摘要:

AbstractThe elements oxygen, sulfur, and selenium add to the P atom of the title borane1. In contrast to the formation of tmpBNP(X)tBu2(X = S, Se), thePoxide (X = O) dimerizes to [tmpBNP(O)tBu2]2(5) with an eight‐membered flat boat‐shaped B2N2P2O2ring. Borane1reacts readily with Mel to yield a phosphonium salt8and with BBr3to give an adduct9with a BP bond. In contrast, bis(dichloroboryl)‐methane not only adds to1to generate a coordinate BP bond but also chloroborates the BN triple bond, the final product being a new five‐membered heterocycle10. Similarly, the BH3component of BH3·SMe2first adds to the P atom of1followed by reaction of a second mol of BH3·SMe2which hydroborates the BN triple bond. Finally, metal carbonyl fragments add only to the P atom of1, demonstrating also that the chemistry of the molecule1is dominated by

ISSN:0009-2940    

DOI:10.1002/cber.19951280302

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe methylidene complex [(η5‐C5H5)Re(NO)(PPh3)(CH2)]+PF −6or the ReCD2analog react with diazo compounds N2CHR [R  H, Si(CH3)3, COPh, CO2C2H5] in CH2Cl2at −80°C to give alkene complexes [(η5‐C5H5)Re(NO)(PPh3)(η2‐H2CCHR)]+PF −6or D2CCHR analogs. The two ReC geometric isomers of benzylidene complex [(η5‐C5H5)Re‐(NO)(PPh3)(CHPh)]+PF −6and CH2N2react to give opposite configurational diastereomers of styrene complex [(η5‐C5H5)Re(NO)(PPh3)(η2‐H2CCHPh)]+PF −6. Stereochemical features of these reactions are analyzed in detail, and are interpreted in terms of models involving (a) attack of the diazo compound upon the ReC face opposite to the bulky PPh3ligand, (b) an antiperiplanar disposition of the ReC and CN2bonds in the transition state, utilizing the diazo carbon face that minimizes interactions of the substitutent (R) and cyclopentadienyl ligand, and (c) N2loss from the resulting intermediate [(η5‐C5H5)Re(NO)(PPh3)(CHR′CHRN2)]+PF −6via a conformer with antiperiplanar PReCHR′C and ReCHR′CHRN linkages

ISSN:0009-2940    

DOI:10.1002/cber.19951280303

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractA series of new titanium complexes of the general type Ti(mbmp)X2(X = Br, I; OMe, OiPr, OtBu), containing a bidentate bis(phenoxy) ligand derived from 2,2′‐methylenebis(6‐tert‐butyl‐4‐methylphenol) (mbmpH2), was prepared. The1H‐chemical shifts for the protons of the methylene link were found to vary considerably as a function of the ligand X. Reaction of Ti(OiPr)4with two equivalents of mbmpH2gave theC2‐symmetric spiro‐titanate complex Ti(mbmp)2. The crystalline labile solvent adducts of the dichloro complex Ti(mbmp)Cl2with THF and DME were isolated and characterized. A single‐crystal X‐ray structural analysis revealed the THF adduct to be a mono(THF) adduct with a trigonal‐bipyramidal configuration, the bidentate mbmp ligand spanning an apical and equatorial site and the THF ligand occupying the re

ISSN:0009-2940    

DOI:10.1002/cber.19951280304

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractWater‐soluble manganese(III) as well as iron(III) porphyrinates are introduced as light‐sensitive precursor compounds for the photocatalytic activation of dioxygen in aqueous solutions. It is shown that in the presence of α‐pinene (4) and the further cycloalkenes11–13photocatalytic oxygenation reactions occur. The dependence of the selectivity of the oxygen transfer to the olefin on both the presence of water and the variation of the substrate‐to‐catalyst ratio is discussed. The catalyst may be conveniently separated from the substrates/products by using aqueous sol

