摘要:

Bis[2,3‐naphthalenediolato(2—)](pyrrolidiniomethyl)silicate Acetonitrile Solvate: Synthesis and Crystal and Molecular Structure of a Zwitterionic λ5‐SpirosilicateThe zwitterionic spirocyclic bis[2,3‐naphthalenediolato[2–)](pyrrolidiniomethyl)silicate (3) was synthesized and the crystal and molecular structure of its acetonitrile solvate 3 · CH3CN investigated.3was prepared by reaction of trimethoxy(pyrrolidinomethyl)silane (8) or dimethoxy(methyl)(pyrrolidinomethyl)silane (8) or dimethoxy(methyl)(pyrrolidinomethyl)silane (9) with 2,3‐dihydroxynaphthalene in acetonitrile. Reaction9→3involves a remarkable Si—C cleavage with formation of CH4. The pentacoordinate silicon atom of3· CH3CN is surrounded by 4 oxygen atoms and 1 carbon atom, the latter being in an equatorial position. The coordination polyhedron can be described as a distorted trigonal bipyramid (the structure is displaced by 20.5% from the trigonal bipyramid towards the square pyramid). The crystal lattice of3·CH3CN contains centrosymmetric dimers of3, built up by intermolecular N

ISSN:0009-2940    

DOI:10.1002/cber.19911240702

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Synthesis, Structure, and Complexation of 2,2′,5,5′‐Tetrahydro‐1,1′‐Bi(1H‐1,2,5‐phosphadiborole) DerivativesReactions of (Z)‐1,2‐diborylethenes [HC — B(Cl)R]2with LiPH2and LiP(SiMe3)2lead to the 2,5‐dihydro‐1H‐1,2,5‐phosphadiboroles1a—din good yields.1a,breact with (Me3C)2Hg to give yellow2a(56%) and2b(90%), which are also obtained from1c,dand TlCl or C2Cl6, respectively. The constitution of2bis established by an X‐ray structure analysis.2areacts with Cr(CO)3(CH3CN)3to yield the bis(pentacarbonyl)chromium complex4a, whereas2band Fe(CO)3(C8H14)2form the bis(tricarbonyliron) compex5b. Spectroscopic studies and X‐ray structure analyses of4aand5bshow that in4athe chromium atom is η1‐bound to phosphorus, whereas in5bthe iron interacts w

ISSN:0009-2940    

DOI:10.1002/cber.19911240703

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Complexation of 1,3‐Dihydro‐1,3‐diborapentafulvene Derivatives with Fe(CO)3Fragments: Syntheses, Crystal and Electronic Structure of μ‐(η4: η5‐1,3‐Dihydro‐1,3‐diborapentafulvene)‐bis(tricarbonyliron) ComplexesReactions of the 1,3‐diborapentafulvene derivatives1a–cwith (CO)3Fe(C8H14)2lead to the violet dinuclear complexes3a–c, which possess a slipped triple‐decker structure. The X‐ray structure analyses of3b,creveal that one Fe(CO)3group is pentahapto‐coordinated to the 1,3‐diborole frame of C2B2C=C, whereas the other interacts with the Y‐shaped B2C=C unit. The latter resembles the interaction of Fe(CO)3with trimethylenemethane. An MO calculation indicates that the formation of3occurs by distortion of1· Fe(CO)3; the slippage of Fe(CO)3from η5to η4bonding is followed by η

ISSN:0009-2940    

DOI:10.1002/cber.19911240704

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Synthesis and Crystal Structure of Li2[(Me3SiCH2)3AlCH2Al(CH2SiMe3)3]—a Dilithiomethane Derivative?Reaction of (trimethylsilyl)methyllithium with the methylene‐bridged aluminium tetrachloride Cl2AlCH2AlCl2yields dilithium methylenebis[tris(trimethylsilylmethyl)aluminate] (2) as the only isolable product. All attempts for preparing the tetraalkyl analogue have been unsuccessful. The crystal structure of2exhibits a hexacoordinated central carbon atom with short LiC distances. Both lithium atoms and the methylene hydrogens of the AlCH2 Al unit are almost coplanar. The discussion of the structure and properties leads to the attractive description of2as an adduct of tris(trimethylsilylmethyl)‐aluminium to dil

