摘要:

AbstractTreatment ofcis,cis‐1,3,5‐tris[(diphenylphosphanyl)methyl]‐cyclohexane (tdppmcy) (1) with Ir(PPh3)2(CO)Cl in toluene gives the trinuclear complex [Ir(CO)Cl]3(tdppmcy)2(2) in high yield. In this complex the tripodal molecule tdppmcy behaves as a trismonodentate ligand since each phosphorus atom is bound to one metal center. Compound2can be transformed into the trinuclear complexes {[Ir(CO)‐(Cl)H]3(tdppmcy)2)3+(3), [Ir(CO)(Cl)H2]3(tdppmcy)2(4), and [Ir(CO)H3]3(tdppmcy)2(5) by treatment with H+, H2, and H−, respectively. The chemistry of 2 supports the spectroscopic findings of a square‐planar environment at the metal c

ISSN:0009-2940    

DOI:10.1002/cber.19951280202

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe BB bond of tri‐tert‐butylazadiboriridine [NRBRBR] (R =tBu;1) is oxidized by MeOH to give the (hydroboryl)(methoxyboryl)amine HBRNR‐BR(OMe) (2a). μ‐2,3‐Hydroazoniadiborata‐1‐cyclopropenes [NRBR(X)μHBR] (3a, 3c‐e) are formed by the action of the acids HX upon1. A similar hydrogen bridge as in3a‐eis formed during the hydroboration of1by catecholborane, yielding3f. A B atom is identified in the products3a‐fto be planarly coordinated by four atoms, two of which are forming a BHB three‐center bond with that B atom. This is a novel bonding situation in boron chemistry. The structures of the products are deduced from1H‐,11B‐, and13C‐NMR spectra and are c

ISSN:0009-2940    

DOI:10.1002/cber.19951280203

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractDeprotonation of NH protons, of four diorgano‐, organo(trimethylsilyl)‐ and bis(trimethylsilyl)hydrazines byn‐butyllithium in hexane led to the following lithium hydrazides: [Et‐(Li)N‐N(H)Et]6, (1)6, [Me3Si(Li)N‐N(Li)SiMe3]4, (2)4, [Me3Si‐(Li)N‐N(Li)SiMe3· (Me3Si)2N‐N(Li)SiMe3]2(3)2, and [Ph‐(Li)N‐N(Li)SiMe3]4, (4)4, respectively. The structure determination by X‐ray methods at low temperature reveals butterfly‐shaped Li2N2structural monomeric units which associate through “laddering” to the observed oligomers thereby generating penta‐ and hexacoordinated Li centers. N‐N bonds lengths of up to 1.556 Å suggest that negative charge accumulates at the nitrogen atoms of (1)6, (2)4, and (3)2. An amazing structure shows the red compound4where two Li ions are π‐sandwiched between two phenyl groups each. The compound can be looked at as a new type of a lithium lithiate complex, Li2[Li6N8Ph4(SiMe3)4], but short N‐C and N‐N bonds in the Li6N8core indicate that its negative

ISSN:0009-2940    

DOI:10.1002/cber.19951280204

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

Synthesis and Structure of Dinuclear Copper(II) Complexes of a Novel Hexaaza Macrocycle Containing Bridging Oxalate and Acetate IonsNon‐template Schiff base [2 + 2] condensation of pyridine‐2,6‐dicarbaldehyde with 1,4‐diamino‐2‐butyne yields the hexaazamacrocyclic ligand1, which is converted to2by NaBH4reduction of the imino groups. Two dinuclear copper(II) complexes of2containing oxalate and acetate ions, [(2)Cu2(μ‐C2O4)](BPh4)2(3) and [(2)Cu2(μ‐CH3CO2)(OH2)](PF6) 2.25 −(NO3)0.75(4), were characterized by X‐ray crystallography. The oxalate ligand in3forms a (μ‐η4:η4) bridge between the copper atoms. Compound4contains asyn‐anti‐bridging acetate ion. The Cu‐Cu distances are 5.315 Å in3and 4.746 Å in4, respectively. Oxalate can be separated from other carboxylates in aqueous solution by selective binding to t

