Simultaneous Two-Hydrogen Transfer as a Mechanism for Efficient CO2 Reduction
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- 作者：Paul M. Zimmerman ; Zhiyong Zhang ; Charles B. Musgrave
- 刊名：Inorganic Chemistry
- 出版年：2010
- 出版时间：October 4, 2010
- 年：2010
- 卷：49
- 期：19
- 页码：8724-8728
- 全文大小：752K
- 年卷期：v.49,no.19(October 4, 2010)
- ISSN：1520-510X
文摘
Two-hydrogen transfer (simultaneous protic and hydridic hydrogen transfer) is examined as a potentially efficient mechanism for the selective reduction of CO2 to methanol. High-level ab initio CCSD(T) coupled-cluster theory simulations of ammonia−borane (AB), which contains both protic and hydridic hydrogen, show the effectiveness of this mechanism. AB demonstrates how simultaneous two-hydrogen transfer is kinetically efficient because (1) two-hydrogen transfer avoids high-energy single-electron-reduced intermediates, (2) the CO2’s HOMO is protonated while the LUMO is concurrently reduced by a hydride, and (3) complementary charge polarities around the six-membered-ring transition-state structures stabilize the transition states. This study suggests that an effective mechanism for the reduction of CO2 to methanol proceeds through three two-hydrogen-transfer steps and that suitable catalysts should be developed that exploit two-hydrogen transfer without the use of AB.