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

Abstract

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 μ-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.