Ahmed Md Estak, Rana Atanu, Saha Rajat, Dey Subal, Dey Abhishek
School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, Kolkata 700032, India.
Department of Chemistry, Kazi Nazrul University, Kalla, Asansol, Paschim Bardhaman 713340, India.
Inorg Chem. 2020 Apr 20;59(8):5292-5302. doi: 10.1021/acs.inorgchem.9b03056. Epub 2020 Apr 8.
The chemical and electrochemical reduction of CO to value added chemicals entails the development of efficient and selective catalysts. Synthesis, characterization and electrochemical CO reduction activity of a air-stable cobalt(III) diphenylphosphenethano-bis(2-pyridinethiolate)chloride [{Co(dppe)(2-PyS)}Cl, ] complex is divulged. The complex reduces CO under homogeneous electrocatalytic conditions to produce CO with high Faradaic efficiency (FE > 92%) and selectivity in the presence of water. Through detailed electrochemical investigations, product analysis, and mechanistic investigations supported by theoretical calculations, it is established that complex reduces CO in its Co(I) state. A reductive cleavage leads to a dangling protonated pyridine arm which enables facile CO binding through a H-bond donation and facilitates the C-O bond cleavage via a directed protonation. A systematic benchmarking of this catalyst indicates that it has a modest overpotential (∼180 mV) and a TOF of ∼20 s for selective reduction of CO to CO with HO as a proton source.
将CO化学还原和电化学还原为高附加值化学品需要开发高效且具有选择性的催化剂。本文报道了一种空气稳定的二苯基膦基乙醇双（2-吡啶硫醇）氯化钴（III）[{Co(dppe)(2-PyS)}Cl]配合物的合成、表征及电化学CO还原活性。该配合物在均相电催化条件下能将CO还原，在有水存在的情况下，产生CO的法拉第效率高（FE>92%）且具有选择性。通过详细的电化学研究、产物分析以及理论计算支持的机理研究，确定该配合物以Co（I）状态还原CO。还原裂解会产生一个悬挂的质子化吡啶臂，它通过氢键供体实现CO的轻松结合，并通过定向质子化促进C-O键的裂解。对该催化剂的系统基准测试表明，以H₂O作为质子源，将CO选择性还原为CO时，其过电位适中（约180 mV），TOF约为20 s⁻¹。
