gave only CO.' l2 CdS microcrystals covalently bound with viologen groups have been prepared and found to mediate electron-transfer to methylene blue in solution. Monodisperse colloidal silica-CdS nanocomposites have been prepared using water-in-oil microemulsions to produce colloidal silica which was then exposed to Cd(NO,) and (NH,),S."4 Halogen-donor Ligands.-The cadmium atoms in [Et,N],[CdBr,] have been shown to be tetrahedral.' lS The reaction of CdBr with 3-methyl-4-nitropyridine-N-oxide gave [Cd(C,H,N,O,),Br,] the structure of which showed octahedrally coordinated cadmium (20,4Br) with 1D chains formed by edge-sharing through bromine.' l6 The structure of cadmium tetrahydroborate in thf was found to be fluxional and best described as Cd[(p-H),BH,],.nthf.Reaction with Li[BH,] gave Li[Cd(BH,),] while Li [Cd(BH,),] .4 diglyme precipitated from diglyme solutions. Equilibria involving ICd(BH,) CdI, CdI; [Cd(BH,),] -,and/or [ICd(BH,),] -resulted from Cd(BH,) and LiI in thf or diglyme.' l7 '" K. Eichele and R. E. Wasylishen lnory. Chem. 1994 33 2766. lo' A.G. Craig K. J. Fisher R. Garbutt I.G. Dance and P.J. Derrick lnorg. Chem. 1994 33 2890. lo6 A,-K. Duhme and H. Strasdeit Z. Naturforsch. Teil B,1994 49 119. lo' K. Tang T. Xia X.Jin and Y. Tang Polyhedron 1994 13 3023. I. Abrahams A. Malik M. Motevalli and P. O'Brien J. Organomet. Chem. 1994 465 73. '09 M. Stoev and S. Ruseva Monatsh. Chem. 1994 125 599. M. Stoev S. Ruseva and B. Keremidchieva Monatsh. Chem. 1994 125 1215. Y. Cheng T. J. Emge and J. G. Brennan lnorg. Chem. 1994,33 3711. H. Inoue R. Nakamura and H. Yoneyama Chem. Lett. 1994 1227. T. Torimoto K. Maeda T. Sakata H. Mori and H. Yoneyama Chcm. Lett. 1994 977. S.-Y. Chang L. Liu and S.A. Asher J. Am. Chem. Soc. 1994 116 6739. M. Geselle and H. Fuess Acta Crystullogr. Sect. C 1994 50 1582. 'I6 H. Sheng-Zhi S. Da-Shuang H. You-Qing L. Song-Xian and Y. Yan-Chao Acta Crystallogr. Sect. C 1994 50 893. H. Noth and M. Thomann Z. Naturforsch. Teil B 1994 49 9. 126 I.B.Gorrell 4 Mercury Carbon-donor Ligands.-The synthesis and spectroscopic characterization of [Hg(CO),][Sb,F J2 and [Hg,(CO),][Sb,F 'I2 the first thermally stable carbonyl derivatives of a post-transition element have been reported.' l8 The organomercuric hydrides and deuterides RHgH and RHgD have been characterized in solution by low temperature multinuclear NMR (R = alkyl cycloalkyl Ph)' ' and mass spectro- scopic and NMR (R = Me Et Ph C6F5) techniques.12' Electrospray mass spectra have been used to investigate ligand exchange reactions in solution for [MeHgL] + (L = nitrogen base). Reaction with other nitrogen bases phosphines phosphine sulfides and selenides were reported.',' A 2 1 adduct [Cr(NH,),NC],Hg6+ containing the Cr-NC-Hg link has been formed in aqueous solution by reaction of + Cr(NH,),CN2 with Hg2 + .Evidence was also obtained for 4:1and 2 1adducts in the solid state.', A series of bis(fluoropheny1)mercury compounds have been prepared by decar- boxylation of the corresponding fluorobenzoates in boiling pyridine.' 23 Secondary interactions cause angles at mercury to deviate from linearity in the structures of and (C1Hg),C(COMe),.MeCN.'25 (C1Hg),C(COMe)C0,Et.1/2MeCN124 (2-pyr-roly1)mercuric chloride has been prepared and used as a ligand transfer agent in the preparation of osmium and ruthenium derivatives.126 The compounds Hg(CHCl,) and RHgCHCl (R = Me Et) have been synthesized and ~haracterized.'~~ The reactions of [Bu,N],[cis-Pt(C,F,),(C=CR),] (R = But SiMe,) with HgX (X = C1 Br I) have given the monomeric bis y2-alkyne mercury(I1) compounds [Bu,N],[(~~s-P~(C~F,),O,)H~~~].Also [Bu4N],[PtCrCR),].2H2O have been shown to react with HgX in a 1:2 ratio to give the corresponding trinuclear products.12* Treatment of CpM(CO) (M = Mn Re) with 5 equivalents of Hg(OAc) gave the pentakis(acetoxy)mercuric derivatives in high yields. The manganese compound has been converted into pentahalogeno compounds by CuCl, CuBr, or K13.'29 The preparation of 1,2-bis(chloromercuri)alkenes,1-trimethylsilyl-2-chloro-mercurialkenes and 1-trimethylsil yl-2-organomercurialkenes by transmetallation of the corresponding trimethylstannyl compounds with HgC1 and RHgCl (R = Me Ph) have been reported.' 30 Kinetics of the acetoxymercuration of 1-arylpropynes have been investigated.' The mercuration of a series of aryliminomethylferrocenes occurred predominantly in an ortho position of the substituent ferrocenyl ring suggesting initial coordination of mercury to the imino nitrogen with subsequent electrophilic attack.An X-ray structural analysis revealed the Hg-N intramolecular 118 H. Willner M. Bodenbinder C. Wang and F. Aubke J. Chem. SOC. Chem. Commun. 1994 1189. 11' K. Kwetkat and W. Kitching J. Chem. SOC. Chem. Commun. 1994 345. ''* P. J. Craig H. Garraud S.H. Laurie D. Mennie and G. H. Stojak J. Organomet. Chem. 1994,468 7. ''' A. J. Canty and R. Colton Inorg. Chim. Acta 1994 215 179. ''' M. Rievaj D. Bustin J. Mocak P. Riccieri and E. Zinato Inorg. Chim. Acta 1994 216 113. N. J. Barassi G. B.Deacon and J.A. Weigold Z. Anorg. Allg. Chem. 1994 620 993. lZ4 P. Toledano C. Bonhomme M. Henry and J. Livage Acta Crystallogr. Sect. C 1994 50 365. lZ5 C. Bonhomme P. Toledano and J. Livage Acta Crystallogr. Sect. C 1994 50 1590. M. M. P. Ng W.R. Roper and L. J. Wright Organometallics 1994 13 2563. R. Imdahl H.-D. Hausen and J. Weidlein 2. Anorg. Allg. Chem. 1994 620 625. lZ8 J. R. Berenguer,J. Fornies E. Lalinde A. Martin and M.T. Moreno J. Chem. SOC.,Dalton Trans. 1994 3343. lZ9 S.A. Kur M.J. Heeg and C. H. Winter Organometallics 1994 13 1865. 130 T.N. Mitchell and B. Kowall J. Organomet. Chem. 1994,471 39. 13' B. Floris and E. Tassoni Organometallics 1994 13 4746. Zinc Cadmium and Mercury 127 intera~ti0n.l~~ A study of the mercuration of benzylideneanilines showed that the mercury was directed to the para position of the N-phenyl ring.', Mercuration of the liquid crystalline dialkylazobenzenes gave RHgCl (R = C6H,(N=NC,H,X-4')-2; X = C,H, C10H2' OC,H, OC8H17).However none of the compounds showed mesomorphic behaviour. '34 Mercurated phosphorus ylides Ph,P=CR[HgN(SiMe,),] (R = Me Et Pri Ph) have been prepared. Reaction with PhCHO gave the vinylmercury amides PhHC=CR[HgN(SiMe,),] which were cleaved by aqueous NaOH to give divinylmercury compounds (PhHC=CR),Hg. Stereochemistry and a salt effect were disc~ssed.'~ The first example of a dithiadiazolium ring bound to a metal centre via the carbon was reported with the preparation of [Hg(CNSNS),][AsF,],. Reaction with X (X = Br I) gave [XCNSNS][ASF,].'