Dialkylgallium Complexes with Alkoxide and AryloxideLigands Possessing N-Heterocyclic Carbene Functionalities:Synthesis and Structure.

Methods for the synthesisof dialkylgalium compounds with alkoxideor aryloxide ligands possessing N-heterocyclic carbene functionalitieshave been established. As a result, the synthesis of a series of dialkylgalliumcomplexes Me2Ga(O,C) (1, 3–5), and Me2Ga(O,C)·Me3Ga (2, 6) is described, where (O,C) represents analkoxide or aryloxide monoanionic chelate ligand with an N-heterocycliccarbene functionality. All complexes have been fully characterizedusing spectroscopic and X-ray techniques. The presence of a stronglybasic NHC functionality in alkoxide or aryloxide ligands resultedin the formation of monomeric Me2Ga(O,C) species. The reactionof those complexes with the Lewis acid Me3Ga leads to Me2Ga(O,C)·Me3Ga adducts (2and 6) with a strong Me3Ga–O dative bond. Theeffect of (O,C) ligands with various steric and electronic propertieson the structure of obtained Me2Ga(O,C) and Me2Ga(O,C)·Me3Ga has been discussed on the basis ofspectroscopic data. Finally, the bond valence vector model has beenused to estimate the effect of a chelating (O,C) ligand on strainsin complexes 1–6on the basis ofX-ray data. [ABSTRACT FROM AUTHOR]