Control of the photoisomerization mode of carbon-carbon double bond by intramolecular hydrogen bond;: One-way photoisomerization of 2′-hydroxychalcone induced by adiabatic intramolecular hydrogen atom transfer

To investigate the effect of intramolecular hydrogen bonding on the photoisomerization of carbon-carbon double bond, photoisomerization of 2'-hydroxychalcone has been studied. Based: on the quantum yield measurements and laser flash photolysis studies, it was found that 2'-hydroxychalcone isomerized only from cis- to trans-isomer. The one-way cia-trans isomerization is induced by the adiabatic hydrogen atom transfer in the triplet state.