V. A. Barachevskii

Synthesis and properties of dihetaryl-substituted furanones. Synthesis of photochromic dithienylethenes containing a furanone bridging fragment

The reaction of 2,5-dimethylthiophen-3-ylacetic acid with 2,5-dimethylthiophen-3-ylacetyl chloride gave 3,4-bis(2,5-dimethylthiophen-3-yl)furan-2(5H)-one which was converted into a series of 5-methylidene and 5-arylmethylidene derivatives.

Spectral-kinetic evidence of interaction of photochromic diarylethenes with silver nanoparticles

Spectral-kinetic investigations of the photochromism of some diarylethenes with sulfur-containing substituents in dimethylsulfoxide solutions with and without silver nanoparticles are performed. It is shown that silver nanoparticles chemically interact with diarylethene molecules, which is manifested in a change in the spectral and kinetic characteristics and photodegradation efficiency.

Photochromic silicon polymers based on 1,2-dihetarylethenes

Silicon-containing three-dimensional polymers (coatings) exhibiting photochromic effects have been synthesized on the basis of 1,2-dihetarylethenes with N-hydroxyethyl and N-allyl groups, polysiloxanes, and polysilazanes. Irradiation of the coatings at ∼380 and >500 nm induces reversible transitions between colorless open and colored cyclic forms of the polymers. The efficiency of photochromic transformations in the coatings is lower than that in the initial dihetarylethenes and is dependent on the structure of the polymer matrix and the content of photochromic fragments.

Synthesis of 4-hetaryl-5,6-(2,5-dimethyl-3-thienyl)-2-phenyl-4h-thiazines and investigation of their photochromism

The polar [4+2] cycloaddition reaction of 1,2-bis(2,5-dimethyl-3-thienyl)acetylene with thiobenzamide and certain aldehydes of the thiophene and furan series catalyzed by boron trifluoride etherate gives the corresponding 4-hetaryl-5,6-di(2,5-dimethyl-3-thienyl)-2-phenyl-4H-1,3-thiazines. The photochromic properties of the products have been studied.

New photochromic polymers

New photochromic polymers were synthesized by quaternization of amino groups of N-methyldiethanolamine polyterephthalate with a mixture of bis(2,5-dimethyl-4-chloromethyl-3-thienyl)-1,3-dioxol-2-one and p-or m-xylylene dichloride. The spectral-kinetic studies of coatings based on the obtained polymers showed that these coatings have photochromic properties, the efficiency of which decreases with an increase in the sample thickness.

Photochromic fulgimide-containing silicones immobilized on the surface of polyarylate

Photochromic coatings immobilized on the surface of polyarylate films are prepared on the basis of fulgimides, oligosiloxanes, and oligosilazanes. The irradiation of coatings with UV light at a wavelength of @380 nm and visible light at a wavelength above 500 nm results in photoinduced reversible transitions between open and colored cyclic forms. Photochromic polymer films with the most acceptable characteristics are obtained from fulgimide-containing oligoaminosiloxane and oligovinyldimethylsilazane. It is found that the photosensitivity of these films is higher than that of similar films based on 1,2-dihetarylethenes.

Synthesis and photochemical properties of phenoxy derivatives of anthra[2,3- b ]furan-5,10-dione

Nucleophilic replacement of the hydroxy groups in ethyl 4,11-dihydroxy-2-methyl-5,10-dioxo-5,10-dihydroanthra[2,3-b]furan-3-carboxylate by chlorine upon treatment with phosphorus acid chlorides gave the corresponding 4(11)-chloro derivatives which were converted into photochromic ethyl 4(11)-phenoxy-2-methyl-5,10-dioxo-5,10-dihydroanthra[2,3-b]furan-3-carboxylates. Photoinduced decomposition of the latter leads to the formation of phenol and fluorescent hydroxyanthra[2,3-b]furandiones.

Synthesis and photophysical properties of photochromic phenyl-substituted polyphenylenes with main-chain azobenzene fragments

New photochromic phenyl-substituted polyphenylenes containing azobenzene fragments in the backbone have been synthesized by the interaction of diacetylenes with bis(cyclopentadienones) via the Diels-Alder reaction. The polymers thus prepared exhibit the photochromic behavior and combine solubility in common organic solvents with high viscosity and thermal characteristics.

Spectral indications of interaction of functionalized photochromic compounds with Ag and Au nanoparticles

A comparative investigation of the photochromism of photochromic spiropyrans, spirooxazines, and diarylethenes in solutions and in solid-phase films in the absence and in the presence of silver and gold nanoparticles was undertaken by a kinetic spectral method. On the basis of the experimental data it was concluded that hybrid photochromic nanoparticles of the core–shell type can be obtained as a result of chemical reaction of functionalized molecules with the nanoparticles of noble metals.

Spectrokinetic study of photochromic transformations of spironaphthopyran metal complexes

Five new metal complexes of 3,3-bis(phenyl)-5-hydroxy-3H-naphtho[2,1-b]pyran with the Pb2+, Zn2+, Ni2+, UO22+, and Tl2+ ions were synthesized. A comparative spectrokinetic study of photochromic transformations of these complexes and uncoordinated naphthopyran was performed. It was shown that the metal complexes exhibit photochromism properties similar to the reversible phototransformations of the precursor. The differences found in the photochromic transformations are explained by the influence of the metal atom on the conjugated bonds and steric changes in the molecule of the complexes.