Photocyclization of trans-1-(1-naphthyl)-2-(3-hydroxyphenyl)ethene: evidence for adiabatic 1trans*->1cis* photoisomerization

The photochemistry of trans- and cis-1-(1'-naphthyl)-2-(3-hydroxyphenyl) ethene in cyclohexane and acetonitrile was examined. In cyclohexane fluorescence is the main deactivation channel for the (1)trans* isomer while photocyclization is the main reaction of the (1)cis* isomer. The weighty formation of hydroxychrysene following one photon absorption by the trans isomer furnished evidence of an adiabatic (1)trans*-->(1)cis* isomerization. The photoreactivity data in acetonitrile indicated the influence of solvent polarity on the shape of the excited state surface.