Chromium Imidate Complexes from the Metathesis-Like Reaction of Phosphinimines and Chromium(0) Fischer Carbene Complexes

Abstract

The thermal reaction of phosphinimines with alkyl-substituted chromium(0) Fischer carbene complexes is reported. The process occurs through a metathesis-like reaction to yield stable chromium imidate complexes. The formation of the azametallacycle 15 from zwitterion 14 is the key to the process. The length of the phosphinimine tether, the electrophilicity of the imine moiety, and the bulkiness of the imine substituents determine whether the metathesis process occurs. Only those compounds having short or rigid tethers and electrophilic and moderately hindered imine groups react with electrophilic Fischer carbene complexes. Bulkier imines or less electrophilic carbene complexes are unable to form the key azametallacycles and either decompose or form the condensation products derived from acid-base reactivity.