Mechanistic studies of CO_2 reduction to methanol mediated by an N-heterocyclic germylene hydride

摘要

The labile germylene hydride L~(Cy)GeH is capable of activating CO_2 affording the corresponding formate L~(Cy)GeOCH(vO) (2) (L~(Cy) = cyclo-C_6H_8-1-NAr-2-C(Ph)NAr, Ar = 2,6-iPr_2C_6H_3). Compound 2 and the previously reported LGeOCH(vO) (L = CH(MeCvNAr)2, Ar = 2,6-iPr2C6H3) (2') could be further converted to methanol with the AlH3·NMe3 alane-amine adduct as a hydrogen source upon workup with water. A plausible mechanism for the conversion of the formate complexes to methanol is proposed based on additional results from the conversion of 2' with the milder hydride delivery agent LAlH_2.