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

Abstract

The labile germylene hydride L^CyGeH is capable of activating CO₂ affording the corresponding formate L^CyGeOCH(O) (2) (L^Cy = cyclo-C₆H₈-1-NAr-2-C(Ph)NAr, Ar = 2,6-iPr₂C₆H₃). Compound 2 and the previously reported LGeOCH(O) (L = CH(MeCNAr)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 LAlH₂.