Reactions of W2(H)(OR)7, W2(OR)6(py)2 and W4(OCH2cC4H7)12 compounds (R = Pri, CH2But, cC5H9) with azobenzene, 1,2-diphenylhydrazine and 1,1-dimethylhydrazine

Abstract The reaction of W 2 (H)(OR) 7 , W 2 (OR) 6 (py) 2 and W 4 (OCH 2 c C 4 H 7 ) 12 compounds ( R = Pr i , CH 2 Bu t , c C 5 H 9 ) in hydrocarbon solvents with azobenzene, 1,2-diphenylhydrazine and 1,1-dimethylhydrazine have been studied. The tetranuclear cluster proved to be inert while W 2 (H)(OR) 7 was the most kinetically labile. In all cases where a reaction was observed the dinuclear center was ultimately oxidized with the formation of imido (NR 2− ) or hydrazido (NNR 2 2− ) ligands being formed. These were isolated as compounds of W(6+) supported by four OR ligands. These products require alkoxide group scrambling and no compound from which OR groups were lost was detected. Studies of the reactions between W 2 (H)(OR) 7 compounds and hydrazines by low-temperature NMR spectroscopy indicate the initial formation of 1:1 adducts followed by elimination of H 2 and ROH as the hydrazine is activated. The following compounds were isolated and crystallographically characterized by single crystal studies: [W(OPr i ) 4 NPh] 2 , [W 3 (μ 3 -H)(OPr i ) 9 (NPh (py)], [W(Opr i ) 4 (NpH)(pyl)] and [W(OPr i ) 4 (NNMe 2 )((py)]. The trinuclear tungsten compound is noteworthy in being a rare, if not the only, example of a 12-electron triangular metal cluster capped by a hydrido ligand. In the other structures the W(6+) center is in a distorted octahedral coordination and the imido or hydrazido(2−) ligand is terminal with significant contribution from the resonance form having a W-N triple bond.