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811.
Gerald Steiner Olesya Savchuk Hella Mller Dirk Ferse Hans‐Jürgen Adler Reiner Salzer 《Macromolecular Symposia》2001,164(1):159-166
Self assembly monolayers of octadecyltrichlorosilane Cl3‐Si‐(CH2)17‐CH3 and 17‐cyanopentadecyltrichlorosilane Cl3‐Si‐(CH2)17‐CN on silicon wafers have been prepared by adsorption from solution. The molecular orientation within the monolayers was investigated by using Polarisation Modulation FTIR spectroscopy. Quantitative analysis reveals that both types of silanes – monofunctionalised and bifunctionalised – form highly ordered monolayers. A high degree of ordering as well as a small tilt angel of the molecular backbones with respect to the surface normal are indicated by the strength of the Si‐O‐Si stretching modes and the weakness of the CH2 stretching modes. The decomposition of the terminal nitrile group of the substituted silane into a carboxyl group could be identified. The decomposition is caused by a high local HCl concentration, which develops upon binding of 17‐cyanopentadecyltrichlorosilane to the OH groups of the silicon surface. 相似文献
812.
Jakob Lebon Alexandros Mortis Dr. Cäcilia Maichle-Mössmer Dr. Manfred Manßen Dr. Peter Sirsch Prof. Dr. Reiner Anwander 《Angewandte Chemie (International ed. in English)》2023,62(6):e202214599
Commercially available stock solutions of organolithium reagents are well-implemented tools in organic and organometallic chemistry. However, such solutions are inherently contaminated with lithium halide salts, which can complicate certain synthesis protocols and purification processes. Here, we report the isolation of chloride-free methyllithium employing K[N(SiMe3)2] as a halide-trapping reagent. The influence of distinct LiCl contaminations on the 7Li-NMR chemical shift is examined and their quantification demonstrated. The structural parameters of new chloride-free monomeric methyllithium complex [(Me3TACN)LiCH3], ligated by an azacrown ether, are assessed by comparison with a halide-contaminated variant and monomeric lithium chloride [(Me3TACN)LiCl], further emphasizing the effect of halide impurities. 相似文献
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Near-infrared (NIR) reflection spectroscopy was used to determine the conversion in acrylate coatings after UV photopolymerization in order to test it as a method for process control in UV curing. A probe head was developed which is adapted to the specific requirements of UV curing and which is linked to a photodiode array spectrometer by an optical fiber. Reflection spectra from thin acrylate layers which were taken in intervals down to the millisecond range have shown an excellent signal-to noise ratio. Quantitative conversion data show good correlation with results from independent reference methods (FTIR, HPLC). Following thesebasic investigations, it was demonstrated that NIR reflection spectroscopy can be used for on-line monitoring of the acrylate conversion in thin coatings. Some examples of such investigations in pilot scale are presented. 相似文献