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

H-2 adds reversibly across the metal-metal bond of [(BDI)Ga(H)-Zn(tmeda)(thf)][BAr4F] (BDI=[HC{C(CH3)N(2,6-iPr(2)-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.

Automated summary

H-2 adds reversibly across the metal-metal bond of [(BDI)Ga(H)-Zn(tmeda)(thf)][BAr4F]. The stabilization effect of solvent coordination favors the formation of [(BDI)GaH2] and [(tmeda)ZnH(thf)][BAr4F] in THF solution, while 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.