An ab initio and DFT study of some homolytic substitution reactions of methoxycarbonyl radicals at silicon, germanium, and tin

Abstract

Homolytic substitution reactions of methoxycarbonyl radicals at the silicon, germanium, and tin atoms in various dialkylsilanes, dialkylgermanes and dialkylstannanes have been investigated using computational techniques. Ab initio and DFT calculations predict that attack of methoxycarbonyl radical at the silicon containing molecules can proceed via both backside and frontside attack mechanisms. At the (CCSD(T)/DZP//BHandHLYP/DZP) level of theory, energy barriers (ΔE‡) of 93.9 and 103.3 kJ mol-1 are calculated for the backside and frontside reactions, respectively. Similar results are obtained for reactions involving germanium and tin with calculated energy barriers (ΔE‡) of 89.2 and 99.2 kJ ..