摘要:

Trinuclear Niobium Oxide Clusters1). – Synthesis of (η5‐C5Me5)3Nb3(μ2‐O)3(μ3‐O)(μ2‐Cl)Cl3and [(η5‐C5Me5)3Nb3(OH)2(μ2‐OH)(μ3‐OH)(μ2‐O)2(μ3‐O)Cl]ClHydrolysis of η5‐C5Me5NbCl4with excess of water leads to a mixture of products. Pyrolysis of this crude mixture gives (η5‐C5Me5)3Nb3(μ2‐O)3(μ3‐O)(μ‐Cl)Cl3(1) in good yield. On treatment of1with water [(η5‐C5Me5)3Nb3(OH)2(μ2‐OH)(μ3‐OH)(μ2‐O)2(μ3‐O)Cl]Cl (2) is obtained. The products1and2were chara

ISSN:0009-2940    

DOI:10.1002/cber.19911240202

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Coordination Ability of Alkynylphosphines RnP(CC – R')3 –nAlkynylphosphines RP(CC–R')2(2) react with one equivalent of octacarbonyldicobalt to yield selectively the η2‐μ side‐on‐coordinated alkyne complexes (R)(R' – CC)P[(η2‐CC–R')Co2(CO)6] (6); with another equivalent of Co2(CO)8the dicoordinated compounds (R)P[(η2‐CC–R')Co2(CO)6]2(7) are obtained.7may also be synthesized directly by the reaction of2with two equivalents of Co2(CO)8. However, P(CC–Ph)3yields with two equivalents of Co2(CO)8the cyclic Co2P2C2system {(Ph–CC)(R')P[(η2‐CC–Ph)Co2(CO)5]}2(4) [R' = (η2‐CC–Ph)Co2(CO)6]. Decarbonylation of6agives the six‐membered cyclic compound {(Ph)(Ph – C  C)P[(η2‐C  C – Ph)Co2(CO)5]}2(8), while6byields the cluster Co3(CO)9(μ3‐PtBu) (9). The structure

ISSN:0009-2940    

DOI:10.1002/cber.19911240203

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Transition‐Metal‐Substituted Diphosphenes, XX1). – Synthesis and Properties of the Tetrahedrane [(η5‐C5Me5)(CO)2‐FeP–PtBu]Fe2(CO)6and the Metalated 1,3‐Diphospha‐2‐propanones [(η5‐C5Me5)(CO)2Fe–PC(O)–PR]Fe2(CO)6[R =tBu, 2,4,6‐(CF3)3C6H2]The reaction of [η5‐C5Me5)(CO)2FeP(SiMe3)2(1) withtBuPCl2(2a) affords the metalated cyclotetraphosphane [(η5‐C5Me5)‐(CO)2FeP–PtBu]2(4a) besides the metal‐substituted cyclotriphosphane (η5‐C5Me5(CO)2Fe–P[PtBu]2(5a) and the diphosphane (η5‐C5Me5)(CO)2FeP(SiMe3)P(Cl)tBu (3a), which are detected in the reaction mixture by31P‐NMR spectroscopy. Treatment of4awith excess of Fe2(CO)9leads to the tetrahedrane [(η5‐C5Me5)(CO)2FeP–PtBu]Fe2(CO)6(6a) and the 1,3‐diphospha‐2‐propanone derivative [(η5‐C5Me5)(CO)2FePC(O)‐P–tBu]Fe2(CO)6(7a). Similarily, an analogous complex7cis obtained from the reaction of in situ prepared

ISSN:0009-2940    

DOI:10.1002/cber.19911240204

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe title compound phosphabutatriene possesses two energetically closely spaced frontier orbitals, as in methylenephosphane and in phosphaallene. They are built up from the π system or the s̀ orbital of phosphorus by interaction with neighboring π bonds. The extension of these frontier orbitals over all (heavy) atoms makes self‐dimerization to different cyclobutane derivatives feasible. Substituent effects on the ordering of s̀ and π are analyzed. Vibrational analyses indicate PC vibrations of low intensity which decrease with increasing length of the heterocumulene chain. The analysis is extended to the two next higher homologs, which are hitherto experimentally

ISSN:0009-2940    

DOI:10.1002/cber.19911240205

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe tris(borane) adduct MeC(CH2PMe2BH3)3(2) of 1,1,1‐tris‐[(dimethylphosphino)methyl]ethane has been prepared from the tripodal phosphane and Me2S–BH3as the borane source. The crystal structure of 2·1/2 toluene has been determined by single‐crystal X‐ray diffraction methods. The molecules display crystallographic C3symmetry and an overall staggered conformation. In an analogous way the bis(borane) adduct CH2(PH2BH3)2(3) of 1,3‐diphosphapropane has been synthesized, which decomposes above 50°C to give insoluble products, whose elemental analysis indicated that termal P–C bond cleavage is more frequent than P

ISSN:0009-2940    

DOI:10.1002/cber.19911240206

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Reactions of Ga2Br4· 2 Dioxane with (Trimethylsilyl)methyllithium and Neopentyllithium — Synthesis and Molecular Structure of Lithium Tetraalkylgallanates(III) with Li–C–Ga BridgesGa2Br4· 2 dioxane reacts with (trimethylsilyl)methyllithium or neopentyllithium to yield inn‐pentane/diethyl ether solution besides elemental gallium exclusively the disproportionation product trialkylgallane. In puren‐pentane the dioxane adducts of the corresponding lithium tetraalkylgallantes (R = CH2SiMe32; R = CH2CMe34) are formed.2and4are also synthesized by the reaction of GaBr3with alkyl lithium in the molar ratio 1:4. The crystal structure of2shows a dioxane‐bridged dimer and Li–C–Ga bridges with lithium probably bound by the C–H s̀‐bonds o

