Action of Electron-Accepting Quenchers in Photoisomerization of Naphthylethylenes in Polar and Nonpolar Solvents

The quantum yield of trans-cis isomerization of 3,3-dimethyl-1-(2-naphthyl)-1-butene was measured in the presence of various electron-accepting quenchers in benzene or in acetonitrile. In benzene the quantum yield was increased by addition of some of the quenchers; however, in acetonitrile it was decreased under similar conditions. This was attributed to more efficient formation of olefin triplets through an exciplex in benzene than through radical ion pairs in acetonitrile.