~~ Nitrogen-donor Ligands.-A study of the substitution of a homodinuclear mercury(I1) porphyrin with copper(1r) in aqueous solution using a new stopped-flow EXAFS technique has been reported and the reaction mechanism discussed.' 37 Crystals of Hg(SCN),.2HgC12.2hmta were obtained from aqueous solution.The structure consisted of a network of chains with hmta lying in channels between the chains as bridging ligands.' 38 Sulfur-donor Ligands.-The mercury atom in PhHg(S,OCEt) has been shown to be linear.', The compounds [RHg(S,PR;)] (R = Me Ph; R' = Et Cy) have been synthesized and characterized including an X-ray structural analysis of [HgPh(S,PEt,)] which showed the angle at mercury to be 177".140 A series of salts [A],[(p-SR),-,(p-X),(HgX),] (A = R,N Ph,P; R = Et Pr' Bun; X = C1 Br I; m = &2) have been prepared as models for the mercury binding site in metallo- thioneins and investigated using 19,Hg NMR and X-ray diffra~ti0n.l~~ The reaction of (Ph,P),PtSCH,COCH with HgX (X = C1 Br I) gave 1:1 dimeric adducts with distorted tetrahedral mercury centres.142 Halogen-donor Ligands.-A review of chloromercury(I1) anions has appeared.143 The kinetics of formation and photoredox chemistry of iodomercurate(I1) complexes in MeCN have been inve~tigated.',~ The structure and bonding in solvated (with H,O MeCN dmso py) mercury-dihalide and -dicyanide complexes have been studied using EXAFS and theoretical ~alculations.'~~ The adducts of an olefinic double betaine with 132 S.Q. Huo Y.J. Wu Y. Zhu and L. Yang J. Organornet. Chem. 1994 470 17. 133 P. Chattopadhyay and C. Sinha Polyhedron 1994 13 2689. 134 J. Vicente M. D. Bermudez F. J. Carrion and G. Martinez-Nicolas J. Organomet. Chem. 1994,480 103. 13' M. Steiner H. Pritzkow and H. Grutzmacher Chem. Ber. 1994 127 1177. A. J. Banister I. Lavender S. E. Lawrence J. M. Rawson and W. Clegg J. Chem. Sou.,Chem. Cornrnun. 1994 29. H. Ohtaki Y. Inada S. Funahashi M. Tabata K. Ozutsumi and K. Nakajima J. Chem. Sou. Chem. Commun. 1994 1023; M. Tabata and K. Ozutsumi Bull. Chem. Sou. Jpn. 1994,67 1608. 138 J. Pickardt G.-T. Gong and D. Roleke Z. Naturforsch. Teil B 1994 49 321. 139 E. R.T. Tiekink Acta Crystallogr. Sect. C 1994 50 861. I4O J. S. Casas A. Castiiieiras A. Sanchez J. Sordo and E.M. Vazquez-Lopez J. Organomet. Chem. 1994 468,1. i41 P.A. W. Dean J. J. Vittal and Y. Wu lnorg. Chem. 1994 33 2180. 142 W. Henderson B. K. Nicholson and R. D.W. Kemmitt J. Chem. SOC.,Dalton Trans. 1994 2489. 143 D.A. House W.T. Robinson and V. McKee Coord. Chem. Rev. 1994 135/136 533. 0.Horvath and A. Vogler Inorg. Chim. Acta 1994 221 79. 14' R. Akesson I. Persson M. Sandtrom and U. Wahlgren Inory. Chem. 1994 33 3715. 128 I. B. Gorrell HgX (X = C1 Br) have been prepared and structurally characterized as [{Hg,L2X,.6HgX,},] (L = (Me,NC,H,N),C,(CO,),). The structure contained a centrosymmetric 14-membered ring with nearly linear HgX units that were further interlinked by weak intermolecular contacts to form a polymeric network. A relativistic ab initio pseudopotential study of (HgX,) (X = F C1 Br 1 H) showed that the preference of many solid mercury compounds for molecular structures with low coordination number and lower boiling points (as compared with the correspond- ing zinc and cadmium compounds) is due to relativistic effects.In particular the relativistic increase of the Hg(6s) ionization energy reduced the charge separation in and intermolecular interactions between HgX molecules with electronegative sub~tituents.'~' Such calculations also showed that HgF should exist as a free molecule whereas CdF and ZnF would eliminate fluorine exothermically. A large relativistic destabilization of HgF was considered responsible. Possible preparative routes to HgF were disc~ssed.'~~ The stability of Hgf+ was found to be due to differential aggregation/solvation effects in the solid state modified by relativistic effects.The zinc and cadmium analogues as opposed to Hgf +,were considered most likely to be found in the gas-~hase.'~~ Mercury-Transition-metal Complexes.-The Cr-Hg-Cr unit in Hg[Cr(CO) C,H,(CO,Et)] was shown to be 1ir1ear.l~' The syntheses of [E(CO),($-RC,H,)] ,Hg (E = Cr Mo W; R = Me Et Bun) from PhHgCl and the corresponding lithium derivative have been described.' 51 The reaction of HgC1 with [Mo(CO),(dmp)] gave [Mo(CO),(dmp)(HgCl)Cl] a capped trigonal prism. The reaction of this and related derivatives with tin dihalides was studied.' 52 The preparation and structural characterization of the pentanuclear clusters [PPh,][Mn,(CO) ,(p3-H)(p-HgE)] (E = Mo(CO),Cp W(CO),Cp Mn(CO), Co(CO), Fe(CO),Cp C,Cl, 2,3,4,6-Cl,C& 2,4,6-C1,C6H,) from [PPh,][Mn,(CO),,(p-H)] and EHgCl have been reported.' 53 The compounds Re,(p-PR,)(CO),(HgE) and ReMo(pPR,)Cp(CO),(HgE) (R = Ph Cy; E = C1 W(CO),Cp) have been prepared and structurally characterized.' 54 The preparation of [M{SeFe3(C0)9),]2- (M = Cd Hg) has been reported.The mercury was tetrahedral and bridged the Fe-Fe bond in both iron units.', The reaction of [PPh,][Fe,(CO) with EHgCl (E = Mo(CO),Cp W(CO),Cp Mn(CO), Co(CO), Fe(CO),Cp) gave the pentametallic compounds [PPh,]- [Fe,(CO),,(p-CO)(p-HgE)] which showed a spiked butterfly geometry; electrochemi- cal oxidation gave [Fe,(CO) ,(p-HgE)] '.156 Mercury was inserted into the Fe-I bonds in [FeI,(CNR),] (R = But Ph 4-MeC,H4)in the presence of phosphines L to 146 D.-D.Wu and T.C. W. Mak Polyhedron 1994 13 3333. M. Kaupp and H. G. von Schnering Inorg. Chem. 1994 33 2555. 14* M. Kaupp M. Dolg H. Stoll and H.G. von Schnering Inorg. Chem. 1994 33 2122. 149 M. Kaupp and H.G. von Schnering Inorg. Chem. 1994 33,4179. L.-C. Song Q.-M. Hu R.-J. Wang and H.-G. Wang Acta Crystallogr. Sect. C 1994 50 1592. L.-C. Song Z.-F. Tao Q.-M. Hu R.-J. Wang and H.-G. Wang Polyhedron 1994 13 2179. lS2 M. Cano M. Panizo J. A. Campo E. Guitierrez-Puebla M. A. Monge and C. Ruiz-Valero Polyhedron. 1994 13 1669. 153 0.Rossell M. Seco G. SegalCs S. Alvarez M. A. Pellinghelli and A. Tiripicchio Organometallics 1994. 13 2205. 154 H.-J. Haupt A. Merla and U.Florke Z. Anorg. Allg. Chem. 1994 620 999. M. Shieh and Y.-C. Tsai Inorg. Chem. 1994 33 2303. R. Reina 0.Rossell M. Seco D. de Montauzon and R. Zquiak Organometallics 1994 13 4300. Zinc Cadmium and Mercury 129 give [Fe(HgI,)L(CNR),] (n = 4 L = PPh, dppm; n = 3 L = d~pe).'~~ The reaction of Hg(OAc) with Fe(CO) in ROH (R = Me Et) gave Hg[Fe(CO,R)(CO),] with linear (R = Me) or nearly linear coordination (R = Et) at mercury.158 Compound (7) reacted with Pt(C,H,)(PPh,) to give cis-and trans-[Fe(CO),{p-Si(OMe),(OMe))(p-dppm)(p-H g)(Pt(c,Cl,)PPh,)]. The reactivity of these species was investigated.' 