Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown
Published: March 5, 2025
Four mononuclear copper(II) complexes, [(DPA-OH)Cu(CH3OH)(ClO4)](ClO4) (1), [(DPA-OMe)Cu(CH3OH)(ClO4)](ClO4) (2), [(6-Amide-DPA-OMe)Cu](ClO4)2 (3) and [(6-Amide2-DPA-OMe)Cu](ClO4)2 (4), of flexidentate ligands bearing hemilabile (hydroxy)methoxyethyl and/or amide group on DPA (di(2-picolyl)amine) backbone were isolated to explore their potency in catalyzing chemical electrochemical oxygen reduction reaction (ORR). The role a arm, as well functionality the ligand affecting rate-determining step (RDS) overall catalytic cycle has been explored compared with that analogous [(tmpa)Cu](ClO4)2 (tmpa = tris(2-pyridylmethyl)amine) [(PV-tmpa)Cu](ClO4)2 (PV-tmpa bis(pyrid-2-ylmethyl){[6-(pivalamido)pyrid-2-yl]methyl}-amine) complexes. arm these complexes results an third-order rate, kcat values ranging from 103 104 M-2s-1 during dioxygen catalysis. All except complex 4 selectively reduce via 4e-/4H+ pathway water (H2O) using decamethylferrocene (Fc*) sacrificial reductant acidic acetone at 298 K. In contrast, altering conditions ambiance phosphate buffer displays reverse order ORR activity while maintaining same product selectivity observed catalysis acetone.
Language: Английский