• Journal of Photoscience
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• v.5 no.4
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• pp.143-148
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• 1998

Photoaddition reactions of ο-benzoquinones to some organic molecules were ivestigated to yield three types of photoadducts. Irradiation (350nm UV light) of a dichloromethane solution of tetrahal-1, 2- benzoquinones and 1, 4-diphenylbutadiene yielded 1, 3-dienes, which was found to be used to synthesize 1-phenylphenanthrenes. The 1, 3-dienes were also produced, when irradiated tetrahalo--1, 2-benzoquinones and 1,4-dipenylbut-1-en-3-yne in the similar conditions, which was applied to get 9-phenylphenanthrenes. An enolic compound come from the tautomerization of dibenzoylmethane was found to add to ο-benzoquinones to give, 1, 4-dioxenes and 1, 5-diketones as the major products. Although depenylbutadiyne did not add to ο-benzoquinones, diphenylacetylene added to ο-benzoquinones to give $\rho$-quinomethanes as well as two isomeric $\rho$-quinomethanes. One-way photoisomerism was observed for two isomeric $\rho$-quinomethanes.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.247-253
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• 2019

In this study, compounds with azo-mesogenic groups at 4-, 3,5-, or 3,4,5-positions of one phenyl ring were synthesized, and their liquid crystallinity and photochemistry were investigated. The compounds in the Azo1 and Azo2 series had linear and planar geometries, respectively, while those in the Azo3 series had relatively bulky structures. Compounds of BA-Azo2 and BA-Azo3 did not show any liquid crystallinity. Compounds of BE-Azo1 and BE-Azo2 exhibited a monotropic liquid crystallinity, while the other compounds showed an enantiotropic liquid crystallinity. The liquid crystalline behavior was imparted by the azo-mesogenic groups, and most of the liquid crystalline compounds formed a smectic phase. All the RM-AzoX compounds exhibited photoisomerism because of the presence of the azo groups in the molecule. The rate of photoisomerization followed the order of RM-Azo3 < RM-Azo1 < RM-Azo2 and was considered to depend on the steric hindrance around the azobenzene groups in the molecule. These results suggest that the liquid crystallinity and photochemical property of the compounds are affected by the position or the number of azo-mesogenic groups phenyl ring of the molecule.