59 Ph2PAPPh2 II (C0)3Fe-Hg-C6C15 I (MeO),Si The compounds [Rh(CECR)(HgPh)Cl(PPr\)2] have been prepared from trans-[RhCl(=C=C(SnPh,)R(PPr',),] and PhHgCl (R = Me Ph CH20H CH,OMe CMe,OH CH(Me)OH CH(Ph)OH SiMe, SnPh,).'60 A mercury atom has been shown to occupy the centre of a trigonal prism of platinum atoms in the 96 electron cluster [HgPt,(2,6-Me,C,H,NC)lz].XPS data and Hiickel calculations were also carried out."' A series of platinum-gold clusters [(Ph,P)Pt(AuPPh,),(HgX)] + (X = NO, C1 Br I Co(CO),) have been prepared and structurally characterized. Mercury was found to exchange reversibly with C0.'62 15' S. COCOand F. Mayor J. Organomet. Chem. 1994 464 215. 15' A. E. Mauro V. A. de Lucca Neto J. R.Zamian R. H. de Almeida Santos M. T. do Prado Gambardella J.R. Lechat and H. R. Rechenberg J. Organomet. Chem. 1994 484 13. 159 P. Braunstein M. Knorr M. Strampfer A. Tiripicchio and F.Ugozzoli Organometallics 1994,13,3038. I6O M. Baum N. Mahr and H. Werner Chem. Ber. 1994 127 1877. 16' Y. Yamamoto and H. Yamazaki Inorg. Chim. Acta 1994 217 121. R.A.T. Gould and L.H. Pignolet Inorg. Chem 1994 33 40.

ISSN:0260-1818    

DOI:10.1039/IC9949100115

出版商:RSC    

年代:1994

数据来源: RSC

摘要:

10 Inorganic and Organometallic Polymers By IAN MANNERS Department of Chemistry University of Toronto 80 St George St Toronto M5S lA1 Ontario Canada 1 Introduction Inorganic polymeric materials continue to attract considerable attention because of their interesting and unusual properties and also their potential applications as speciality materials. ’-’ This review focuses on developments in inorganic and organometallic polymer science published in 1994 and has the same format as and follows on from the three previous articles in the series which covered the years 1991 1992 and 1993.7-9 The first sections of the review cover new developments in the well- established inorganic polymer systems namely the polysiloxanes polyphosphazenes and p~lysilanes.~ A brief introduction to each of these classes of inorganic polymer systems was included in the appropriate sections of the first article of this ~eries.~ Following these sections recent developments concerning other polymers based on main-group elements and transition metals are discussed.As with previous articles in this the main emphasis is placed on polymers with inorganic elements within the main chain rather than in the side-group structure. In the past year other reviews on recent developments in the area of inorganic polymers have also been pub- lished.’’-’ 2 Polysiloxanes (Silicones) Polysiloxanes continue to be the focus of considerable attention particularly because of their liquid crystalline properties. ‘Silicon-Based Polymer Science’ed.J. M. Zeigler and F. W. G.Fearon Advances in Chemistry 224 American Chemical Society Washington D.C. 1990. ’ ‘Inorganic and Organometallic Oligomers and Polymers’ ed. R.M. Laine and J.F. Harrod Kluwer Publishers Amsterdam 1991. ‘Siloxane Polymers’ J. A. Semlyen and S.J. Clarson Prentice Hall Englewood Cliffs N.J. 1991. J. E. Mark H. R. Allcock and R. West ‘Inorganic Polymers’ Prentice Hall 1992. J. Inorg. Orgunomet. Polym. Plenum New York 1991-. I. Manners Polymer News 1993 18 133. ’ I. Manners Ann. Rep. Prog. Chem. Sect. A Inorg. Chem. 1991 88 77. I. Manners Ann. Rep. Prog. Chem. Sect. A Inorg. Chem. 1992 89 93. I. Manners Ann. Rep. Prog. Chem. Sect. A Znorg. Chem. 1993 90,103. lo I. Manners Adv. Muter. 1994 6 68. H. R.Allcock Adv. Mater. 1994 6 106.l2 M. Rosenblum Adv. Mater. 1994 6 159. 131 132 Ian Manners Functionalized polysiloxanes have attracted attention as sensing membranes for chemically modified field-effect transistors (CHEMFETs). The advantages of poly- siloxanes for this type of application revolve around their low glass-transition temperatures and high diffusion and permeability coefficients relative to other polymers. Reinhoudt and co-workers have prepared the series of polysiloxanes (1) via the ring-opening copolymerization of cyclotetrasiloxanes functionalized with polar cyanopropyl and cross-linkable methacryloxypropyl groups.' CN 9 F=O ,C=CH2 Me A siloxane membrane was cast on the gate area of a SO ion-sensitive layer field-effect transistor.The membrane was cast in THF and also contained the tetraethylester of calixC41arene as a sodium selective ionophore and a tetraphenylbor- ate derivative which introduced anionic sites. After solvent evaporation the mem- branes were cross-linked by exposure to UV light and were then covered by a layer of poly(hydroxyethylmethacry1ate) to eliminate CO interference and pH sensitivity. The CHEMFETs were found to show very good selectivity and sensitivity for sodium ions in the presence of other interfering ions such as Mg2+,K+,and Ca2+. The membranes showed significantly improved lifetime stability over plasticized poly(vinylch1oride) (PVC)-based systems with no decrease in selectivity or sensitivity when washed for 50 days in a stream of tap water. The polarity of membranes can be controlled by the amount of cyanopropyl groups in the copolymer.Furthermore the presence of methacrylate side-groups also offers the possibility of covalent attachment of the membrane to substrates. Zentel and co-workers have reported the synthesis and characterization of the first dimesogenic ferroelectric polysiloxanes (e.g.2).l4 Ferroelectric liquid-crystalline (LC) polymers with short switching times in electric fields are of considerable interest and also offer the possibility of the preparation of novel piezoelectric networks. Short switching times at ambient temperatures require low glass-transition temperatures which can be achieved with polysiloxanes. However to achieve low Tgsthe loadings of mesogenic side-groups must be reduced which results in a decrease in the stability of the LC-phase.Using dimesogenic side-groups in which two mesogen groups are linked together in one side-group allows the formation of stable LC-phases with a loading of only one dimesogen per 30 dimethylsiloxane repeat units. The polysiloxane (2) was found to possess a broad ferroelectric smectic S,*phase l3 H. Gankema R. J. W. Lugtenberg J. F.J. Engbersen D. N. Reinhoudt and M. Moller Adt.. Mater.. 1994. 6,944. l4 H. Poths and R. Zentel Macromol. Rapid Commun. 