ISSN:0009-2940    

DOI:10.1002/cber.19951280205

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe complex [(acac)AuCH(PPh2AuPPh2)2CHAu(acac)] (1) is obtained by various procedures: a) by reaction of [Ph3PAuCH (PPh2AuPPh2)2CHAuPPh3](ClO4)2with NBu4[Au(acac)Cl], b) by reaction of [ClAuCH(PPh2AuPPh2)2CHAuCl] with [Au(acac)PPh3] or with Tl(acac) and c) by reaction of [ClAuPPh2CH2PPh2AuCl] with Tl(acac). The acetylacetonato ligand can act as deprotonating agent; thus, complex1reacts with (phosphane)gold complexes, [Au(C6F5)2{(PPh2)2‐CH2)]ClO4, [Au(C6F5)3(PPh2CH2PPh2)] or [Au(PPh3)2]ClO4, to give the hexanuclear complexes [(C6F5)2Au{(PPh2)2CH} AuCH(PPh2AuPPh2)2CHAu{CH(PPh2)2) Au(C6F5)2](ClO4)2, [(C6F5)3Au(PPh2CHPPh2)AuCH (PPh2AuPPh2)2CHAu‐(PPh2CHPPh2)Au(C6F5)3] or [(Ph3PAu)2C(PPh2AuPPh2)2C‐(AuPPh3)2](ClO4)2, respectively. The crystal structure of1has been established by X‐ray crystallography and displays two independent eight‐membered rings with inversion symmetry and short transannular gold‐gold contacts. The first ab initio results for a transannular AuI‐AuIinteraction

ISSN:0009-2940    

DOI:10.1002/cber.19951280206

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe tridentate N,O,S‐ligand (RS)‐2‐[(2‐mercapto‐1‐methylamino)ethyl]phenol (rac‐1) was prepared fromortho‐hydroxy‐chloroacetophenone in three steps. When this ligand was treated with nickel(II) acetate, the novel “Ni3S4N3” clusterrac‐3was obtained. The X‐ray crystal structure ofrac‐3unambiguously revealed thepseudo‐C3symmetric structure of this novel nickel cluster, which is made up by three nickel ions, one sulfide sulfur atom, and threehomochiralligand molecules, each contributing one thiolate sulfur atom and one amine nitrogen atom to the ligation of the metal ions. According to NMR‐spectroscopic results, this highly symmetric structure is maintained in solution. The magnetic studies revealed diamagnetic behavior in the solid state, although antiferromagnetic interaction of the metal center

ISSN:0009-2940    

DOI:10.1002/cber.19951280207

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractCycloalkylated biimidazolium dications (A2+) of reduction potentials from ‐0.4 to ‐1.4 V form ion pair charge‐transfer complexes {A2+[M(mnt)2]2−} with dithiolene metalates, M = Zn, Ni, Pd, Pt, mnt2−= maleonitrile‐2,3‐dithiolate. X‐ray analyses of {P2BBIm2+[Ni(mnt)2]2−} [P2BBIm2+= 1,1′,3,3′‐bis(propane‐1,3‐diyl)bibenzimidazolium] and {B2Blm2+[Pd(mnt)2]2−} [B2BIm2+= 1,1′,3,3′‐bis(butane‐1,4‐diyl)biimidazolium] reveal that the solid‐state structure is largely determined by the geometry of the acceptor. When the latter is strongly twisted, the usually observed mixed donor‐acceptor columns are modified to a chain‐like arrangement. In the case of the bibenzimidazolium dication P2BBIm2+the otherwise planar [Ni(mnt)2]2−becomes tetrahedrally distorted. By the application of the Hush model a reorganization energy of about 67 kJ/mol is estimated for the thermal electron transfer from [M(mnt)2]2−to A2+when M = Ni, Pd, Pt, but considerable deviations from this model are observed when M = Zn. Irradiation of the free biimidazolium acceptors in the presence of EDTA affords the strongly reducing radical cations which reduce water to hydrogen in the presence of colloidal platinum. Attempts to sensitize this reaction by irradiating into the charge‐transfer band of {A2+[M(mnt)2]2−} have failed until now. The molar absorptivity of one biimidazolium

ISSN:0009-2940    

DOI:10.1002/cber.19951280208

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe reactions of organolithium compounds of the type (R3Si)2CHLi (R3= Me3or Me2Ph) with the gold(I) complex Ph3PAuCl afford the monoaurated bis(silyl)methanes (R3Si)2‐CHAuPPh3(1a, b) in high yield. These compounds are converted into complex salts with hypercoordinate methanium cations {(R3Si)2C[Au(PPh3)]3}+BF−4(3a, b) by treatment with {[(Ph3P)Au]3O}+BF−4. In the reaction mixtures small amounts of the neutral dinuclear intermediates {(R3Si)2C[Au(PPh3)]2} (2a, b) have been detected and characterized by their spectroscopic data. Compounds1a, band3a, bhave been studied by single crystal X‐ray diffraction analyses. While the mononuclear molecules1a, bhave conventional structures with parameters representing classical types of bonding, the novel trinuclear complexes3a, bfeature cations with a pentacoordinate carbon atom in a distorted trigonal‐bipyramidal environment of two silicon atoms and one gold atom in equatorial positions and the remaining two gold atoms at the axial vertices of the polyhedra. The main axis of the bipyramid is strongly bent at the central carbon atoms. This distortion leads to short axial/equatorial Au…Au distances indicating peripheral metal‐

