Surprising Coordination Chemistry of Cu+ Cations in Zeolites: FTIR Study of Adsorption and Coadsorption of CO, NO, N2, and H2O on Cu鈥揨SM-5
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- 作者：Videlina Zdravkova ; Nikola Drenchev ; Elena Ivanova ; Mihail Mihaylov ; Konstantin Hadjiivanov
- 刊名：Journal of Physical Chemistry C
- 出版年：2015
- 出版时间：July 9, 2015
- 年：2015
- 卷：119
- 期：27
- 页码：15292-15302
- 全文大小：453K
- ISSN：1932-7455
文摘
Cations exchanged in zeolites are generally characterized by a low coordination number and can thus attach simultaneously more than one small guest molecule. For instance, Cu+ ions in ZSM-5 can accept, at low temperature, up to three CO and up to two NO molecules. However, only one N2 molecule can be coordinated to such sites. Although mixed aqua-carbonyl and aqua-dinitrogen complexes are formed, no mixed carbonyl-nitrosyl, carbonyl-dinitrogen, or nitrosyl-dinitrogen species can be produced. Thus, adsorption of NO on CO precovered sample results in segregation of the CO adsorption layer according to the reaction: 2Cu+鈥揅O + 2NO 鈫?Cu+(CO)2 + Cu+(NO)2. Adsorption of N2 on NO precovered sample leads to a similar process: 2Cu+鈥揘O + N2 鈫?Cu+(NO)2 + Cu+鈥揘2. No carbonyl-dinitrogen complexes are produced during CO鈥揘2 coadsorption. The role of the ligand and the nature of the bond in the formation of geminal and mixed-ligand complexes are discussed.