1994 15 433. Inorganic and Organometallic Polymers C02-(CH2)11-~ 1 \ 1 \ I Me R = CH2CHzCH2-CH NO2 from 99-141°C but the low temperature limit of this phase was limited by the occurrence of a higher ordered smectic phase (S,) from 62-99°C.The dimesogenic structure which increases the local concentration of mesogens clearly stabilizes this more ordered phase. However the value for the reduced polarization (Po)in (2) was found to be higher than in analogous monomesogenic polymers. The liquid crystalline behaviour of simple n-alkyl substituted polysiloxanes is also very interesting and has been studied in detail by Moller and co-workers." High molecular weight (M = ca. 10'-106) samples of poly(di-n-pentylsiloxane) poly(di-n-hexylsiloxane) and poly (di-n-decy1)siloxane were prepared by anionic (the first two) or cationic (the latter) ring-opening polymerization of the appropriate cyclotrisiloxanes. The phase behaviour of the polymers was studied by polarizing microscopy differential scanning calorimetry wide-angle X-ray scattering and solid state 29Si NMR.All three polysiloxanes formed a disordered mesophase before isotropization. Compared to poly(diethylsiloxane) the hexagonal mesophase for poly(di-n-hexyl- siloxane) is more stable. Thus the mesophase temperature interval is much greater for the latter (ca. 310 "C) than the former (ca. 43 "C). Optical polarizing microscopy indicated the presence of extended chain lamellae within this state. However in the case of poly(di-n-decylsiloxane) the conformationally disordered state was only observed by temperature-dependant 29Si chemical shift anisotropy measurements as an undercooled phase in coexistence with the high temperature crystalline phase. Novel ferroelectric side-chain liquid crystalline polysiloxanes showing bistable fast switching have also been reported by Kakimoto et al.16 The polymers (3) have been prepared via the polycondensation of the corresponding dichlorosilane with water.The dichlorosilanes were prepared via the hydrosilylation reaction of the olefin- terminated mesogen with dichloromethylsilane in the presence of chloroplatinic acid catalyst . The polymer molecular weights were in the range of 4.5 x 103-2.2 x lo4 and each polymer displayed an enantiotropic smectic A phase (S,) and broad chiral smectic C phase (S:) where the latter persisted below 20 "C.The switching in the oriented samples Is G. J. J. Out A. A. Teretskii M. Moller and D. Oelfin Macromolecules 1994 27 3310. '6 N. F. Cooray M. Kakimoto Y.Imai and Y. Suzuki Macromolecules 1994 27 1592. 134 Ian Manners had a response time of a few hundred microseconds the shortest time reported to date for liquid crystalline polymers. The spontaneous polarization of the polymers was in the range 32-122nC/cm2 at T -30°C (T is the S to Sz transition temperature). Other developments in polysiloxane chemistry have included the synthesis of bound ether-phosphines and their ruthenium complexes. l7 These sol-gel materials were characterized by solid state NMR and their catalytic properties were investigated. Photochromic liquid crystalline cyclic siloxanes (4) with pendent spiropyran groups have also been reported.' Cholesterol- and biphenyl-substituted mesogens were used as co-substituents. l7 E.Lindner M. Kemmler H.A. Mayer and P. Wegner J. Am. Chem. Soc. 1994 116 348. L. V. Natarajan T. J. Bunting and S. Y. Kim Macromolecules 1994 27 7248. Inorganic and Organometallic Polymers 3 Polyphosphazenes Polyphosphazenes are a remarkably diverse class of inorganic macromolecules and continue to attract considerable attention. New photo-crosslinkable polyphosphazenes (5) have been prepared via the introduction of chalcone substituents via macromolecular substitution reactions with polydichlorophosphazene.lThese polymers undergo [2 + 21 cycloaddition reactions in the presence of ultraviolet light. Poly (organophosphazenes) containing ally1 side-groups have also been prepared and their cross-linking and modification by hydrosilylation were studied.20 Allcock and co-workers have reported detailed studies of the first poly(monophos- phazophosphazenes).2 The materials were prepared via the thermal ring-opening polymerization of (trich1orophosphazo)pentachlorocyclotriphosphazene (at 150-1 80 "C) or (trich1orophosphazo)pentafluorocyclotriphosphazene(at 20&210") followed by nucleophilic substitution with organic nucleophiles alkoxy aryloxy alkylamino or arylamino side-groups.A feature of the substitution reactions is the greater ease of replacement of chlorine as compared to fluorine substituents. Full substitution of the chlorine substituents of (6) was achieved with trifluoroethoxide and n-propylamine but not with phenoxide or aniline. The analogous fluorinated polymer (7) only yielded a fully substituted polymer with trifluoroethoxide.Molecular weights (M,) of the organosubstituted polymers were ca. lo5with polydispersities of ca. 3. The moisture sensitive halogenated polymers (6) and (7)were amorphous with Tgsof -41 and -95 "C,respectively. The sharpness of the 31PNMR resonances for the polymers suggested that the microstructures were regular. l9 H. R. Allcock and C. G. Cameron Macromolecules 1994 27 3131. '' H. R. Allcock D. E. Smith Y. B. Kim and J. J. Fitzgerald Macromolecules 1994 27 5206. '' H. R. Allcock S. E. Kuharcik C. T. Morrissey and D. C. Ngo Macromolecules 1994,27 7556. 136 Ian Manners The polymerization mechanism is proposed to involve a cationic ring-opening polymerization in which the intiator is formed by ionization of a P-C1 bond of the exophosphazo group (Scheme 1).CI x = CI X=F or Scheme 1 Wisian-Neilson and co-workers have reported the complete deprotonation of poly (methylphenylphosphazene) which is generated by the condensation polymeriz- ation of phosphoranimines with methyl and phenyl substituents at phosphorus.22 The reaction generates the polymeric anion (8) via reaction of the polymer precursor with BuLi. The anion was found to be stable to +50°C and treatment with H20 regenerated poly(methylpheny1phosphazene)of similar molecular weight to the initial starting material. The intermediate (8) is likely to be an important development for the modification of poly(methylpheny1phosphazene) by deprotonation/substitution chemistry.For example the reaction of (8) with methyl iodide was shown to generate the polyphosphazene (9) with ethyl groups attached to 90% of the skeletal phosphorus 22 P. Wisian-Neilson C. L. Claypool and M. Bahadur Macromolecules 1994 21 7494. Inorganic and Organometallic Polymers atoms. The resulting polymer had a molecular weight (M = 7.2 x lo4,M,/M = 2.4) similar to that of the starting material poly(methylpheny1phosphazene) (M = 8.0 x lo4 M,/M = 2.3). Wisian-Neilson and co-workers have also reported the synthesis of nitro- amino- and N-amido-derivatives of poly(methylpheny1phosphazene)[e.g. (lo)] via an initial reaction which involves electrophilic substitution at the phenyl groups attached to phosph~rus.'