Abstract

A series of experiments were carried out to spectroscopically identify intermediates in the trans-to-cis isomerization of stilbenes. The molecule used in these investigations is a fused ring analog of stilbene (A), trans-1,1’-biindanyldene (B). The photophysical properties of this "stiff" stilbene [1-3] are very similar to those of stilbene with the differences accounted for by a smaller barrier (1.5 kcal/mol) to isomerization [1] than in t-stilbene. This low barrier results in an extremely fast (3 ps in hexane) isomerization [2], thus providing an ideal system for investigation of twisted intermediates since it would cause an increased population of short-lived intermediate states compared with molecules with slower isomerization rates.

© 1984 Optical Society of America