ISSN:0009-2940    

DOI:10.1002/cber.19951280305

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe 1:2 manganese (5), nickel (6), and copper complex (7) with the novel dihydrobis(1,2,4‐triazolyl)borate ligand (2) were synthesized and structurally characterized. Single‐crystal X‐ray studies reveal the formation of highly solvated coordination polymers of the formula {[M(H2O)2{μ‐H2B(C2H2N3)2}2] ·nH2O}∞for M = Mn and Cu. In5(M = Mn;n= 4) a two‐dimensional metal‐ligand framework is built by means of the bridging action of2.These metal‐ligand grid sheets sandwich water layers which comprise individual six‐membered rings. Compound7(M = Cu;n= 6) can be described as a linear metal‐ligand chain with two borate ligands bridging two copper centers. These one‐dimensional coordination polymers are separated by one‐dimensional arrays of water molecules in the form of edge‐sharing six‐membered rings. In both structures the water of crystallization is held in place both by hydrogen bonding from the aqua ligands and by hydrogen bonding to the nitrogen atoms of the borate ligand. Bis[hydrotris(1,2,4‐triazolyl)borato]nickel, [Ni{HB(C2H2N3)3}2] (8), was obtained from NiCl2and the potassium salt of [HB(C2H2N3)3]−(1). Single‐crystal X‐ray structures of the solvate8· 6 H2O were determined at 293 and 160 K. The water molecules are arranged in two‐dimensional layers with only weak (hydrogen bonding) interactions to the adjacent layers of the complex molecules. The room temperature structure (orthorhombic, space groupCmca) shows a highly disordered water structure being indicative of a dynamic equilibrium between small conglomerates and free molecules. Upon cooling an ordering occurs in the water layer leading to a phase transition in the crystal, and in the low‐temperature structure at 160 K (orthorhombic, space groupPmnb) the hydrogen atoms and bonding network of the water structure could be determined. This structure is best described as being composed of individual rings or chain segments. The material surface morphology after loss of the water of crystallization was studied by scanning electron microscopy and the structural p

ISSN:0009-2940    

DOI:10.1002/cber.19951280306

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

Imidazole Derivatives, XIII. – Carbene Complexes of Silicon and TinHerrn ProfessorPeter Paetzoldzum 60. Geburtstag gewidmet.Stable adducts of the composition L · SiCl4(2), L · SiR2Cl2(3,4), and L · SnR2Cl2(6) are formed by the reaction of the imidazol‐2‐ylidenes L (1) with the corresponding silicon and tin halides. For L = SiCl4(2b; L = 1,3‐diethyl‐4,5‐dimethylimidazol‐2‐ylidene) and L · SnPh2Cl2(6c; L = 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) the monomeric nature of the compounds containing pentacoordinated silicon and tin is established by X‐ray structure analyses. The reaction of 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene (1c) with SnCl2leads to the formation of the monomeric stannylene complex L · SnCl2(7c; L = 1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) whose molecular geometry indicates

ISSN:0009-2940    

DOI:10.1002/cber.19951280307

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

PnLigands with Maximum Electron‐Donor Capacity, 7. – Three‐Component Reaction of P4‐Phosphorus with [CpxRh(CO)2] in the Presence of [Cr(CO)5THF] or [CpMn(CO)2THF]. – A Method of Studying the Pathway from Tetrahedral P4to the Planarcyclo‐P4LigandHerrn ProfessorGerhard Fritzzum 75. Geburtstag gewidmet.The reaction of P4with [CpxRh(CO)2] (Cpx= Cp′, Cp′′; Cp′ = η5‐C5H4tBu, Cp′′ = η5‐C5H3tBu2‐1,3) in the presence of [Cr(CO)5THF] leads to [CpxRh(CO)(η1:1‐P4){Cr(CO)5}4] (1a, b), [Cp′′Rh(η4‐P4){Cr(CO)5}3] (2b), and [Cp′Rh(η4‐P4){Cr‐(CO)5}4] (3a). In the corresponding reaction with [CpMn‐(CO)2THF] no P4takes part, and [(Cp′′RhCO)(CpMnCO)(μ‐CO)2] (4) is formed. An X‐ray structure determination of [CpxRh(CO)(η1:1‐P4){Cr(CO)5}4] (1) and [Cp′Rh(η4‐P4)‐{Cr(CO)5}4] (3a) indicates a stepwise (PP) bond cleavage as the transformation pathway from the P4tetrahedron to thecyclo‐P4ligand by passing a bicyclotetraphosphane. In thecyclo‐P4ligand complex3aall P atoms are able to coordinate to [Cr(CO)5] groups. However, in [Cp′′Rh(η4‐P4){Cr(CO)5}3] (2b) the additionaltBu group at the Cpxligand sterically influences the coordination behavior of the P atoms, and only three of them are able to coordinate to [Cr(CO)5] units. In these syntheses the [Cr(CO)5] moieties promote the reaction and stabilise intermediates along the reaction pathway. Variable‐temperature31P{1H}‐NMR measurements indicate for2bthe freezing of the Cp′′ rotation at low temperature and reveals a ΔG ≠c(at the coalescence temperature) of 36 kJ mol−1. Surprisingly, in [(Cp′′RhCO)(CpMnCO)(μ‐CO)2]‐(Rh‐Mn) (4) the Cpxligands arecis‐oriented whereas in [(Cp*RhCO)(CpMnCO)(μ‐CO)2](Rh‐Mn) atransarrangement is observed. This indicates the unusual behavi

