Radiochemical study of the gas phase reaction of nucleogenic diethylsilylium ions with methanol and butanol

The gas phase ion–molecule reactions between alcohols (methanol and n-butanol) and nucleogenic diethylsilylium ions generated by the β-decay of the tritiated diethylsilane were studied by the radiochromatographic method. Among the labelled neutral products of the silylation of alcohols diethylsilylalkoxysilanes exhibit the major yield. Diethyl-butoxysilane contains not only n-butyl groups as in the substrate (21%), but also small amounts of s-butyl (5%) and t-butyl (7%) groups. In other alkoxysilanes the diethylsilyl group of the nascent nucleogenic cation is rearranged and isomerized. Products with the similar distribution of the silylium group isomers were observed earlier in the reaction of benzene, however the yield of the products with rearranged silylium groups was substantially greater for benzene. This difference in the yield of the products with rearranged silylium groups between benzene and alcohols is rationalized taking into account the more acidic character of the proton in the adduct oxonium ions.