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A novel chiral photoswitch composed of a binaphthyl unit and a hexafluorocyclopentene ring has been synthesized. This chiral photoswitch exhibited thermally reversible photochromism between the binaphthyl and helicenoid forms based on 6π-electrocyclization. The helicity of the binaphthyl moiety was reversed upon stereospecific photocyclization and reverted back during the thermal ring opening. [ABSTRACT FROM AUTHOR]

The enantioselective synthesis of a novel photochronic helicenoid diarylethene (R)-1-[1-(1-methoxymethomyethyl)-2-naphtho[2,1-b]thienyl]-2-(2,4,5-trimethyl-3-thienyl)hexafluorocyclopentene is reported. The product showed highly diastereoselective photocyclization (90% de) and a large change (950 degree) in the specific optical rotation value at 633 nm upon ultraviolet (UV) light irradiation in ethyl acetate.

The synthesis, photochromism, and optical properties of a chiral heliconoid diarylethene that shows a large change in specific optical rotation induced by photochromism is reported. The diarylethene possessing one [4]thiaheterohelicene and one benzothiophene with a chiral methoxymethoxyethyl group on its C-3 position was proved to work as a switch of specific optical rotation at a wavelength at which both colored and colorless forms have no absorption in solution.

This review traces the history and evolution of the photochromic compounds, the fulgides. The compounds exhibit photochromic properties from the aromatic ring on the exo-methylene carbon atom. Research efforts toward developing fulgides for their use in photon-controlled memory devices and switches are discussed.

The synthesis of the first thermally irreversible, diastereoselective photochromic system, (R)-binaphthol-condensed indolylfulgide, has been accomplished. Specifically, two indolylfulgides with a 1-(1,2-dimethyl-3-indolyl)-2-methylpropylidene group and a 1-(1,2-dimethyl-3-indolyl)butylidene group were prepared. According to observations, the latter possesses the best thermal stability and fatigue resistivity toward the iterative photochromic interconversion process among fulgide derivatives.

Photosublimation of the photoproduct of ethyl-4-formyl-1,3-dimethylpyrazole-5-carboxylate(EFDPC) is studied at room temperature and normal atmospheric pressure. It is observed that the unprecedented localized heating due to absorbed photon energy exceeds the activation energy for sublimation resulting in evaporation of the molecules from the substrate surface.

Fine‐tuning of the molecular structure of organic bistable compounds to improve their photochromic performance or to introduce additional functions remains an important issue in the development of photoresponsive materials. Diarylethenes bearing heterocyclic moieties belong to the most intensively studied class of organic photochromes due to their excellent photochemical properties. A huge number of diarylethenes have been synthesized so far. Analysis of the literature data shows that there are very worthy examples of diarylethenes developed by the Irie and Feringa groups, which can be the common starting material for a number of diarylethenes functionalized in hetaryl moieties. We refer to these structures as photochromic diarylethene precursors. These diarylethenes have proved to be very useful in the construction of functional molecules with desired properties. On the other hand, in our groups, we have elaborated on diarylethene precursors with modifiable ethene bridges. In this review, we have collected examples of such structures and their chemical modifications, leading to the improvement or fine‐tuning of photochromic switching. [ABSTRACT FROM AUTHOR]

Nine 1-[2-(1-substituted)ethyl-3-benzothienyl]-2-(2-methyl-3-benzothienyl)hexafluorocyclopentenes(4-substituted benzoyloxy, N-arylcarbamoyloxy, and aryloxycarbonyloxy) were synthesized. Upon UV irradiation, they showed diastereoselective photochromic ring closure.