School of Molecular Sciences, Arizona State University , Tempe, Arizona 85281, United States.
Department of Chemistry, University of Washington , Seattle, Washington 98105, United States.
J Am Chem Soc. 2017 Jan 25;139(3):1033-1036. doi: 10.1021/jacs.6b10806. Epub 2017 Jan 11.
We describe a new electrochemical cycle that enables capture and release of carbon dioxide. The capture agent is benzylthiolate (RS), generated electrochemically by reduction of benzyldisulfide (RSSR). Reaction of RS with CO produces a terminal, sulfur-bound monothiocarbonate, RSCO, which acts as the CO carrier species, much the same as a carbamate serves as the CO carrier for amine-based capture strategies. Oxidation of the thiocarbonate releases CO and regenerates RSSR. The newly reported S-benzylthiocarbonate (IUPAC name benzylsulfanylformate) is characterized by H and C NMR, FTIR, and electrochemical analysis. The capture-release cycle is studied in the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMP TFSI) and dimethylformamide. Quantum chemical calculations give a binding energy of CO to benzyl thiolate of -66.3 kJ mol, consistent with the experimental observation of formation of a stable CO adduct. The data described here represent the first report of electrochemical behavior of a sulfur-bound terminal thiocarbonate.
我们描述了一种新的电化学循环，能够捕获和释放二氧化碳。捕获剂是苄硫醇盐（RS），通过二苄基二硫（RSSR）的还原电化学产生。RS 与 CO 反应生成末端的、硫键合的单硫代碳酸盐 RSCO，它作为 CO 载体物种，与氨基甲酸酯作为基于胺的捕获策略的 CO 载体非常相似。硫代碳酸盐的氧化释放 CO 并再生 RSSR。新报道的 S-苄基硫代碳酸盐（IUPAC 名称为苄基硫代甲酸酯）通过 H 和 C NMR、FTIR 和电化学分析进行了表征。在离子液体 1-丁基-1-甲基吡咯烷双（三氟甲基磺酰基）亚胺（BMP TFSI）和二甲基甲酰胺中研究了捕获-释放循环。量子化学计算给出了 CO 与苄硫醇盐的结合能为-66.3 kJ mol，与形成稳定 CO 加合物的实验观察一致。这里描述的数据代表了第一个关于硫键合末端硫代碳酸盐的电化学行为的报告。
