NHC-Induced Dismutation of Gallium–Zinc Bonds

The insertion of gallium (I) reagent (BDI) GaI (I, BDI = HCC (CH3) Ndipp2; dipp = 2, 6-di-isopropyl-phenyl) into ZnII–X bonds (X = OTf, Cl) to provide gallyl zinc complexes (BDI) Ga (X) Zn (X) L2 (1 – 3; L2 = thf2, tmeda; tmeda = N, N, N′, N′-tetramethylethylenediamine) is readily reversed by ligand substitution with an N-heterocyclic carbene (NHC), regenerating I and eliminating (NHC) nZnX2 via ‘dismutation’ of the Ga–Zn bond. The dative Ga→Zn interaction present in (BDI) Ga·Zn (Cl) (tmeda) BArF4 (4; ArF = C6H3-3, 5- (CF3) 2) is similarly disrupted by the addition of NHC. (BDI) Ga (X) Zn (X) L2 complexes also react as a ‘masked’ source of I, as demonstrated by reactions with Et3NHCl and B (C6F5) 3, which yield the respective literature compounds (BDI) Ga (H) Cl and (BDI) Ga·B (C6F5) 3.