Photochemistry of ethyltrimethylstannane and n-propyltrimethylstannane at 185 nm

Ethyltrimethylstannane vapour (ets) yields several gaseous hydrocarbons on photolysis together with a yellow polymer which deposits on the cell window. Addition of nitrogen or argon (130 mbar) reduces the yields by 90 % but there is a residual reaction which is unaffected by pressure of inert gas. Addition of oxygen reduces some yields to zero. The major primary reactions are C2H5Sn(CH3)3+hν(λ= 185 nm)→C2H4+(CH3)3SnH, ϕ∼0.40; →C2H5+CH3+Sn(CH3)2, ϕ∼0.55. The quantum yields of formation of the radical products are increased by radical abstraction from the stannane. Similar results were found for propyltrimethylstannane (pts) but the principal free radical reaction is C3H7Sn(CH3)3+hν(λ= 185 nm)→ C3H7+ 2CH3+ Sn(CH3). The quenching effect is attributed to the deactivation of one of the two excited state precursors of the reaction.