Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)6]-, [Ta(CNXyl)6]-, and Derivatives Thereof1
文摘
Treatment of [M(CO)6]-, M = Nb, Ta, with Ag+, I2 or NO+ in the presence of CNXyl provided[M(CNXyl)7]+, M(CNXyl)6I, or cis-[M(CNXyl)4(NO)2]+, which are isocyanide analogues of the unknowncarbonyl complexes [M(CO)7]+, M(CO)6I, or cis-[M(CO)4(NO)2]+, respectively. Reduction of M(CNXyl)6I bycesium graphite gave the respective Cs[M(CNXyl)6], which have been structurally characterized andrepresent the first isolable homoleptic isocyanidemetalates for second or third row transition metals.Nitrosylation of [Ta(CNXyl)6]- affords a rare example of a mononitrosyl tantalum complex, Ta(CNXyl)5NO,which is an isocyanide analogue of the unknown Ta(CO)5NO. This study emphasizes, inter alia, theremarkable versatility of the CNXyl ligand compared to CO in stabilizing various electronic environmentsat heavier group 5 metal centers.