The initial steps of the thermal decomposition of silanes in the gas phase were examined by DFT-B3LYP calculations, with particular attention being paid to the way in which the reactivity pattern changes with the degree of branching of the silane. Besides the established pathways1,2-hydrogen shift, H2 elimination, and homolytic dissociation1,3-hydrogen shift was also explored as an initial reaction step which leads to disilene structures. Subsequent silylene insertion and initial steps of radical chain reactions were also studied. To estimate the energetic changes with temperature, various reaction free energies and the corresponding activation free energies up to 650?degrees C were calculated. Accordingly, the leading reaction channel at room temperature is 1,2-hydrogen shift with subsequent silylene insertion; for higher degrees of branching, competing pathways (homolytic dissociation, 1,3-hydrogen shift, and radical polymerization) gain in relative importance. At high temperatures, the rate-determining step changes to homolytic dissociation, and thereby the apparent rates of decomposition become dependent on the degree of branching.     «

The initial steps of the thermal decomposition of silanes in the gas phase were examined by DFT-B3LYP calculations, with particular attention being paid to the way in which the reactivity pattern changes with the degree of branching of the silane. Besides the established pathways1,2-hydrogen shift, H2 elimination, and homolytic dissociation1,3-hydrogen shift was also explored as an initial reaction step which leads to disilene structures. Subsequent silylene insertion and initial steps of radica...     »

ISI Document Delivery No.: 971RQ Times Cited: 0 Cited Reference Count: 84 Eger, Wilhelm A. Genest, Alexander Roesch, Notker Wacker Chemie AG; Fonds der Chemischen Industrie We thank Drs. J. Stohrer, A. Bockholt, and D. Troegel (Wacker Chemie AG) as well as Dr. L. V. Moskaleva (Universitat Bremen) for valuable discussions. This work was supported by Wacker Chemie AG and Fonds der Chemischen Industrie. We gratefully acknowledge a generous allotment of computing resources at Leibniz Rechenzentrum Munchen. 0 Wiley-v c h verlag gmbh Weinheim     «

ISI Document Delivery No.: 971RQ Times Cited: 0 Cited Reference Count: 84 Eger, Wilhelm A. Genest, Alexander Roesch, Notker Wacker Chemie AG; Fonds der Chemischen Industrie We thank Drs. J. Stohrer, A. Bockholt, and D. Troegel (Wacker Chemie AG) as well as Dr. L. V. Moskaleva (Universitat Bremen) for valuable discussions. This work was supported by Wacker Chemie AG and Fonds der Chemischen Industrie. We gratefully acknowledge a generous allotment of computing resources at Leibniz Rechenzentrum...     »