ISSN:0009-2940    

DOI:10.1002/cber.19951280308

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

Synthesis and Characterisation of Stable Bis(phosphonio)isophosphindolyliumcarbonylmetallates and a Cationic Bis(phosphonio)isophosphindolylium‐Gold ComplexHerrn ProfessorAlfred Schmidpeterzum 65. Geburtstag gewidmet.Reaction of 1,3‐bis(triphenylphosphonio)isophosphindolylium bromide, [L+][Br−] (1a), with Tl[Co(CO)4], Na[MoCp‐(CO)3], or Na[WCp(CO)3] (5a‐c) yields the corresponding ionic isophosphindolylium‐carbonylmetallates,6a‐c.Whereas1afails to react with neutral metal carbonyls, a mixture of ionic complexes of the type [LAuX+][AuYZ−] (7a, X, Y, Z = Cl or Br) is formed by reaction with two equivalents of AuCl. Treatment of AuCl with the triflate [L+][OTf−] (1b), which is accessible from1avia anion metathesis, furnishes [LAuCl+][OTf−] (7b). Both the carbonylmetallate6cand the complex7bhave been characterized by X‐ray structure analyses.7bdisplays enhanced reactivity as compared to1btowards MeOH and H2O, forming the addition products8and9a, b, the latter existing as two different diastereomers. Reactions of7bwith LiF, (Me2N)3PO, and (Et2N)2CNH), respectively, proceed via ligand exchange to yield equilibrium mixtures containing the

ISSN:0009-2940    

DOI:10.1002/cber.19951280309

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

Preparation of Phosphorus— and Fluorine‐Containing Calix[4]arene Derivatives. Conformational Analysis, Separation of the Conformers, and X‐Ray Crystal Structure Analysis of a Cone ConformerHerrn Professor Helmut Werner zum 60. Geburtstag gewidmet.The Calix[4]arene1reacts with hexamethyldisilazane or (diethylamino)trimethylsilane to form the bis‐trimethylsilyl‐ated derivative 2. Treatment of2with PF2C1 gives the mono‐and bis‐difluorophosphites3and4, which react with elimination of Me3SiF or PF3to yield the monofluorophosphite derivative5.All four OH hydrogen atoms in1are replaced by lithium on reaction withnBuLi with formation of the tetrali‐thiated product6.This has been allowed to react with the Pchlorophosphorinanones7–9.From7the cone conformer10ais formed, whereas in the case of8and9a mixture of all four possible conformars11a‐dand12a‐dis obtained. The pure conformers12a‐dare isolated. By refluxing the cone conformer12ain tetrachloroethane a conformational conversion is effected. In order to evaluate its coordinating ability,12awas allowed to react with dichloro(cycloocta‐1, 5‐diene)platinum(II) to form the trans‐disubstituted complex13.In the case of12a(acetonitrile solvate) a single‐crystal X‐ray structure analysis has been conducted. The molecule displays a cone conformation, whereby two of the opposing phenyl rings are approximately parallel and the other two approxim

ISSN:0009-2940    

DOI:10.1002/cber.19951280310

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

Water‐Soluble Phosphanes, IV. – Tertiary Alkylphosphanes with Ammonium Groups in the Side Chains — Amphiphiles with Basic P‐AtomsBy stepwise aminoalkylation of PH3with Me2N(CH2)2Cl in the superbasic medium DMSO/KOH the secondary phosphane [Me2N(CH2)2]2PH (2) is obtained in good yields. Metallation of2withn‐BuLi and subsequent reaction with Me2N(CH2)2]2Cl affords the basic tertiary phosphane [Me2N(CH2)2]2]3P (3), which on protonation with Ph3P · HBr in CH2Cl2gives {[HNMe2− (CH2)2]3P}3+3 Br−(4a) with an extremely high solubility in water. By oxidation of3with H2O2and N‐quaternisation with Me3O+BF −4the cationic phosphane oxide {[Me3N(CH2)2]3PO}3+3 BF −4(5a) is formed, which could, however, not be reduced with SiHCl3or Si2Cl6/NEt3to the corresponding tricationic phosphane. Tertiary cationic phosphanes of type [RMe2N(CH2)2P(Oct)2]+X−(8a, 8b, R = Me, C8H17; X = Br, I) are accessible by free radical addition of 1‐octene to7band7d.Addition of formaldehyde to7agives the hydroxymethyl phosphane10a.By methylation of [RMe2N(CH2)2PH2]+I−(7dand7e, R = CnH2n+1,n= 8, 12) with Mel under controlled condition and subsequent deprotonation of the phosphonium salts12band12cthe cationic tertiary phosphanes13aand13bwith l

ISSN:0009-2940    

DOI:10.1002/cber.19951280311

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY