Cyclometallation of a germylene ligand by concerted metalation–deprotonation of a methyl group

Abstract

The reaction of [CH{(CMe)(2,6-iPr₂C₆H₃N)}₂]GeCl with LiN(SiMe₃)₂ was previously reported, which led to the formation of a hetero-fulvene type germylene, [CH{(CMe)(CCH₂)(2,6-iPr₂C₆H₃N)}₂]Ge through the deprotonation of the C–H bond from the methyl substituents. In this paper, we attempted the analogous reaction with (Dipp)NCMeCHCOMeGeCl using LiN(SiMe₃)₂ which gave rise to a metathesis product, (Dipp)NCMeCHCOMeGeN(SiMe₃)₂ (2). However, the reactions of 2 with [M₂Cl₂(μ-Cl)₂(η⁵-Cp*)₂] (M = Rh and Ir) resulted in cyclometallated Rh and Ir complexes through the activation of the C–H bond from the germylene ligand. The complexes were characterized by single crystal X-ray analysis, which authenticated the presence of Ge–Rh and Ge–Ir bonds. DFT studies have been performed to understand the mechanism.