ISSN:0009-2940    

DOI:10.1002/cber.19911240705

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Chemistry of Cyanogen: Reactions of Diiminosuccinonitrile (DISN) with Sulfenyl Chlorides, Chlorotrimethylsilane and Ring Closure to Trifluoromethyl‐Substituted 2H‐Imidazoles4,5‐Dicyano‐2‐hydroxy‐2‐(trifluoromethyl)‐2H‐imidazole (1) is easily prepared by treating DISN with trifluoroacetic anhydride. In the presence of 4‐(dimethylamino)pyridine, however, theO‐acylated derivative2is formed in excellent yield, while the reaction of1with chlorotrimethylsilane affords theO‐silylated product6. A bi‐1,2,5‐thiadiazole of the formula S2(CN)4Cl2(5) is the final reaction product, when DISN is treated with sulfur dichloride in the presence of “naked” chloride ions. On the other hand the non‐heterocyclicN‐sulfenyl derivative4has readily been obtained, when DISN is treated with F3CSCl instead. Finally a procedure is described to convert DISN into th

ISSN:0009-2940    

DOI:10.1002/cber.19911240706

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Synthesis and Structures of Imidotitanium Compounds — Directing the Monomer‐Dimer Formation by Changing the Basicity of the SolventsThe reaction of (i‐Pr)2PN(SiMe3)2(1) with elemental sulfur leads to (i‐Pr)2P(S)N(SiMe3)2(2). Compound2reacts with TiCl4with elimination of chlorotrimethylsilane to yield the adducts [(i‐Pr)2P(S)NTiCl2‐MeCN]2(3) and (i‐Pr)2P(S)N = TiCl2.3py (4), crystallized from MeCN or pyridine, respectively. Compound3crystallises in the space groupPbca,4in the space

ISSN:0009-2940    

DOI:10.1002/cber.19911240707

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Syntheses, NMR spectra, and X‐ray molecular structures of three (2‐hetero‐)1,3‐diphosphabenzenes are reported which constitute an isoelectronic triade of compounds with BH2, CH, and N bridging units between the two phosphorus atoms. The remaining three carbon atoms of the rings are part of a 2‐methallylic system. The 2‐borataheterocycle3has been prepared by the reaction of CH2= C(CH2)PPh2)2(1) with Me2SBH2Br to give an intermediate2still containing the exocyclic olefinic bond. Treatment of2with a base, deprotonation of one ring CH2group, and proton migration from the other one to the olefinic CH2group afford the 5‐methyl‐1λ5‐phospha‐3‐phosphonia‐2‐boratabenzene3. The PBP unit is tilted by 144.0(2)° against the planar C3P2part of the ring. A heterocyclic precursor4for the carbon analog is generated from1and CH2I2, which on reaction with a strong base yields the diphosphabenzene5with a fully planar ring skeleton. For the synthesis of the aza analog7, CH2=C(CH2Cl)2is treated with HN(PPh2)2to give the precursor6, which can be deprotonatad at nitrogen and carbon with a base. In the crystals of7, two independent molecules of very similar structure are present. The molec

