Oxygen insertion reactions of mixed N-heterocyclic carbene–oxazolinylborato zinc alkyl complexes

摘要

We report the synthesis of a new mixed oxazoline–carbene scorpionate ligand, bis(4,4-dimethyl-2-oxazolinyl)(1-mesitylimidazolyl)phenylborate (PhB(Ox~(Me2))_2Im~(Mes)). Reactions of the protonated form PhB(Ox~(Me2))_2(Im~(Mes)H) with dialkylzinc compounds provide four-coordinate zinc alkyl complexes, and X-ray diffraction studies of the {PhB(Ox~(Me2))_2Im~(Mes)}ZnR (R = Me, Et) compounds show significant structural distortions involving the R groups shifting away from the carbene donor. The reaction of {PhB(Ox~(Me2))_2Im~(Mes)}ZnEt (3) and O_2 provides an isolable mononuclear zinc alkylperoxide {PhB(Ox~(Me2))_2Im~(Mes)}ZnOOEt (4), which has been characterized by single crystal X-ray diffraction and ~(17)O NMR spectroscopy.