ISSN:0009-2940    

DOI:10.1002/cber.19911240207

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Cycloaddition Reactions of Organometallic Complexes, XII1). – Ketenimines from Isocyanides and Diazoalkanes: A New Cobalt‐Assisted C–C Bond Forming ReactionThe compounds C5H5Co(CNR)(PMe3) (1–3) react with diaryl‐diazomethanes (X)(Y)CN2to give theC,C‐bound ketenimine cobalt complexes C5H5Co[η2‐C,C‐RNCCXY] (PMe3) (4–9), while the reaction of1–3with 9‐diazofluorene leads to the formation ofN,C‐bound ketenimine complexes C5H5Co[η2‐N,C‐RNCC(C12H8)](PMe3) (11–13). The different bonding modes of the ketenimine ligands in4–9and11–13, indicated already by the significantly different spectroscopic data, are shown by the X‐ray structural analysis of9‐RCoSC(R = CHMePh; X and Y = 4‐ClC6H4) and12(R = C6H11). On treatment of compounds4, 6–9, 11, and13with an equimolar amount of iodine, free ketenimines are generated. The by‐product C5H5Co(PMe3)I2can be transformed into the starting materials1–3in two steps

ISSN:0009-2940    

DOI:10.1002/cber.19911240208

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Crystalline Tl2B2H9C2Me2: Synthesis and Solid State Structure; a Contribution to the Problem of Tl(I)–Tl(i) InteractionsCrystalline Tl2B9H9C2Me2(1) is obtained in the reaction of the carborane B9H11C2Me2with two equivalents of thallium(I) ethanolate. An X‐ray diffraction study of1shows – contrary to the expectation – the presence of isolated thallium ions and thalladicarbollide counteranions. The latter represent ion pairs composed of Tl(I)+and B9H9C2Me212−units forming slipped icosahedrons. All possible Tl–Tl distances in1are too long for even weak attractive interactions, with one exception: A set of symmetry‐equivalent cations possesses a Tl–Tl distances of 3.67 A, which is in a range postulated by calculations f

ISSN:0009-2940    

DOI:10.1002/cber.19911240209

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Metal Atoms in the Synthesis of Metal Clusters, II1). – Reactions of Substituted Cyclopentadienes and Nickelocene with Nickel and Iron AtomsBy vaporizing nickel atoms into solutions oftert‐butyl‐substituted cyclopentadienes in methylcyclohexane mononuclear sandwich compounds (1, 4, and6as main products) as well as tri‐ and tetranuclear clusters are prepared. With mono‐ and di‐tert‐butyl‐substituted cyclopentadienes as ligands the new clusters2and5are obtained. In the reaction with 1,2,4‐tri‐tert‐butylcyclopentadiene6is the only observed product. Hindered rotation around the metal‐ligand bond vector is observed for4even at room temperature. When treating1with nickel atoms cluster2is formed, indicating some importance of1during the formation of2in the above reaction. Clusters2and5contain hydrido ligands, which could be identified in the case of tris(1,3‐di‐tert‐butyl‐η5‐cyclopentadienyl)trinickel dihydride (5) by a single crystal structure determination as μ3‐H bridges. A tetrahedral structure is found for the cluster2by X‐ray crystallography. With the aid of MS, IR, magnetic measurements, and cyclovoltammetric investigations2is identified as a mixture of2aand2bbearing one or three bridging hydrogens, respectively. In general2a, 2b, and5show a rich redox chemistry with reversible redox couples between –2 and +2. Reaction of iron atoms, nickelocene, and mesitylene in methylcyclohexane at −120°C leads unexpectedly to cluster3, tetrakis(η5‐cyclopentadienyl)tetranickel trihydride and a not yet identified (η5‐cyclopentadienyl)mesityleneiron comp

ISSN:0009-2940    

DOI:10.1002/cber.19911240210

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractReactions of (η5‐C5H5)Re(NO)(PPh3)(SiMe2H) (1) and CHCl3, CBr4, and CHI3give halosilyl complexes (η5‐C5H5)Re(NO)‐(PPh3)(SiMe2X) [X = Cl (2), Br (3), I (4); 66–84%]. Addition of Me3SiOTf to 2 gives triflate (η5‐C5H5)Re(NO)(PPh3)(SiMe2OTf) (5; 97%), which in turn reacts with (Me2N)3S⊕[SiMe3F2]⊖to give (η5‐C5H5)Re(NO)(PPh3)(SiMe2F) (6; 77%). Reaction of5and pyridine gives the base‐stabilized silylene complex [(η5‐C5H5)Re(NO)(PPh3){SiMe2(NC5H5)}]⊕TfO⊖(7; 84%). CH2Cl2solutions of (η5‐C5H5)Re(NO)(PPh3)(CH3) (8) or2and Lewis acids are studied by IR and NMR. As assayed by IR,8/ECl3solutions (E = B, Al) show ReNO–ECl3(major) and Re–ECl3(minor) adducts. Solutions of 2/BCl3show analogous adducts (‐78°C), and in the presence of excess BCl3(η5‐C5H5)Re‐(NO–BCl3)(PPh3)(SiMe2Cl) (11) crystallizes. Solutions of2/AlCl3show uncomplexed2and Re–AlCl3(major) and ReNO–AlCl3(minor) adducts. In contrast to2–7and 2/BCl3,1H‐ and13C‐NMR spectra of2/AlCl3suggest an equilibrium with the base‐fr

ISSN:0009-2940    

DOI:10.1002/cber.19911240211

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY