Abstract
Dynamic solvent effect on the isomerization of two 2-alkenylanthracene derivatives in the lowest excited singlet (S1) state was investigated. The isomerization rates were determined in supercritical fluids (SCF) and in a series of compressed liquid n-alkane solvents. Kramer's turnover behavior was observed. The maximum rate is substantially smaller than expected from transition state theory. Torsional potentials between anthracene ring and alkene plane for the isomerization reaction coordinate of 2-alkenylanthracene were calculated by ab initio method as a function of dihedral angle. It was confirmed by the calculation that the isomerization followed by experiment is from s-trans to s-cis conformers.