A Dinuclear Cobalt Cryptate as a Homogeneous Photocatalyst for Highly Selective and Efficient Visible‐Light Driven CO₂ Reduction to CO in CH₃CN/H₂O Solution

Abstract

A dinuclear cobalt complex [Co₂ (OH)L¹ ](ClO₄ )₃ (1, L¹ =N[(CH₂ )₂ NHCH₂ (m-C₆ H₄ )CH₂ NH(CH₂ )₂ ]₃ N) displays high selectivity and efficiency for the photocatalytic reduction of CO₂ to CO in CH₃ CN/H₂ O (v/v=4:1) under a 450 nm LED light irradiation, with a light intensity of 100 mW cm^-2 . The selectivity reaches as high as 98 %, and the turnover numbers (TON) and turnover frequencies (TOF) reach as high as 16896 and 0.47 s^-1 , respectively, with the calculated quantum yield of 0.04 %. Such high activity can be attributed to the synergistic catalysis effect between two Co^II ions within 1, which is strongly supported by the results of control experiments and DFT calculations.