~ In these reactions the phosphazene backbone demonstrated excellent stability to the vigorous chemical reactions.In other significant developments Hoyle et al. have reported detailed studies of the photophysics of poly(methylphenylph~sphazene).~~ In addition novel star-branched polymers with cyclophosphazene cores [e.g. (1 l)] have been synthesized." The methodology used to prepare these materials involved the use of hexakis(p-bromo-phenoxy) cyclotriphosphazene to initiate the polymerization of 2-methyloxazoline to produce a six-armed star (1 l),with a hydrophobic core and hydrophilic branches. 4 Polysilanes Polysilanes have continued to attract intense interest from both fundamental and applied perspectives. The remarkable properties of polysilanes are still a subject of widespread attention.23 P. Wisian-Neilson M. Bahadur J. M. Iriarte R. R. Ford and C.E. Wood Macromolecules 1994,21,4471. 24 C. E.Hoyle D. Creed P. Subramanian I. B. Rufus P. Chatterton M. Bahadur and P. Wisian-Neilson Macromolecules 1994 21 4605. 25 J.Y. Chang H.J. Ji M.J. Han S.B. Rhee S. Cheong and M. Yoon Macromolecules 1994 21 1376. 138 Ian Manners For example West and co-workers have reported studies of the influence of side-groups on the nature of the thermochromism exhibited by polysilanes.26 The polymers [RMeSi] were examined where R = Bunto n-dodecyl. The polysilanes with shorter than a c6 chain side-group showed a gradual bathochromic shift as the temperature was decreased. However an abrupt thermochromic transition was detected for the polymers with side-groups which were c6 or longer.The results were interpreted in terms of the dispersion interaction between delocalized a-electrons and the surrounding polarizable side-groups. Chiral poly(di-n-pentylsilane) copolymers (12) have been prepared by Frey Moller and Matyjaszewski via the copolymerization of (S)-2-methylbutyl substituted di- chlorosilanes with di-n-pentyldichloro~ilane.~ The copolymers showed high optical activities related to the a-6* transition in cyclohexane. Functional polysilanes have been prepared by Waymouth and co-workers28 via the free radical hydrosilylation of poly(phenylsi1ane) which is accessible via the transition metal catalysed dehydrogenative route to oligosilanes discovered by Harrod. A poly(phenylsi1ane) of molecular weight (M,) of ca.2000-4000 has been reacted with either olefins aldehydes or ketones to yield products with a variety of substituents bound to silicon through Six or Si-0 bonds. The hydrosilylation reactions were performed at elevated temperatures over 4-6h using either neat substrate or in 2,5-dimethyltetrahydrofuran using AIBN as initiator. A variety of pendant functional- ities were successfully attached such as ester dialkylamino alcohol and carboxylic acid groups (Scheme 2). Degrees of substitution of between 73-93% were observed. This synthetic breakthrough has permitted an analysis of the optical properties of polysilanes with alkoxy substituents. Pentoxy and cyclohexyloxy substituents have been found to give rise to red shifts of 59nm and 29nm respectively relative to poly(phenylsi1ane) for the a-o* transition for the Si-Si bond.Interestingly quarterniz- ation of the amino substituents or deprotonation of the carboxylic acid groups were shown to lead to water soluble polysilanes. 26 C. Yuan and R. West Macromolecules 1994 27 629. 27 H. Frey M. Moller and K. Matyjaszewski Macromolecules 1994 27 1814. 28 Y. Hsiao and R. M. Waymouth J. Am. Chem. SOC. 1994 116,9779. Inorganic and Organometallic Polymers Scheme 2 In other developments in polysilane chemistry 'polysi1astyrene'-polystyrene blends have been investigated and these materials have a range of interesting properties derived from the two homo polymer^.^^ 5 Other Polymer Systems Based on Main Group Elements The design synthesis and development of new polymer systems containing main group elements in the polymer main chain continues to attract attention.Polymers based on backbones of sulfur nitrogen and phosphorus atoms have been known since 1990 and developments in this area over the past four years have been reviewed.30 Full details of the synthesis and properties of poly(aminocarbophosphazenes)have been reported by Allcock and co-worker~.~~ These materials (13) were prepared by a ring-opening polymerization/nucleophilic substitution reaction sequence. CI CI CI 120"C $y=N-!=N-+=N+n CI CI CI YHR YHR +-7=N -y=N -y=N NHR NHR NHR 29 T. Asuke C. Yuan and R. West Macromolecules 1994 27 3023. 30 I. Manners Coord. Chem. Rev. 1994 137 109.31 H. R. Allcock S. M. Coley and C. T. Morrissey Macromolecules 1994 27 2904. 140 Ian Manners The homopolymers (13) were found to be hydrolytically sensitive but mixed substituent polymers (14) were found to be stable. Poly(pentakis (dimethy1amino)carbophosphazene)(1 5) was reported to undergo depolymerization in the solid state or in solution at room temperature. I I NHAr NMe NMe2 $y=N-y=N-P=Ntn NHAr NR2 NR2 NMe NMe NMe2 The interesting 2 1 periodic copolymers (16) have been prepared by Kobayashi and co-workers via the reaction of cyclic germylenes with p-benzoq~inones.~~ The 2 1 periodically regulated sequence is strikingly different from the 1 1 alternating structure previously prepared from the reaction of acyclic germanes and p-benzoquinones.(16) SiMe, I Nn T R'= or Y r SiMe SiMe The 2 1 copolymers (16) were isolated as fine white powders and were found to be soluble in organic solvents such THF and chloroform and insoluble in water. The values of M were ca. 6 x 104-3 x lo5 with polydispersities (M,/M,) of 2.g2.9.The mechanism of the copolymerization is not yet clear but it is postulated to occur via a radical pathway in which the dimer of the germylene which could exist in equilibrium with the monomer might react with the p-benzoquinone to give the 2 1 biradical intermediate (17). Successive radical coupling reactions could then lead to (16). Another possibility is that the propagation proceeds via the reaction of the 1 1 intermediate (18) with a further equivalent of germylene to give (19).A third possibility involves the reaction of the 2 1 biradical intermediate formed via the reaction of (18) with germylene.The polymer (16) could then be formed via the coupling of (19). The first details of the properties of poly(silaethy1ene) (20) a novel analogue of polyethylene have been reported by Interrante and co-worker~.