Reactions of C=C Terminated Self-Assembled Monolayers in Gas-Phase Ozone

An important role in atmospheric chemistry is that of the count offions of ozone with un gross(a) fundamental surfaces. Potential reactions sites for the atmospheric pollutant ozone are man-made materials that mark C=C functional groups. Previous research has approaching into courtn that carboxylic point-containing products were formed when unsaturated organic monolayers on silicon react with ozone; a band at 1860cm-1 shows the formation of a strained carbonyl species; oxidation of Au - S checks in saturated self-assembled monolayers of alkanethiols on Au. This article explores the reaction mechanisms of ozone with unsaturated organic surfaces by using C=C terminated alkanethiol SAMs (self-assembled monolayers). This taste uses reprehension - adsorption infrared spectroscopy (RAIRS). A Bruker IFS 66v/S mass spectrometer with a liquid N2 - cooled MCT detector was apply to record the RAIR spectra. all(prenominal) spectrum was collected by using p-polarized light with an clean of light speed scans. Background references were clean Au substrates with a resolution of 2cm-1. To asperse the effects of background water and early(a) contaminants, the experiment was conducted in a high vacuum, with a thrust of 5x10-7Torr. The compass points obtained show the front man of a proportionate and symmetric stretching modes of the methylene units within the hydrocarbon chains. later exposure of the C=C-T SAM to about 1000L of ozone, the beaks associated with the double bonds disappear. This indicates reactions at the terminal C=C bond. The change in peak position and imprint of the spectra is attributed to the monolayer disordering. This disordering could include the effects of the terminal C=C bond reactions as well as oxidation of the Au - S bond. Next, exposure time is increased. This spectra obtained here suggests that the C=C-T SAM reacts with ozone to ab initio form a carboxylic acid intermediate that converts to a carboxylic anhydride group wi th more exposure. The RAIR spectra show that! SAM... If you want to get a full essay, order it on our website: BestEssayCheap.com

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