Bioctahedral Complexes Research Articles

Oxidative addition to M-M quadruple bonds. Preparation of new edge-sharing bioctahedral complexes of the type (L-L)Cl2M(.mu.-Cl)2MCl2(L-L) (M = molybdenum, tungsten, L-L = 1,2-bis(diphenylphosphino)ethane; M = Mo, L-L = 1-(diethylphosphino)-2-(diphenylphosphino)ethane)

Oxidative addition to M-M quadruple bonds. Preparation of new edge-sharing bioctahedral complexes of the type (L-L)Cl2M(.mu.-Cl)2MCl2(L-L) (M = molybdenum, tungsten, L-L = 1,2-bis(diphenylphosphino)ethane; M = Mo, L-L = 1-(diethylphosphino)-2-(diphenylphosphino)ethane)

The structures of metal-metal-bonded edge-sharing bioctahedral complexes

The structures of metal-metal-bonded edge-sharing bioctahedral complexes

Vanadium(II) and niobium(III) edge-sharing bioctahedral complexes that contain bis(dimethylphosphino)methane bridges

Preparation et caracterisation par diffraction RX des complexes [VCl(dmpm)BH 4 ] 2 et Nb 2 Cl 6 (dmpm) 2

Studies of confacial bioctahedral tungsten complexes containing metal-to-metal bonds: synthesis, reactions, and nuclear magnetic resonance studies of W2Cl4(μ-SR)2(μ-S)L2 (R = alkyl; L = monodentate ligand)

A series of new binuclear tungsten(IV) complexes, W2Cl4(μ-SR)2(μ-S)L2 (R = Me, Et, iBu, CH2Ph; L = Me2S or THT), is readily synthesized from the metathetical reaction of WCl4L2 with 1 mol-equiv. of alkylthiotrimethylsilane (Me3Si(SR)). These complexes react with stronger nucleophiles (Ph3P, MeCN, C5H5N, Cl−) under ambient conditions to yield simple disubstituted products. Reaction of W2Cl4(μ-SEt)2(μ-S)(SMe2)2 with PhCH2X (X = Cl, Br) yields [Me2SCH2Ph]2[W2Cl4(μ-SEt)2(μ-S)X2], whilst with stronger alkylating agents, MeSO3F or Et3OBF4, intractable residues result.The series of homologous complexes has been studied by 1H and 13C nmr spectroscopy. When R = Me, two stable configurational isomers are present in solution, whilst only a single isomer exists for more bulky R groups. Trends in the 1H nmr chemical shifts of the methylene and methyl protons of the SEt groups in the complexes W2Cl4(μ-SEt)2(μ-S)L2 allow absolute assignment of the resonances to two magnetically inequivalent thiolato groups.

Metal-metal-bonded complexes of the early transition metals. 4. Synthesis and characterization of the tantalum(III) dimer Ta2Cl6(PMe3)4

The dimeric tantalum(III) phosphine complex Ta/sub 2/Cl/sub 6/(PMe/sub 3/)/sub 4/ (1) has been prepared from the reaction of tantalum pentachloride, trimethylphosphine, and sodium amalgam in toluene. The compound crystallizes in the noncentrosymmetric orthorhombic space group P2/sub 1/2/sub 1/2/sub 1/ with a = 11,681 (3) angstroms, b = 11.834 (3) angstroms, C = 20.257 (7) angstroms, V = 2800.18 angstroms/sup 3/, and rho(calcd) = 2.085 g cm/sup -3/ for mol wt 878.9 and Z = 4. The structure refined to R/sub F/ = 0.037 and R/sub wF/ = 0.035. 1 is a distorted edge-sharing bioctahedral complex with axial phosphines on one tantalum and equatorial phosphines on the second. Direct P-P coupling is observed across the dimer with J/sub PP'/ = 2.46 Hz. The metal-metal bond length in 1 is 2.721 (1) angstroms, and the formal metal-metal bond order in this d/sup 2/-d/sup 2/ dimer is 2.