Patra Suman, Dinda Souvik, Ghosh Soumili, Roy Triparna, Dey Abhishek
School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata, WB 700032, India.
Proc Natl Acad Sci U S A. 2025 Jan 14;122(2):e2417764122. doi: 10.1073/pnas.2417764122. Epub 2025 Jan 7.
Molecular catalysts with a single metal center are reported to reduce CO to a wide range of valuable single-carbon products like CO, HCOOH, CHOH, etc. However, these catalysts cannot reduce CO to two carbon products like ethane or ethylene and the ability to form C-C from CO remains mostly limited to heterogeneous material-based catalysts. We report a set of simple iron porphyrins with pendant thiol group can catalyze the reduction of CO to ethane (CH) with HO as the proton source with a Faradaic yield >40% the rest being CO. The mechanism involves a CO-derived methyl group transfer to the pendant thiol akin to the proposal forwarded for methyl transferases and a follow-up C-C bond formation of the thioether thus formed and a Fe(II)-CH species generated by the reduction of a second molecule of CO. The availability of a "parking space" in the molecular framework for the first reduced C product from CO reduction allows C-C bond formation resulting in a unique case where a component of natural gas can be generated from direct electrochemical reduction of CO.
据报道，具有单一金属中心的分子催化剂可将CO还原为多种有价值的单碳产物，如CO、HCOOH、CHOH等。然而，这些催化剂无法将CO还原为乙烷或乙烯等二碳产物，从CO形成C-C键的能力大多仍局限于基于多相材料的催化剂。我们报道了一组带有侧链硫醇基团的简单铁卟啉，以HO作为质子源，能催化CO还原为乙烷（CH），法拉第产率>40%，其余产物为CO。该机理涉及一个源自CO的甲基转移至侧链硫醇，这类似于针对甲基转移酶提出的设想，以及后续由此形成的硫醚与通过还原第二个CO分子生成的Fe(II)-CH物种之间形成C-C键。分子框架中存在一个“停车位”，用于容纳CO还原产生的首个还原态C产物，这使得C-C键得以形成，从而出现了一种独特的情况，即可以通过CO的直接电化学还原生成天然气的一种成分。