ISSN:0009-2940    

DOI:10.1002/cber.19911240708

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

The tetrahydro‐4,4,8,8‐tetramethyl‐4,8‐disila‐s‐indacenyl anion (LH) reacts with or without cyclopentadienyl anion (Cp−) and Fe2Cl4(THF)3to give the mixed ferrocenes CpFe(LH) and (LH)2Fe in 50 and 63% yield, respectively. Near room temperature and in solution CpFe(LH) exists as a pair of enantiomers (syn‐3a/b). According to an X‐ray analysis both enantiomers are present in a single crystal. Compound3consists of a ferrocene linked to a cyclopentadiene by two Me2Si groups such that the acidic Cp proton points towards the iron. Temperature‐dependent NMR spectra show thatsyn‐3aandsyn‐3bare non‐rigid molecules which are interconverted by 1,2‐silatropic bond shifts (Ea= 49.2 ± 2.9 kJmol‐1). Three more isomers (anti‐3a,anti‐3b, and the spiro derivative3c), though present only in low concentration, are engaged in the rearrangement. (LH)2Fe is also non‐rigid and exists as a pair of diastereomers (4aand4b). The isomers of3and4undergo hydrolysis (e.g., syn‐3a/3bgives [(Me2SiOSiMe2)Cp]FeCp (5) among others) and deprotonation. The latter yields CpFe(L–) (7) and (L−)2Fe (8), which are characterized by NMR spectroscopy.7forms crystals with [Li(TMEDA)]+as counterion, and an X‐ray analysis shows that lithium and iron are located at opposite sides of the strongly folded ligand L. The reaction of7with CrCl2(THF) gives the trinuclear stacked metallocene9in 47% yield.9has two unpaired electrons which are locat

ISSN:0009-2940    

DOI:10.1002/cber.19911240709

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Metal Complexes of Biologically Important Ligands, LX. — Metal Complexes of 3′‐Azido‐3′‐deoxythymidine (AZT) and 3′‐Isocyano‐3′‐deoxythymidineMetal complexes of N‐3‐deprotonated 3′‐azido‐3′‐deoxythymidine (AZT — H+), (AZT — H+)AuPR3(R = Me, Et, Ph) (2,3,4),trans‐(AZT — H+)2Pd(NH3)2(5), [(n‐Bu3P)(AZT — H+) M(μ‐Cl)2M(AZT — H+)(n‐Bu3P)] (M = Pd, Pt) (6,7),trans‐(Ph3P)2Pd(AZT — H+)2(8),cis‐(Ph3P)2Pt(AZT— H+)(Cl) (9), and complexes of 3′‐isocyano‐3′‐deoxythymidine (L), (Et3P)(L)‐ PdCl, (11),(12), (n‐Bu3P)(L)PtCl2(13), [(Ph3P)2(L)PtCl](BF4) (14), (η5‐C5Me5)(L)RhCl2(15), and (η5‐C5Me5)(L)IrCl2(16) have been prepared and characterized by IR and NMR spectra,2by X‐ray crystallography.2,4, a

ISSN:0009-2940    

DOI:10.1002/cber.19911240710

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

Conversion of the Clusters Fe3(CO)9(μ3‐η2‐N2Et2and Fe3(CO)9(μ3‐NEt)2into Organic ProductsThe azoalkane‐bridged cluster Fe3(CO)9(μ3‐η2‐N2Et2)(1) and its thermal rearrangement product Fe3(CO)9(μ3‐NEt)2(2) are converted by standard routes into derivatives with one carbene ligand C(Ph)OEt (3,4). Degradation (thermally or oxidatively) of these compounds produces the diaziridine(5) and/or the iminoester EtN = C(Ph)OEt (6).4and moistp‐tolyl isocyanide form the indole derivative8.1adds one or two equiv. of alkynes leading to the alkyne‐bridged cluster9or the ferrole‐type clusters10. The clusters10, resulting from HCCPh, exist as two isomers10aandbwhich can be equilibrated and separated. An alternative route to10 c(alkyne: MeCCMe) starts from Fe2(CO)6(C4Me4) by treating it with Fe2(CO)9and N2Et2. Photolytic or oxidative degradation of the clusters10produces substituted furan13, pyrrole14, or dihydropyridazine15. The crystal structures of the clusters4,9,10

ISSN:0009-2940    

DOI:10.1002/cber.19911240711

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY