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Updated: Nov 3, 2025

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Helical electronic transitions of spiroconjugated molecules
Marc H Garner1, Clemence Corminboeuf1
1Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne 1015, Switzerland. clemence.corminboeuf@epfl.ch.
Abstract:
The two π-systems of allene can combine into helical molecular orbitals (MOs), yet the helicity is lost in the π-π* transitions due to excited state mixing. In spiroconjugated molecules the relative orientation of the two π-systems is different and consequently only half the π-MOs become helical. We show that the helicity of the electronic transitions of methyl-substituted spiropentadiene is symmetry protected. As a result, helical π-conjugation can manifest in observable electronic and chiroptical properties.
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