ISSN:0009-2940    

DOI:10.1002/cber.19951280209

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractTris(trimethylsilyl)silylmagnesium bromide, obtained in situ from tris(trimethylsilyl)silyllithium and magnesium bromide, reacts with acetone, pivalaldehyde, or 2,4,6‐trimethylbenzaldehyde to give the (1‐hydroxyalkyl)tris(trimethylsilyl)silanes (Me3Si)3SiC(OH)Me2(1a), (Me3Si)3CH(OH)tBu (1b), and (Me3Si)3SiC(OH)Mes (1c), resp. After deprotonation with methyllithium in ether at ‐78°C1a‐celiminate trimethylsilanolate according to a modified Peterson mechanism to form transient silenes (Me3Si)2Si=CR1R2(6a: R1= R2= Me;6b: R1= H, R2=tBu;6c: R1= H, R2= Mes). In the absence of trapping agents these silenes dimerize,6aleading to the linear dimer 1‐isopropenyl‐2‐isopropyl‐1,1,2,2‐tetrakis(trimethylsilyl)disilane (7) and6bgiving the head‐to‐head cyclodimerization product (E)‐3,4‐di‐tert‐butyl‐1,1,2,2‐tetrakis(trimethylsilyl)‐1,2‐disilacyclobutane (8), whereas6cin a very unusual cyclodimerization step affords (E)‐1,2,3,8a‐tetrahydro‐1‐mesityl‐5,7,8a‐trimethyl‐2,2,3,3‐tetrakis(trimethylsilyl)‐2,3‐disilanaphthalene (9). Compound9is the result of an unexpected [2 + 4] reaction, in which the silene formally acts as the monoene and – involving the aromatic substituent – simultaneously also as the diene. The reaction of1a‐cwith methyllithium in THF at low temperature initiates 1,3‐Si,O‐trimethylsilyl migrations leading to (trimethylsiloxy)‐[bis(trimethylsilyl)silyl]alkanes (Me3Si)2SiH–CR1R2OSiMe33a‐c.Reaction of1a‐cwith an excess of methyllithium,tert‐butyllithium, or phenyllithium, leads to trisilanes (Me3Si)2‐SiR3–CHR1R211a‐e, formed by the addition of the organolithium reagent to the Si=C bond of the transient silences6a‐c.Deprotonation of1band1cin the presence of 2,3‐dimethyl‐1,3‐butadiene gives the [2 + 4] cycloadducts 6‐tert‐butyl‐3,4‐dimethyl‐1,1‐bis(trimethylsilyl)‐1‐sila‐3‐cyclohexene (12a) and 6‐mesityl‐

ISSN:0009-2940    

DOI:10.1002/cber.19951280210

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractTreatment offac‐[(P2SPh‐P,P')Mn(CO)3Br] andfac‐[(PS2Ph‐P,S)Mn(CO)3Br] [P2SPh: Z = PPh2;PS2Ph: Z = SPh in CH3C‐(CH2PPh2)(CH2SPh)(CH2Z)] with silver hexafluorophosphate yields the η3‐tripodal manganese complexes [(P2SPh‐P,P',S)Mn(CO)3]PF6(7) and [(PS2Ph‐P,S,S')Mn(CO)3]PF6(9), respectively, whereas the reaction of CH3C(CH2PPh2)2‐(CH2SH) with Mn(CO)5Br gives directly [CH3C(Ph2‐PCH2)2(CH2S)‐P,P',S]Mn(CO)3(11). Both ionic complexes7and9undergo stereospecifically ligand substitution upon treatment with Br−, I−, N−3, SCN−and CN−to givesyn‐fac‐[(P2SPh‐P,P')Mn(CO)3X] andsyn‐fac‐[(PS2Ph‐P,S)Mn(CO)3X] (X = Br, I, SCN, N3, CN) respectively, but the neutral complex11fails to undergo such a substitution reaction with these ions. However, reaction of I−with the complex [(PSMe)‐P,P',S]Mn(CO)3]BF4(20) [P2SMe= CH3C(CH2‐PPh2)2(CH2SCH3)), which is obtained from theS‐alkylation of11with (CH3)3OBF4, affordssyn‐fac‐[(P2SMe)‐P,P']Mn(CO)3I (22s) exclusively. The possible r

ISSN:0009-2940    

DOI:10.1002/cber.19951280211

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY