Condensation of triketones with tungsten hydrazido(2-) complexes derived from a dinitrogen complex: formation of mononuclear or dinuclear diazoalkane complexes

摘要

The tungsten hydrazido(2-) complex cis,mer-[WCl_2(NNH_2)(PMe_2Ph)_3], readily derived from a dinitrogen complex cis-[W(N_2)_2(PMe_2Ph)_4], reacted with 1,3,5-triketones RCOCH_2COCH_2COPh (R = Me, Ph) to give the diazoalkane complexes cis,mer-[WCl_2(NN=CRCH_2COCH_2COPh)(PMe_2Ph)_3] (R = Me (3), Ph) via the condensation between the hydrazido(2-) ligand and one terminal carbonyl group in the triketone. By contrast, the reaction of the hydrazido(2-) complex cis,trans-[WCl_2(NNH_2)(CO)(PMe_2Ph)_2] with PhCOCH_2COCH_2COPh resulted in the formation of a dinuclear #mu#-bis(diazoalkane) complex [WCl_2(CO)(PMe_2Ph)_2(NN=CPhCH_2COCH_2CPh=NN)WCl_2(CO)(PMe_2Ph)_2] (5). The structures of 3 and 5 in the solid state have been determined unequivocally by X-ray analysis.