Characterization of Reactive Sites in Supported Catalysts by 51V/15N Rotational Echo Double Resonance NMR Spectroscopy: Formation of Phenylimido Groups at Surface-Bound Oxovanadi
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- 作者：Carole Brown ; Randall Achey ; Riqiang Fu ; Thomas Gedris ; and A. E. Stiegman
- 刊名：Journal of the American Chemical Society
- 出版年：2005
- 出版时间：August 24, 2005
- 年：2005
- 卷：127
- 期：33
- 页码：11590 - 11591
- 全文大小：42K
- 年卷期：v.127,no.33(August 24, 2005)
- ISSN：1520-5126
文摘
Silica-supported oxovanadium groups were reacted in a gas-solid reaction with aniline at 175 
C. The reaction was clean as monitored in situ by UV-vis spectroscopy and resulted in the elimination of water as the principal product of the reaction and the disappearance of the terminal V=O stretch in the Raman spectrum. 15N MAS solid-state NMR spectroscopy showed only a single nitrogen-containing species on the surface. Proton-dephased 15N NMR showed only weak attenuation of its intensity, indicating that there are no protons directly bonded to the nitrogen. The formation of a vanadium-imido covalent bond was characterized by 51V/15N rotational echo double resonance NMR spectroscopy where the quadrupolar 51V nucleus was monitored and the spin-1/2 15N nucleus was dephased.
C. The reaction was clean as monitored in situ by UV-vis spectroscopy and resulted in the elimination of water as the principal product of the reaction and the disappearance of the terminal V=O stretch in the Raman spectrum. 15N MAS solid-state NMR spectroscopy showed only a single nitrogen-containing species on the surface. Proton-dephased 15N NMR showed only weak attenuation of its intensity, indicating that there are no protons directly bonded to the nitrogen. The formation of a vanadium-imido covalent bond was characterized by 51V/15N rotational echo double resonance NMR spectroscopy where the quadrupolar 51V nucleus was monitored and the spin-1/2 15N nucleus was dephased.