Facile Synthesis of Phosphaamidines and Phosphaamidinates using Nitrilium Ions as an Imine Synthon

Readily accessible nitrilium triflates are convenient imine building blocks for the expedient synthesis of a novel class of 1,3-P, N ligands as demonstrated for the reaction with primary phosphanes. This procedure allows variation of all substituents. X-ray crystal structures are reported for nitrilium ions, phosphaamidines, and three phosphaamidinate complexes. The lithium phosphaamidinate is N coordinated and its reaction with [AuCl(tht)] (tht= tetrahydrothiophene) gives a unique P-bridged gold trimer, while a P, N-bidentate complex results from [{RhCl(cod)}(2)]. The nitrilium ion methodology allows extension of the 1,3-P, N motive to bis(imino)phosphanes, which are the neutral phosphorus analogues of the valuable b-diketiminate ligand.