Solvent-Dependent Oxidative Addition and Reductive Elimination of H2 Across a Gallium-Zinc Bond

Abstract

H2 adds reversibly across the metal-metal bond of [(BDI)Ga(H)−Zn(tmeda)(thf)][BAr4F] (BDI=[HC{C(CH3)N(2,6-iPr2-C6H3)}2]−, TMEDA=N,N,N′,N′-tetramethylethylenediamine, BAr4F−=[B(C6H3-3,5-(CF3)2)4]−). Due to the stabilising effect of solvent coordination, hydrogenation products [(BDI)GaH2] and [(tmeda)ZnH(thf)][BAr4F] are favoured in THF solution, but THF-free mixtures of [(BDI)GaH2] and [(tmeda)ZnH(OEt2)][BAr4F] are predisposed towards entropically driven dehydrogenation to [(BDI)Ga(H)−Zn(tmeda)][BAr4F] in fluorobenzene solution.