Near thermal, selective liberation of hydrogen from formic acid catalysed by copper hydride ate complexes

Abstract

A near thermal two-step catalytic cycle for the selective release of hydrogen from formic acid by mononuclear cuprate anions was revealed using multistage mass spectrometry experiments, deuterium labelling and DFT calculations. In gas-phase ion-molecule reactions, mononuclear copper hydride anions [(L)Cu(H)]− (where L = H−, O2CH−, BH4− and CN−) were found to react with formic acid (HCO2H) to yield [(L)Cu(O2CH)]− and H2. The copper formate anions [(L)Cu(O2CH)]− can decarboxylate via collision-induced dissociation (CID) to reform the copper hydride [(L)Cu(H)]−, thereby closing the two-step catalytic cycle. Analogous labelling experiments with d1-formic acid (DCO2H) reveal that the decarboxylat..