Solvent-Dependent Oxidative Addition and Reductive Elimination of H 2 Across a Gallium-Zinc Bond.

H 2 adds reversibly across the metal-metal bond of [(BDI)Ga(H)-Zn(tmeda)(thf)][BAr 4 F ] (BDI=[HC{C(CH 3 )N(2,6-iPr 2 -C 6 H 3 )} 2 ] - , TMEDA=N,N,N',N'-tetramethylethylenediamine, BAr 4 F- =[B(C 6 H 3 -3,5-(CF 3 ) 2 ) 4 ] - ). Due to the stabilising effect of solvent coordination, hydrogenation products [(BDI)GaH 2 ] and [(tmeda)ZnH(thf)][BAr 4 F ] are favoured in THF solution, but THF-free mixtures of [(BDI)GaH 2 ] and [(tmeda)ZnH(OEt 2 )][BAr 4 F ] are predisposed towards entropically driven dehydrogenation to [(BDI)Ga(H)-Zn(tmeda)][BAr 4 F ] in fluorobenzene solution.