Dialkylgallium Complexes with Alkoxide and Aryloxide Ligands Possessing N-Heterocyclic Carbene Functionalities: Synthesis and Structure

Abstract

Methods for the synthesis of dialkylgalium compounds with alkoxide or aryloxide ligands possessing N-heterocyclic carbene functionalities have been established. As a result, the synthesis of a series of dialkylgallium complexes Me2Ga(O,C) (1, 3–5), and Me2Ga(O,C)·Me3Ga (2, 6) is described, where (O,C) represents an alkoxide or aryloxide monoanionic chelate ligand with an N-heterocyclic carbene functionality. All complexes have been fully characterized using spectroscopic and X-ray techniques. The presence of a strongly basic NHC functionality in alkoxide or aryloxide ligands resulted in the formation of monomeric Me2Ga(O,C) species. The reaction of those complexes with the Lewis acid Me3Ga leads to Me2Ga(O,C)·Me3Ga adducts (2 and 6) with a strong Me3Ga–O dative bond. The effect of (O,C) ligands with various steric and electronic properties on the structure of obtained Me2Ga(O,C) and Me2Ga(O,C)·Me3Ga has been discussed on the basis of spectroscopic data. Finally, the bond valence vector model has been used...