Coordination complexes of TiX4 (X = F, Cl) with a bulky N-heterocyclic carbene: Syntheses, characterization and molecular structures

Abstract

Reactions of the sterically encumbered N-heterocyclic carbene IPr (IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene, [:C{[N(2,6-iPr2C6H3)]CH}2]) (1) with TiX4 (X=Cl, F) in diethyl ether or THF afford the metal halide mono- and bis-carbene complexes, [Cl4Ti-C{N(2,6-iPr2C6H3)CH}2] (2), [Cl4Ti{C{N(2,6-iPr2C6H3)CH}2}2] (3) and [F4Ti{C{N(2,6-iPr2C6H3)CH}2}2] (4). Compounds 2–4 have been completely characterized by elemental analysis, NMR spectroscopic methods (1H, 13C and 19F NMR) and single crystal X-ray structure determination. Furthermore, the reaction of [Cl4Ti-C{N(2,6-iPr2C6H3)CH}2] (2) with ZnMe2 yields monomeric [ZnCl2·IPr] (5), involving the transfer of carbene and chlorido ligands from Ti (IV) to Zn(II).