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

The tungsten hydrazido(2-) complex cis,mer-[WCl2(NNH2)(PMe2Ph)(3)], readily derived from a dinitrogen complex cis-[W(N-2)(2)(PMe2Ph)(4)], reacted with 1,3,5-triketones RCOCH2COCH2COPh (R = Me, Ph) to give the diazoalkane comp lexes cis,mer-[WCl2(NN=CRCH2COCH2COPh)(PMe2Ph)(3)] (R = Me (3), Ph) via the condensation between the hydrazido(2-) ligand and one terminal carbonyl gr oup in the triketone. By contrast, the reaction of the hydrazido(2-) comple x cis,trans-[WCl2(NNH2)(CO)(PMe2Ph)(2)] with PhCOCH2COCH2COPh resulted in t he formation of a dinuclear mu-bis(diazoalkane) complex [WCl2(CO)(PMe2Ph)(2 )(NN=CPhCH2COCH2CPh=NN)WCl2(CO)(PMe2Ph)(2)] (5). The structures of 3 and 5 in the solid state have been determined unequivocally by X-ray analysis. (C ) 1999 Elsevier Science S.A. All rights reserved.