N-Heterocyclic Carbene-Phosphinidyne Transition Metal Complexes

The N-heterocyclic carbene-phosphinidene adduct IPr=PSiMe3 is introduced as a synthon for the preparation of terminal carbene-phosphinidyne transition metal complexes of the type [(IPr=P)MLn] ( MLn=(eta(6)-p-cymene) RuCl) and (eta 5-C5Me5) RhCl). Their spectroscopic and structural characteristics, namely low-field P-31 NMR chemical shifts and short metal-phosphorus bonds, show their similarity with arylphosphinidene complexes. The formally mononegative IPr=P ligand is also capable of bridging two or three metal atoms as demonstrated by the preparation of bi-and trimetallic RuAu, RhAu, Rh-2, and Rh2Au complexes.