Cobalt(II) tris(2-pyridylmethyl)amine complexes [Co(TPA)X]+ bearing coordinating anion (X = Cl−, Br−, I− and NCS−): synthesis and application for carbon dioxide reduction. (29th March 2017)

• Record Type: Journal Article
• Authors: Chan, Sharon Lai-Fung; Lam, Tsz Lung; Yang, Chen; Lai, Jing; Cao, Bei; Zhou, Zhongyuan; Zhu, Qihao
• Is Part Of: Polyhedron. Volume 125(2017)
• Page Start: 156
• Page End: 163
• Publication Date: 2017-03-29
• Subjects: Carbon dioxide reduction -- Cobalt tripodal ligands -- Anion effect -- Visible-light driven -- Density functional theory (DFT) calculation; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2016.09.049
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: Four cobalt(II) complexes supported by tetradentate tripodal ligand tris-(2-pyridylmethyl)amine (TPA) and ancillary coordinated anion (X), [Co(TPA)X] + (X = Cl −, Br −, I − and NCS − ) have been prepared. Among them, [Co(TPA)Br] + showed the best CO2 reduction performance with TON(CO) > 1400 over 65 h. Abstract: Four cobalt(II) complexes supported by the tripodal ligand tris(2-pyridylmethyl)amine (TPA) and ancillary coordinated anion (X), [Co(TPA)X] + (X = Cl −, Br −, I − and NCS − ) (1 –4 ), have been prepared. Magnetic susceptibility measurement and electronic spectroscopy indicate that they are five-coordinated high spin cobalt(II) complexes. The structures of2 –4 have been determined by X-ray crystallography. Reduction of CO2 to CO has been observed upon irradiation of complexes1 –4 in the presence of fac -Ir(ppy)3 (ppy = C-deprotonated 2-phenylpyridine anion) and under CO2 atmosphere using blue LEDs. All of these Co complexes were found to be efficient and stable CO2 reduction catalyst with TON(CO) > 1000 and CO selectivity > 90% under 65 h of irradiation. Among them, [Co(TPA)Br] + showed the best performance in CO2 reduction with TON(CO) > 1400 after 65 h. The coordinated anion X played an important role in the photo-catalysis. Density functional theory (DFT) calculation has also been performed to examine the mechanism and role of coordinated anion X in visible-light induced CO2 reduction.