X-ray induced degradation of surface bound azido groups during XPS analysis

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.

Electroactive Metal Complexes Covalently Attached to Conductive PEDOT Films: A Spectroelectrochemical Study

“… , The N 1s peaks of N 3 -PEDOT have two main components at binding energies of 404.6 and 400.8 eV, which is typical of N 3 groups on polymer surfaces and can be assigned to the relatively electron deficient central nitrogen (N N N) and the two partially negatively charged nitrogen atoms ( N N N ) of the N 3 group, respectively . The ratio of the area of the two peaks is approximately 1:3 instead of the expected 1:2, which is likely due to the photodegradation of the azide groups to N 2 and nitrene intermediates caused by the X-ray irradiation. ,− Furthermore, the relative N/S elemental ratio for the N 3 -PEDOT film (3.1) is close to the expected theoretical value of 3.0 (one N 3 per thiophene moiety). The N/S ratio for the 1:2N 3 -PEDOT:PEDOT copolymer (1.1) film is consistent with the value of 1 expected for the stated copolymer composition of 1:2 N 3 -EDOT:EDOT (one N 3 per three thiophene moieties), despite the 1:4 ratio of the N 3 -EDOT:EDOT monomers employed (Figure A, see previous section).…”

Cross-linked polymer microparticles with tunable surface properties by the combination of suspension free radical copolymerization and Click chemistry

“…S4). A more likely explanation is the de-N-alkylation reaction of the 1,2,3-triazolium groups and the reactivity of iodide groups during XPS analysis which has been previously reported [64]. Finally, anion exchange reaction between the surface 1,2,3-triazolium iodide groups of µPs MP5 and cresol red sodium salt fluorescent dye afforded fluorescently labeled µPs MP6.…”

Reversibly Cross-Linking Polymer Brushes Using Interchain Disulfide Bonds

“…Because of the partial decomposition of the azide groups during the XPS analysis, however, this percentage is an underestimation of the actual AzHPMA content of the copolymer brush. 34,35 It is also important to note that XPS only probes the top-10 nm of the brush and does not sample the entire polymer brush film.…”

“…The area ratio b / c is 2.5:1, which is higher than the theoretical peak area ratio of 2:1. This discrepancy is attributed to partial degradation of the azide groups during the XPS analysis, , which results in the formation of amine species “blue ■” that appears at 399.2 eV in the N 1s high-resolution scan. The N 1s high-resolution scan of the copolymer brush shows the azide components “ b ” (400.8 eV) and “ c ” 404.6 eV.…”