Mechanisms for CO Production from CO2 Using Reduced Rhenium Tricarbonyl Catalysts
Mechanisms for CO Production from CO2 Using Reduced Rhenium Tricarbonyl Catalysts
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DOI：
10.1021/ja2105834
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发表时间：
2012-03-21
影响因子：
15
通讯作者：
Muckerman, James T.
中科院分区：
文献类型：
--
作者：
Agarwal, Jay;Fujita, Etsuko;Muckerman, James T.
二氧化碳的化学转化已经被许多实验小组研究过。特别是基于三羰基的分子催化剂的使用由于其吸收光、储存氧化还原当量和将CO2转化为更高能量产物的能力而引起了人们的兴趣。这些催化剂介导还原，特别是CO和HCOO-的机制知之甚少，旨在阐明反应途径的研究可能受到溶液中存在的大量物种的阻碍。本文用密度泛函理论研究了三羰基催化剂制备一氧化碳的反应机理。该研究来自Meyer小组的实验工作（J. Chem. Soc.，化学通信1985，1414-1416）和Fujita的小组（J. Am. 2003，125，11976-11987）在无水DMF中的溶液中。后者使用简化的反应混合物进行工作，该反应混合物去除了具有牺牲供体的光诱导还原步骤，用于验证所提出的机制，该机制涉及形成二羧酸二聚体[Re（dmb）（CO）（3）]（2）（OCO），其中dmb = 4，4 '-二甲基-2，2'-联吡啶。CO2插入到该物种中，随后重排，提出产生CO和碳酸根桥联的[Re（dmb）（CO）（3）]（2）（OCO 2）。提出的反应路径的结构和能量，并与以前发表的实验观察。
The chemical conversion of CO2 has been studied by numerous experimental groups. Particularly the use of rhenium tricarbonyl-based molecular catalysts has attracted interest owing to their ability to absorb light, store redox equivalents, and convert CO2 into higher-energy products. The mechanism by which these catalysts mediate reduction, particularly to CO and HCOO-, is poorly understood, and studies aimed at elucidating the reaction pathway have likely been hindered by the large number of species present in solution. Herein the mechanism for carbon monoxide production using rhenium tricarbonyl catalysts has been investigated using density functional theory. The investigation presented proceeds from the experimental work of Meyer's group (J. Chem. Soc., Chem. Commun. 1985, 1414-1416) in DMSO and Fujita's group (J. Am. Chem. Soc. 2003, 125, 11976-11987) in dry DMF. The latter work with a simplified reaction mixture, one that removes the photo-induced reduction step with a sacrificial donor, is used for validation of the proposed mechanism, which involves formation of a rhenium carboxylate dimer, [Re(dmb)(CO)(3)](2)(OCO), where dmb = 4,4'-dimethyl-2,2'-bipyridine. CO2 insertion into this species, and subsequent rearrangement, is proposed to yield CO and the carbonate-bridged [Re(dmb)(CO)(3)](2)(OCO2). Structures and energies for the proposed reaction path are presented and compared to previously published experimental observations.