A cobalt molecular catalyst for hydrogen evolution reaction with remarkable activity in phosphate buffered water solution†

Abstract

Herein, we show that [Cp*Co(2-ampy)I]I (2-ampy = 2-aminomethyl-pyridine) is an extremely active catalyst for HER, exhibiting a TOF of 109 000 s⁻¹ in phosphate buffered water solution (pH 7). The key to this remarkable activity stems from the establishment of a network of weak interactions in the second coordination sphere. As a matter of fact, both experimental and theoretical studies strongly suggest that the –NH₂ functionality of the 2-ampy ligand acts as an anchoring and orienting group for H₂PO₄⁻ through the establishment of an intermolecular hydrogen bonding with it that, in turn, intermolecularly donates a proton to Co–H liberating H₂.