USING THEORETICAL DESCRIPTORS TO MODEL SOLVENT EFFECTS IN THE ISOMERIZATION OF CIS-STILBENE

Experimental observations of the photoinduced excited-state lifetime o f cis-stilbene have shown a distinct dependence on solvation processes . The rate of decay, dominated by a cis-trans isomerization, is more r apid in polar solvents than in nonpolar solvents. Linear solvation ene rgy relationship (LSER) techniques show that this can be explained in terms of polarity and polarizability parameters for the solvent. Theor etical linear solvation energy relationship (TLSER) analysis shows tha t this can be explained in terms of solvent polarizability and electro static basicity. New TLSER descriptors based on calculated solvent bon d diplole parameters are also successful in describing this solvent de pendence. Solvent-dependent dipole moments are calculated for an appro ximate stilbene transition-state geometry using the polarizable contin uum model (PCM), which suggests the usefulness of a more detailed stud y of this photoisomerization process using current solvation theory an d computational techniques. (C) 1996 John Wiley & Sons, Inc.