Substitution- and Temperature-Effects on Hemithioindigo Photoisomerization – The Relevance of Energy Barriers

Abstract

The kinetics of the Z/E-photoisomerization of Hemithioindigo-compounds (HTI) with variations of substitution and temperature are investigated using transient absorption spectroscopy in the visible spectral range. The existence of potential energy barriers in the excited state is demonstrated. These barriers mainly determine the photoisomerization time.Effective tuning of the barriers can be achieved by adequate chemical substitution.