Mechanistic studies of CO2 reduction to methanol mediated by an N-heterocyclic germylene hydride.

The labile germylene hydride L(Cy)GeH is capable of activating CO2 affording the corresponding formate L(Cy)GeOCH([double bond, length as m-dash]O) (2) (L(Cy) = cyclo-C6H8-1-NAr-2-C(Ph)NAr, Ar = 2,6-iPr2C6H3). Compound and the previously reported LGeOCH([double bond, length as m-dash]O) (L = CH(MeC[double bond, length as m-dash]NAr)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 with the milder hydride delivery agent LAlH2.