NHC-Induced Dismutation of Gallium–Zinc Bonds

The insertion of gallium(I) reagent [(BDI)GaI] (I, BDI = HC{C(CH3)Ndipp}2; 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].