V. K. Ol’khovik

Synthesis and properties of luminophores derived from fluorinated biphenyls

A procedure was developed for the synthesis of dimethyl 2-fluoro-and 2,2′-difluorobiphenyl-4,4′-dicarboxylates. The latter were converted into fluorinated 4,4′-bis[(E)-2-(1,3-benzoxazol-2-yl)ethenyl]-and 4,4′-bis[5-(4-octyloxyphenyl)-1,3,4-oxadiazol-2-yl]biphenyls which showed strong luminescence in the crystalline state and in solution; their spectral properties were examined.

Synthesis and properties of 4,4′-bis[5-alkyl(aryl)benzoxazol-2-yl]-2-hydroxy(alkoxy)biphenyls

Synthesis of 2-hydroxy(methoxy)-4,4′-biphenyldicarboxylic acids was developed. Based on their reactions with o-aminophenols we prepared for the first time 4,4′-bis[5-alkyl(aryl)benzoxazol-2-yl]-2-hydroxy-(alkoxy)biphenyls, which might be of interest as luminescent dyes. Hydroxy compounds in a salt form possess abnormally high Stokes shift.

Synthesis, Antimicrobial and Antifungal Activity of Double Quaternary Ammonium Salts of Biphenyls

The synthetic methods for new 2-, 2,2′-, and 3-substituted 4,4′-bis(chloromethyl)biphenyls were developed. Quaternization of them with various amines resulted in a series of new double quaternary ammonium salts containing the biphenyl moiety. The majority of the obtained compounds have a pronounced antifungal and antibacterial activity against the Gram-positive bacteria.

Spectral and electroluminescent properties of divinylbiphenylyl

The results of studies of the spectral, luminescent, and electroluminescent characteristics of four linear divinylbiphenylyl derivatives are presented. All the compounds under study fluoresce effectively in solutions and thin films in the blue spectral range. For thermally vacuum-deposited films, it is possible that absorption and luminescence spectra change due to aggregate formation. The studied biphenyl derivatives can electroluminesce in simple single-layer devices with a low (4 V) threshold voltage.

One-pot method for the synthesis of sulfonated poly(1,3,4-oxadiazoles) based on 4,4’-oxydibenzoic acid

A series of new copolymers of poly(1,3,4-oxadiazole) that contain side protogenic sulfo groups are synthesized by the direct copolycondensation of terephthalic and 4,4’-oxydibenzoic acids and hydrazine sulfate in oleum. Variation in the polycondensation conditions makes it possible to synthesize copolymers containing phenylene moieties with either 4-sulfo-10,10-dioxophenoxatiine or 4,4’-oxybis(3-sulfophenyl) moieties or a combination of the three moieties. This approach permits easy control over the physicochemical properties of the copolymers and the amount of protogenic sulfo groups. It is shown that the introduction of sulfonated moieties into copolymer molecules makes it possible to obtain materials with high values of ionexchange capacity (1.5 mmol/g) and water absorption (110%), while the strength and thermal stability inherent in poly(p-phenylene 1,3,4-oxadiazoles) remain intact.

New high-tensile thermally stable copolymers of poly(p-phenylene-1,3,4-oxadiazole)

A one-stage method is developed for the synthesis of new irregular copolymers of poly(p-phenylene-1,3,4-oxadiazole), whose polymer chain contains a 5,5-dioxodibenzothiophenylene fragment. The polymer synthesis is performed through direct copolymerization of terephthalic acid, 5,5-dioxodibenzothiophen-3,7-dicarboxylic acid, and hydrazine sulfate in oleum at an elevated temperature. The introduction of 13.5–17% structural fragments of 5,5-dioxodibenzothiophene into a copolymer macromolecule makes it possible to improve the thermal stability and fire-resistance of fibers and films produced on their basis and to achieve a 30% increase in breaking strength and a fivefold greater breaking extension relative to those values for a homopolymer based on terephthalic acid.

Synthesis and properties of 2,7-phenylethenyl- and benzoxazol-2-ylethenyl N-ethylcarbazole derivatives

A number of new symmetrically and unsymmetrically substituted 2,7-phenylethenyl and benzoxazol-2-ylethenyl N-ethylcarbazole derivatives were synthesized by successive Wittig and Knoevenagel olefinations of 9-ethylcarbazole-2,7-dicarbaldehyde. The resulting compounds showed strong photoluminescence in the blue region. The spectral parameters of unsymmetrically substituted 9-ethylcarbazoles with a donor-donor-acceptor conjugation type are determined by intramolecular interaction in the donor-acceptor fragment.

Synthesis of new fungicidal biphenyl derivatives of 4,5-dichloroisothiazole-3-carboxylic acid

Methods have been developed for the synthesis of new 2,4,4′-substituted biphenyl derivatives containing 4,5-dichloroisothiazole-3-carboxamide and 4,5-dichloroisothiazole-3-carboxylate fragments. The synthesized compounds showed pronounced fungicidal activity.

Microwave-assisted synthesis of biphenyl-4,4′-dicarboxylic acid arylhydrazones in water medium

At the same time many condensation and addition reactions (for example, the Barbier and the Mannich types reactions, Diels–Alder cycloaddition and Knoevenagel condensation) occur also in aqueous media [5]. However, efficient performance of organic reactions in an aqueous media often requires complete dissolution of the reagents. For this purpose organic solvents are often added to the reaction mixture or the reactions are carried out at heating [6]. It is known [7] that the presence of water in the condensation of amines with carbonyl-containing organic compounds decreases the imines yield. Meanwhile, it has been shown [8] that the reaction of aromatic aldehydes and aliphatic amines in aqueous medium at 100°C afford the corresponding imine with a yield of 65–90%.

New luminescent dyes from the series of 1,3,7-substituted dibenzothiophene-5,5-diones

Preparation method was developed and a series of new linear polyconjugated compounds was obtained with (1,3-benzoxazol-2-yl)ethenyl, (5-oxo-2-phenyl-1,3-oxazolidine)methyl moieties in the positions 3, 7 of dibenzothiophene-5,5-dione frame and with peripheral alkoxy- and alkylamine substituents in the position 1. Compounds obtained possess a strong luminescence in solutions, in the solid state, and exhibit electroluminescent properties.