Pincer chromium(ii)-catalyzed hydrogenation of CO2 and bicarbonate to formate

Abstract

We report here the catalytic hydrogenation of carbon dioxide to formate using a Cr(II) pincer complex. The complex CrCl₂(PNP) C-1 {PNP = N,N-bis(diphenylphosphinoethyl)amine} in combination with NaHBEt₃ in the presence of NaOH in a THF : H₂O mixture yielded formate after 48 h with a TON of up to 8700. The complex C-1 was also found to be an active catalyst for the hydrogenation of sodium bicarbonate, furnishing formate with up to 62% yield. Stoichiometric experiments were carried out based on which a probable mechanism involving metal–ligand cooperation is proposed.