X‐ray induced degradation of surface bound azido groups during XPS analysis |
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| Authors: | Ali Saad Manef Abderrabba Mohamed M Chehimi |
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| Affiliation: | 1. Laboratory of Materials, Molecules and Applications, IPEST, University of Carthage, La Marsa, Tunisia;2. Faculté des Sciences de Tunis, Université El Manar, Tunis, Tunisia;3. Université Paris Est, ICMPE (UMR 7182), CNRS, UPEC, Thiais, France |
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| Abstract: | Mesoporous silica SBA‐15 was synthesized and silanized with azidopropyl triethoxysilane in order to design a clickable material. Fourier transform infrared analysis permitted to prove the attachment of the azidopropylene groups to SBA‐15 resulting in the reactive and functional material N3‐SBA‐15. X‐ray photoelectron spectroscopy was used to determine the surface composition of SBA‐15. However, we unexpectedly found that the surface bound azido groups undergo X‐ray induced decomposition during the X‐ray photoelectron spectroscopy analysis resulting in the formation of nitrenes. These are very reactive groups able to intercalate C―C and C―H bonds of the propylene chains as judged from the N1s peak shape. Possible mechanisms of intercalation are suggested. C1s and N1s peaks were recorded at different exposure time. N/C, N+/N and N+/C undergo exponential decay. N+/N reaches the value of zero in less than 80 min of exposure to the X‐ray source. The N+/C decay plot was fitted with first‐order kinetics, and the decomposition kinetic constant (kdec) was found to equal to 516.4 s?1. This is a fast X‐ray induced degradation which must be considered with care when examining clickable materials with surface bound alkyl azido groups. Copyright © 2016 John Wiley & Sons, Ltd. |
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| Keywords: | XPS X‐ray induced degradation kinetics click chemistry propylazide group |
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