Photocatalytic Reduction of CO 2 to CO Using Manganese Complexes with Bipyridine Modified Electron-Donating Groups

The present work deals with the Mn-based complex formed after substitution with groups (–NH 2 and –Br) on 2, 2′-bipyridine ligand and their photocatalytic activity for CO 2 reduction. The photocatalytic system involves [Ru(bpy) 3 ] 2+ [Ru] as a photosensitizer (PS) in a mixture of N, N-dimethylformamide (DMF) and triethanolamine (TEOA) and the 1-benzyl-1,4-dihydronicotinamide (BIH), BIH and TEOA as the sacrificial agent and the auxiliary sacrificial agent in photocatalytic system, respectively. The results revealed that electron-donating groups of the complexes play an essential role in the photocatalytic reaction. Both density functional and high-resolution mass spectrometry supported the process of photocatalytic reduction of CO 2 to CO in the presence of manganese complexes. Graphical Abstract Mn-based complex with 4,4′-diamine—2,2′-bipyridine as a ligand was synthesized. The photocatalytic CO 2 reduction behaviours of the catalysts were investigated. The plausible mechanisms were proposed based on the main intermediates detected by HRMS and DFT.