Amidines as Effective Ancillary Ligands in Copper-catalyzed Hydrogenation of Carbon Dioxide

Mononuclear Cu(II) complexes bearing a bidentate bisamidine ligand were newly synthesized and characterized. The catalytic activity was evaluated in the hydrogenation of carbon dioxide to formate salts. A substantial enhancement of the catalyst turnover number was achieved by the imidazoline-based complex, indicating that amidines serve as effective ancillary ligands for homogeneous copper catalysis. Mononuclear Cu(II) complexes bearing a bidentate bisamidine ligand were newly synthesized and characterized. The catalytic activity was evaluated in the hydrogenation of carbon dioxide to formate salts. A substantial enhancement of the catalyst turnover number was achieved by the imidazoline-based complex, indicating that amidines serve as effective ancillary ligands for homogeneous copper catalysis.