Mechanism of photoisomerization of 1-naphthyl-2-phenylethylenes in organic glasses
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Updated: Jul 10, 2026

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
Lan-Ying Yang1, Robert S H Liu
1Department of Chemistry, University of Hawaii, Honolulu, HI, USA.
Abstract:
Photoisomerization reactions of cis isomers of 1-beta-naphthyl-2-phenylethylene, an o-methylated homolog and 1-alpha-naphthyl-2-phenylethylene in organic glasses at liquid nitrogen temperature were studied. Reactions were followed by changes in UV-absorption spectra of the irradiated samples. Formation of an unstable trans-photoproduct was detected only with the o-methylated homolog. The results are consistent with high regioselective Hula-twist photoisomerization at the benzylic sites of the three compounds examined. Calculated data on relative energies of the conformers of both the cis and the trans isomers are in agreement with the suspected conformational population of the starting materials and the photoproducts.
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