~~ This polymer was prepared via the ring-opening polymerization of 1,1,2,2-tetrachlorodisilacyclobutane followed by reduction with Li[AlH,]. Poly(silaethy1ene) is air-stable soluble in 32 S. Kobayashi S. Iwata and M. Hiraishi J. Am. Chem. SOC.,1994 116 6047. 33 L.V. Interrante H. J. Wu T. Apple Q. Shen B. Ziemann D. M. Narsavage and K. Smith J. Am. Chem. SOC. 1994 116 12085. lnorganic and Organometallic Polymers organic solvents and has been well-characterized; typical molecular weight of the polymer without fractionation is M = 3.3 x lo4 M = 12 300.It has been found to convert into stoichiometric silicon carbide on pyrolysis to 1000°C and has been characterized by a variety of spectroscopic techniques and elemental analysis. In contrast to polyethylene which is a high melting solid even when a significant amount of chain branching is present poly(si1aethylene) is a viscous liquid at room temperature. On cooling to just below room temperature it forms a translucent white solid. Observations in a light microscope equipped with a cooling stage revealed a highly birefringent spherulitic pattern typical of a crystalline polymer.Differential scanning calorimetry showed distinct melting and crystallization transitions in the range -22 to 25 "C depending on the heating/cooling rate and the molecular weight of the sample used. The limiting value of T,, was indicated by a plot of the melting temperature versus molecular weight. This is much lower than that for polyethylene (1 38 "C). The glass transition for the uncrystallized portion of the poly(silaethy1ene) samples was found to be extremely low (T = -140"C),which is even lower than that for poly(dimethylsi1oxane) (T,= -123 "C) but is similar to that for poly(methy1hyd- rosiloxane) (T,= ca. -137 "C). ab initio Hartree-Fock 6-31 G* calculations were used to probe the mimic H,SiCH,SiH,CH,SiH to provide insight into the thermal transition behaviour.A relatively flat torsional surface was obtained with the all trans form as the global minimum. The surface was similar to but considerably flatter than that for the corresponding all-carbon backbone analogue n-pentane. The barrier for rotation about the internal Si-C bonds was found to be 4.5 kJmol-' compared to 14.6kJ mol- for n-pentane. This was attributed to the greater length of the Si-C (1.89A) and Si-H (1.49A) bonds compared to C-C (1.53 A) and C-H bonds (1.10A) 142 Ian Manners which significantly reduces the repulsive interactions between the substituents. The single chain statistics were explored using Monte Carlo methods. The results suggested that the characteristic ratio for poly(silaethy1ene) is lower than that for polyethylene and this suggests a higher entropy of fusion for the former which is consistent with its lower melting point.The crystallization and glass transition of poly(silaethy1ene) was followed by variable temperature solid-state NMR and the information obtained on motional properties interpreted in terms of the ab initio calculations. Sartori and co-workers have reported the photochemical chlorination of polycar- b~silanes~~ which gives materials such as (21). Halogen replacement with alkyllithium reagents was also described. Polymers with backbones of organodisilane units and thiophene units have been studied both theoretically and e~perimentally.~~-~~ These materials (22) were prepared via the sodium condensation of the corresponding 2,5-bis(chloro- sily1)thienylenes in decane.The polymers had molecular weights M of ca. 2 x lo4-3 x lo4 and M of 5 x lo3-7 x lo3. Photolysis in benzene resulted either in homolytic scission of silicon-silicon bonds or cross-linking. Triflate derivatives of other a-n-conjugated polymers polysilylacetylenes (23) have also been reported.38 The synthetic route to these polymers involves the reaction of ally1 derivatives with triflic acid. Analogous poly(oligosi1ane-diacetylenes) (24) and poly(disi1ane-oligophenylenes) (25) have also been synthesized and studied during the past Novel organosilicon dendrimers have been reported with redox active termini by Cuadrado and co-~orkers.~' Cyclic voltammetry of the dendrimers (26) showed one 34 W. Habel W.Haeusler and P. Sartori J. Organomet. Chem. 1994,483 183. 35 J. Ohshita T. Watanabe D. Kanaya H. Ohsaki M. Ishikawa H. Ago K. Tanaka and T. Yamabe Organometallics 1994 13 5002. 36 J. Ohshita D. Kanaya and M. Ishikawa J. Organomet. Chern. 1994 468 55. 37 K. Tanaka H. Ago T. Yamabe M. Ishikawa and T. Ueda Organometallics 1994 13 3496. 38 C. Tretner B. Zobel R. Hummeltenberg and W. Uhlig J. Organomet. Chern. 1994 468 63. 39 M. Fang A. Watanabe and M. Matsuda Chem. Lett. 1994 13. 'O B. Alonso I. Cuadrado M. Moran and J. Losada J. Chem. Soc. Chern. Commun. 1994 2575. Inorganic and Organometallic Polymers wave which indicated that all of the ferrocenyl moieties undergo oxidation at the same potential i.e. they are non-interacting. ) Me-Si-Me !JH NH f Chujo and co-workers h re reported the synthesis of pol forganoboron halides) (27) by hydroboration p~lymerization.~' The molecular weights of the materials were M = 500&23 000 as measured by GPC.These polymers show interesting reactivity as a polymeric Lewis acid. 6 Polymers Containing Skeletal Transition Metal Atoms Polymers containing skeletal transition metal atoms represent a rapidly growing area of research with a variety of interesting new developments reported in the past year. Poly(metallaynes) novel macromolecules (28) with backbones which possess conjugated CEC units and transition metal atoms (M) have been studied in some detail in the past few years and have been shown to possess interesting liquid crystalline properties and exhibit third-order non-linear optical behaviour.Lewis Marder and Friend have reported detailed optical spectroscopic studies of the platinum acetylide polymers in 1994.42 41 Y. Chujo N. Takizawa and T. Sakurai J. Chem. SOC. Chem. Commun. 1994 221. 42 M.S. Khan A. K. Kakkar N. J. Long J. Lewis P. Raithby P. Nguyen T. B. Marder F. Whittmann and R.H. Friend J. Mater. Chem. 1994,4 1227. 144 Ian Manners Analogous ruthenium(I1) systems (29) have been similarly synthesized and full details of their preparation have been reported.43 Further advances have also been reported concerning high molecular weight poly(ferrocenylsilanes) (30) which were first synthesized in 1992 by a ring-opening polymerization route. Progress to date in this field was briefly reviewed in early 1994." Also polymers which are unsymmetrically substituted at silicon have been synthesized and ~haracterized.