Iridium Phosphinidene Complexes: A Comparison with Iridium Imido Complexes in Their Reaction with Isocyanides

摘要

18-Electron nucleophilic, Schrock-type phosphinidene complexes 3 [Cp~*(Xy-N=C)lr=PAr] (Ar = Mes~*, Dmp, Mes) are capable of unprecedented [1 + 2]-cycloadditions with 1 equiv of isocyanide RNCrn(Ft = Xy, Ph) to give novel iridaphosphirane complexes [Cp~*(Xy-N=C)lrPArC=NR]. Their structures were ascertained by X-ray diffraction. Density functional theory investigations on model structures revealed that the iridaphosphirane complexes are formed from the addition of the isocyanide to 16-electron species [Cp~*lr=PAr] forming first complex 3 that subsequently reacts with another isocyanide to give the products following a different pathway than its nitrogen analogue [Cp~*lr=Nt-Bu] 1.