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Published on: May 29, 2018
Mechanism of photochromic transformations and photodegradation of an asymmetrical 2,3-diarylcyclopentenone
Maria V Oplachko1, Artem B Smolentsev, Ilya M Magin
1Novosibirsk State University, 2 Pirogova Str., 630090, Novosibirsk, Russian Federation. glebov@kinetics.nsc.ru.
Abstract:
A mechanistic study of the photochromic properties and photodegradation processes of an asymmetrical diarylcyclopentenone bearing thiophene and benzothiophene units using stationary photolysis, nanosecond laser flash photolysis and time-resolved luminescence was performed. It was found that the light-induced reversible isomerization of (3-(2,5-dimethyltiophen-3-il)-2-(2-methyl-1-benzylthiophen-3-il)cyclopent-2-en-1-one, compound 1) from open to closed form is a common photochromic transformation inherent to diarylethenes, while the photodegradation process proceeds in two ways. The first is a formal 1,2-dyotropic rearrangement, proceeding without the participation of oxygen. The second is the oxygen-dependent mechanism involving the excitation of the open form 1A into the triplet state, quenching of the latter by dissolved oxygen, and oxidation of the initial compound by singlet oxygen.
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