~~ These materials show interactions between the skeletal iron centres that are similar to their symmetrically substituted analogues.Thus the electrochemical behaviour of these materials was investigated by cyclic voltammetry and two oxidation waves consistent with the presence of significant interactions between the iron centres were identified. The cyclic voltammogram of (30) (R' = Me 43 C.W. Faulkner S. L. Ingham M. S. Khan J. Lewis N. J. Long and P. R. Raithby J. Organomet. Chem. 1994 482 139. 44 D. A. Foucher R. Ziembinski R. Petersen J. Pudelski M. Edwards Y. Ni J. Massey D. R. Jaeger G.J. Vancso and I.Manners Macromolecules 1994 27 3992. Inorganic and Organometallic Polymers 145 R2 = Fc) with ferrocenyl and methyl side groups at silicon was more complex and indicated that interactions exist between the iron centres in the polymer backbone and the metallocenyl side-groups. The unsymmetrically substituted polymers were gen- erally amorphous but those with methyl and hydrogen substituents showed two weak melting transitons. Also long n-alkyl side groups were crystallized. For example the poiy(ferrocenylsi1ane) (30) with a C, substituents at silicon was found to possess a melting transiton at + 16"C.Subsequent to the publication of this work an additional report of the synthesis and properties of (30) (R' = Me R2 = Fc) was made.45 heat e L -1" Very interesting studies of oxidized low molecular weight (M = ca.1500) poly(ferrocenylsi1anes) with an average number of repeat units of five which were generated via condensation routes have been reported by Garnier and co-~orkers.~~ In the case of the tcne (tcne = tetracyanoethylene) oxidized di-n-hexyl-substituted material (30) (R' = R2 = n-hexyl) paramagnetic behaviour was observed above T = T = 20 K but below this temperature ferromagnetic interactions occurred and a spin glass formed with complete blocking of spins at TG= 8 K. The magnetization was found to vary linearly with applied field above T, which is typical of paramagnetic behaviour but below T the magnetization increased rapidly with applied field and the magnetization curve as a function of applied field exhibited a hysteresis cycle characteristic of ferromagnetic interactions.The oxidized di-methyl-substituted ma- terial (30) (R' = R2 = Me) revealed similar ferromagnetic behaviour at low tempera- tures. Interestingly the partially (tcne) oxidized di-n-hexyl material is localized on the Mossbauer time-scale at 80K but delocalized at room temperature. Thus at 80K two quadrupole doublets characteristic of Fe" and Fe"' centres were detected. By contrast at room temperature a single quadrupole doublet was detected which is characteristic of a delocalized mixed-valence state. In contrast to the organosilicon spacer in poly(ferrocenylsilanes),the presence of a rigid quinoid-type terthienyl bridge appears to hinder cooperative interactions between spin bearing transition metal centres and only weak antiferromagnetic interactions were detected at low temperatures.Considerable progress was reported in 1994 on the use of anionic ring-opening polymerization methods to prepare poly(ferrocenylsi1anes) in solution at room temperat~re.~~.~~ In early 1994 it was reported that the reaction of the silicon-bridged [llferrocenophane (31) (R' = R2 = Me) with equimolar quantities of ferrocenyl- 4s K. B. Pannell V. V. Dementev H. Li F. Cervantes-Lee M. T. Nguyen and A. F. Diaz Oryanometallics 1994 13 3644. 46 M. Hmyene A. Yassar M. Escorne A. Percheron-Guegan and F. Garnier Adv. Muter. 1994 6 564. 47 R. Rulkens A.J. Lough and I. Manners J. Am. Chem. Soc. 1994 116 797. 48 R. Rulkens Y.Ni and I. Manners J. Am. Chem. Soc. 1994 116 12 121. 146 Ian Manners lithium yields oligomers with up to nine ferrocene units. These were separated via column chromatography and the species with five ferrocene units (32) was success- fully studied by single-crystal X-ray diffraction. The oligomers were studied by electrochemistry and function as excellent models for the electrochemistry of the corresponding high polymer. In addition the structure of the oligomer which possesses a trans-planar zigzag conformation provides valuable information on the possible structure of the high polymer. If (31) (R' = R2 = Me) is reacted with small quantities of an anionic initiator poly(ferrocenylsi1anes) are formed.47 Subsequent to this work two reports of the X-ray structure of the shorter oligomer (33) with three ferrocene units were p~blished.~~?~~ M (32)x =3 (33)x=l In late 1994 the living nature of the anionic ring-opening polymerization using initiators such as Bu"Li was described.48 This permits the control of polymer molecular weight and the synthesis of poly(ferrocenylsi1anes) with narrow molecular weight distributions.By reaction of the living polymeric anions with cyclic siloxanes the first examples of block copolymers containing skeletal transition metal atoms (34) were prepared. Me I .Si-Me Y BSi-Bu Me Jm Full details of the synthesis and ring-opening polymerization of germanium-bridged [llferrocenophanes were reported in 1994.50 The strained germanium-bridged [llferrocenophane was found by single-crystal X-ray diffraction to possess a tilt angle of 19.0(9)'.A series of symmetrically-substituted poly(ferrocenylgermanes) (35) (R = Me Et Ph) have been prepared by the thermal ring-opening polymerization of the appropriate strained precursors and were found to possess M = ca. lo6 and 49 A. J. Lough I. Manners and R. Rulkens Acta Crystallogr. Sect. C 1994,50 1667. 