Diazoalkane Complexes of Molybdenum and Tungsten

Article abstract of DOI:10.1021/ja00370a015

Ordinary diazoalkanes, N2CHR' and N2C(CH3)R' (R' = C6H5, p-CH3C6H4), were found to react with M(CO)3(S2CNR2)2 (M = Mo, W; R = CH3, C2H5; R2 = (CH2)4) at room temperature to form stable complexes of the type M(CO)(N2CHR')(S2CNR2)2 which were conveniently isolated in good yields.Oxidaion of M(CO)(N2CHR')(S2CNR2)2 with 1 equiv of Cl2 or Br2 produced MX2(N2CHR')(S2CNR2)2 (X = Cl, Br) which were isolated as chloroform solvates.The addition of excess HBr to W(CO)(N2CHR')(S2CNMe2)2 gave a red solid which analyzed for WBr2(N2H2CHR')(S2CNMe2)2.Physical and spectroscopic data suggest that the diazoalkane ligands in the above complexes behave as terminal, singly bent, four-electron donor ligands.The NMR chemical shifts of the methine proton in N2CHR' ligands indicate that the M(S2CNR2)2 unit is strogly electron withdrawing.Syntheses for new tungsten compounds, W(CO)3(S2CNR2)2, W(CO)2(S2CNR2)2, W(CO)2(L)(S2CNR2)2 (L = p-CH3C6H4NHNH2, 4-CH3C5H4N), WBr2(S2CNR2)2, W(S2CNR2)4, and WBr3(S2CNR2)2, are also reported.