V. A. Barachevsky

Photochromism of Thienyl-Containing Dihetarylethenes with Five-Membered Cyclic Bridges

ABSTRACT Spectral-kinetic characteristics of a number of new photochromic dihetaryethenes with different five–membered cyclic bridges are measured and discussed. It was shown that these characteristics depend on a bridge structure as well as a nature of substituents in the thienyl fragments.

A comparative study of the spectral and kinetic properties of photochromic dihetarylethenes based on maleic anhydride and maleimide

A comparative spectral-kinetic study of the photochromism of a number of new thermally irreversible 1,2-diarylethenes, considered as possible candidates for 3D optical data storage, is performed. The diarylethenes studied contain as bridges either maleic anhydride or maleimide derivatives. A relation between the structure of the bridges and substituents of these compounds and their photochromic properties is established.

Photochromic and irreversible photofluorescent organic materials for 3D bitwise optical memory

This paper presents latest own results in the development of reversible photochromic and irreversible photofluorescent polymer systems providing fabrication of multilayer recording media for 3D optical memory with super high information capacity. It was shown that synthesized thermal irreversible photochromic diarylethenes into plastic binders allow to prepare photochromic polymer layers providing nondestructive refractive read-out of optical information. These photochromic polymer layers were used for preparation of six-layer recording media tested with the positive results using the framed optical device. This device imitated layer-by-layer writing, erasure and read-out of optical signals. Experimental evidences for making photochromic polymer layers based on a mixture of photochromic diarylethene and dye — phosphor with nondestructive fluorescent read-out are presented too. Polymer systems based on light-sensitive chromones manifest an irreversible photochemical transformations of these non-fluorescing compounds into the fluorescent products under UV irradiation. Received results open perspectives for making multilayer optical discs for bitwise working (based on photochromic systems) and archival (based on irreversible photofluorescent systems) optical memory with information capacity more 1 TB.

Synthesis and structure of indoline spiropyrans of the coumarin series

New indoline spiropyrans of the coumarin series were synthesized by the condensation of indoline and hydroxyformylcoumarin derivatives. Spiropyrans, viz., derivatives of 8-formyl-7-hydroxy-4-methylcoumarin and 5-formyl-6-hydroxy-4-methylcoumarin, under irradiation are transformed into open forms, which are recyclized in the dark. The compounds formed by the condensation of the indoline derivatives with 3-formyl-4-hydroxycoumarin have an open structure of the merocyanine dyes and are transformed into spiro forms neither in the dark nor under irradiation with the visible light.

Spectral-kinetic study of phototransformations of new 3-acyl-2-hetarylchromones

Spectral-kinetic and fluorescent properties of 16 new photosensitive compounds of the 2-furyl- and 2-thienyl-3-acylchromone classes, the initial nonluminescent forms of which undergo irreversible phototransformations into fluorescent products, are considered on the basis of their structure and properties responsible for the possibility of their application as photosensitive components of recording media for archive optical disks.

Light-sensitive organic systems and multilayer polymer structures for optical recording media

This paper presents latest own results in the development of reversible photochromic and irreversible photofluorescent polymer systems providing fabrication of multilayer recording media for 3D optical memory with super high information capacity. It was shown that synthesized thermal irreversible photochromic diarylethenes into plastic binders allow to prepare photochromic polymer layers providing nondestructive refractive read-out of optical information. These photochromic polymer layers were used for preparation of six-layer recording media tested with the positive results using the framed optical device. This device imitated layer-by-layer writing, erasure and read-out of optical signals. Experimental evidences for making photochromic polymer layers based on a mixture of photochromic diarylethene and dye - phosphor with nondestructive fluorescent read-out are presented too. Polymer systems based on light-sensitive chromones manifest an irreversible photochemical transformations of these non-fluorescing compounds into the fluorescent products under UV irradiation. Received results open perspectives for making multilayer optical discs for bitwise working (based on photochromic systems) and archival (based on irreversible photofluorescent systems) optical memory with information capacity more 1 TB.

Synthesis of spiropyran analogues of retinal and study of their interaction with bacterioopsin from Halobacterium salinarum

The synthesis of a series of retinal analogues containing the spiropyran moiety instead of trimethylcyclohexene ring was proposed. The interaction of the resulting retinal analogues with bacterioopsin from apomembranes of Halobacterium salinarum and the spectral characteristics of the new pigments were studied.

New bistable organic photochromic compounds for bitwise working optical memory

The results of our spectral and kinetic studies for some photochromic compounds (58 diarylethenes and 9 fulgimides) are presented. Aiming at targeted synthesis of new photochromic compounds, the structure-photochromic behavior relationship (SPBR) for the synthesized compounds has been analyzed. The perspectives for application of these compounds in development of recording media for use in optical memory devices are outlined.

Photochromic and Cation-Binding Properties of New Crowned Spiropyrans

ABSTRACT Spectral properties of new crowned spiropyrans and their cationic complexes are described.

A comparative study of the spectral and kinetic properties of photochromic derivatives of perfluorocyclopentene diarylethenes

A comparative spectral-kinetic study of the photochromism of a series of synthesized thienyl derivatives of perfluorocyclopentene dihetarylethenes is performed. A relation between the photochromic properties of these compounds (the absorption spectra of the initial and photoinduced forms, the photosensitivity, the interconversion constants of both forms, and the photodegradation) and their structure is established. For some compounds experiencing reversible and irreversible phototransformations, photoinduced fluorescence was observed. The data obtained give grounds to suggest that the compounds synthesized can be used in developing recording media for two-photon 3D main and archival storage.