50 D. A. Foucher M. Edwards R. A. Burrow A.J. Lough and I. Manners Organometallics 1994,13,4959. Inorganic and Organometallic Polymers M = ca. lo5.Details of the thermal transition behaviour of poly(ferroceny1germanes) were also published in 1994.51 r 1 The synthesis and ring-opening polymerization of the first [2]ruthenocenophanes was also reported in 1994.52These species were prepared via the reaction of the salts Li,[(C,H,RCH),] (R = H or Me) with cis-[RuCl,(DMSO),].The species (36) (R = H) was found to possess the most ring-tilted structure for any neutral [nlmetallocenophane to date (29.6'). Thermal ring-opening polymerization occurred in the melt at ca. 220 "C and afforded the poly(ruthenocenylethy1enes)(37) (R = H or Me). The polymer (37) (R = H) was insoluble in organic solvents but the methylated analogue (37) (R = Me) was soluble and possessed a bimodal molecular weight distribution with M = ca. 4.3 x lo4 and M = 1.3 x lo4for the highest molar mass fraction. The oxidative stability of the poly(ruthenocenylethy1enes) was shown by cyclic voltammetry to be greater than for the analogous iron-containing poly(ferrocenylethy1enes).Unsuccessful attempts to polymerize a range of [n]metallocenophanes were also reported in 1994.53*54 For example siloxane-bridged [nlferrocenophanes [e.g. (38)] and disilane-bridged and bis-disilane-bridged C2lruthenocenophanes [e.g. (39)] have been synthesized and were found to be resistant to thermally-induced ring-opening polymerization. This was attributed to the relatively low degree of strain present in these molecules. Significant developments concerning polyferrocenylene persulfides have also been described by Rauchfuss and co-~orkers.~ These polymers were first synthesized in 51 D. A. Foucher R. Ziembinski R. Rulkens J. M. Nelson and I. Manners in 'Inorganic and Organometallic Polymers 11' American Chemical Society 1994 572 449.52 J. M. Nelson A.J. Lough and I. Manners Angew. Chem. Int. Ed. Engf. 1994 33 989. s3 C. Angelakos D. B. Zamble D. A. Foucher A. J. Lough and I. Manners Inorg. Chem. 1994,33 1709. 54 J. M. Nelson A. J. Lough and I. Manners Organometallics 1994 13 3703. 55 D. L. Compton and T. B. Rauchfuss Organometallics 1994 13 4367. 148 Ian Manners Me 1992 by a novel sulfur-abstraction induced ring-opening polymerization route. The atom abstraction route using PBu as desulfurization agent has now been extended to the preparation of polymers with one or two t-butyl substituents bound to the cyclopentadienyl rings. Trisulfide-bridged [3]ferrocenophanes with one or two t-butyl substituents attached to the cyclopentadienyl rings have been prepared and the latter was characterized by single crystal X-ray diffraction.The tilt-angle between the planes of the cyclopentadienyl ligands was found to be only ca. 4" which indicates that the molecule is unstrained. Treatment of (40) and (41) with PBu yielded the poly(ferrocenylenepersu1fides)(42). The desulfurizations were more rapid for the mono t-Bu substituted monomer than the corresponding species with two But substituents and the reactions proceeded more quickly in DMF than THF. Materials with molecular weights M = 2.6 x lo4 and M = 3.7 x lo3 and M = 1.9 x lo4 and M = 2.4 x lo3 were formed which are lower than that found for the Bun substituted poly(ferrocenylenepersu1fide).The formation of a polymer in DMF was accompanied by the formation of an insoluble material which was identical to the soluble material within the errors of elemental analysis.The corresponding desulfurization reactions in CH,CI gave only low molecular weight products. Fast-atom bombardment mass spectra of (42) R = H showed molecular ions for species up to an oligomer with 16 repeat units. Thermogravimetric analysis under helium showed that the polymers are stable to weight loss up to ca. 260-290°C at a heating rate of lO"C/min. The yellow polymers are stable to air in the solid state and were found to be sensitive to light. NMR studies of the polymers provided useful insight into the stereochemistry of the polymers. The di But substituted polymer has a repeat unit with C symmetry and has two stereochemically distinct dyads the homochiral and heterochiral pairs.Based on 'H NMR analysis these are present in approximately equal amounts. The situation for the monosubstituted But polymer is more complex with a disymmetric repeat unit and a total of six stereochemically distinct dyads being possible. Electrochemical studies of the polymers are consistent with initial oxidation at alternating iron sites with two reversible oxidation waves detected (separation = ca. 0.29 V). Interesting mechanistic insight was provided by the reaction of (43) which possesses a selenium atom in the central position of the bridge with PBu,. This led to exclusive abstraction of the selenium atom to give (42) and Se=PBu and indicated that the polymerization proceeds via removal of the central chalcogen atom in the [3]ferrocenophane monomer.The steps shown in the sequence (40 41)+(42) might (or might not) involve a strained disulfide bridged [2]ferrocenophane. Polymers which contain ferrocene groups in the side-group structure have also received continued attention. For example thermally responsive and electroactive Inorganic and Organometallic Polymers R;&yS-S -PBU I Fe .s -n (40) R' =But R2=H (41) R' = R2 = But poly(N-acryloylpyrro1idine)-poly(viny1ferrocene) copolymers (44) have been syn- thesized and studied.56 These are water soluble but show a lower critical solution temperature (LCST) above which they precipitate as a gel. The LCST of the copolymers was found to decrease with increasing ferrocene content.Oxidation of the ferrocene units with Ce" yielded more hydrophilic copolymers and L-ascorbic acid was used to rereduce the Fell1 polymers. Other areas of transition metal polymer chemistry are also attracting attention. For example Puddephatt and co-workers have described the synthesis of novel den- drimeric organoplatinum complexes (45).5These materials which possess up to 28 platinium atoms were prepared by the oxidative addition of precursors containing a dimethylplatinum(I1) centre to 1,2,4,5-tetrakis(bromornethyl)benzene. Fox and co-workers have reported the synthesis and properties of coordination polymers (46).58The electric conductivities of these materials were found to be much lower than in dithiolene analogues where delocalization through the interaction of the unpaired electrons on sulfur with a vacant d orbital on the metal ion was possible.N. Kuramoto Y. Shishido and K. Nagai Macromol. Rapid Commun. 1994 15 441. '' S. Achar and R. J. Puddephatt J. Chem. SOC.,Chem. Commun. 1994 1895. '' P. Wang and M. A. Fox Inorg. Chem. 1994 33 2938. 150 I an Manners (46) M = Nil Pd Pt Another interesting synthetic route to novel organometallic polymers was reported by Endo et aL5’ This route involves the synthesis of a cobaltacyclopentadiene polymer (47) which undergoes thermal rearrangement to yield a polymer with cyclo-butadienecobalt centres in the main chain. Number average molecular weights of ca. 33000 were measured for (47) using gel permeation chromatography.59 I. Tomita A. Nishio and T. Endo Macromolecules 1994 27 7009. Inorganic and Organometallic Polymers I + Ph-CEC-R-CEC-Ph co Ph3P' 'PPh

ISSN:0260-1818    

DOI:10.1039/IC9949100131

出版商:RSC    

年代:1994

数据来源: RSC