Reactions of methylsilane at the surfaces of nickel, rhodium and tungsten

Abstract

The chemisorption and reactions of methylsilane at the surfaces of films of nickel, rhodium and tungsten at 195 K and above have been investigated to determine how the metal-catalysed reactions of silanes differ from those of alkanes. Methylsilane chemisorption is accompanied by the formation of gas-phase hydrogen and methane and isotopic studies have shown that adsorption occurs through the silicon atom. Mutual exchange between CH₃SiH₃ and CH₃SiD₃ is catalysed by all three metals at 195 K. Exchange is confined to the silyl group and some poisoning occurs. Exchange between CH₃SiH₃ and D₂ is catalysed by the metals investigated but substantial poisoning of the reaction is observed. Surfaces poisoned by this reaction retain activity for mutual exchange. Mechanisms of exchange are proposed.