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Updated: Jun 4, 2026

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Oxyallyl exposed: an open-shell singlet with picosecond lifetimes in solution but persistent in crystals of a
Gregory Kuzmanich1, Fabian Spänig, Chao-Kuan Tsai
1Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1559, USA.
Abstract:
Photoinduced decarbonylation of 2,4-bis(spirocyclohexyl)-1,3-cyclobutanedione 1 in the crystalline solid state resulted in formation of a deep blue transient with λ(max) = 550 nm and a half-life of 42 min at 298 K, identified as kinetically stabilized oxyallyl. Support for an open-shell singlet species was obtained by spectroscopic analysis and (4/4) CASSCF calculations with the 6-31+G(d) basis set and multireference MP2 corrections. The electronic spectrum of the singlet biradical, confirmed by femtosecond pump-probe studies in solution, was matched by coupled cluster calculations with single and double corrections.
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