I. E. Mikhailov

Synthesis, structure, and spectral luminescent properties of novel 1,2,4-triazole derivatives containing benzthiazole group

Novel derivatives of 1,2,4-triazol with benzthiazole fragment have been prepared, including Cu(II) and Be complexes. Their structure and spectral luminescent properties have been investigated. With ohydroxyphenylbenzthiazolyl-1,2,4-triazole as an example, the density functional theory has been applied to find the stable conformers with different structures of coordination nodes, stabilized by intramolecular hydrogen bonds between hydroxyl group hydrogen and either triazole of benzthiazole nitrogen.

Synthesis, structure, and luminescent properties of 2-[2-(9-anthryl)vinyl]quinolines

Previously unknown 2-[2-(9-anthryl)vinyl]quinolin-8-ol and 2-[2-(9-anthryl)vinyl]-8-methoxyquinoline were synthesized by condensation of 8-hydroxy(methoxy)-2-methylquinoline with 9-anthraldehyde in acetic anhydride, as well as by the Wittig reaction. The product structure was determined on the basis of their 1H NMR, IR, UV, and mass spectra and quantum-chemical calculations. 2-[2-(9-Anthryl)vinyl]-8-methoxyquinoline showed luminescence with a quantum yield φ of 0.25, which was considerably higher than that of its 8-hydroxy analog (φ = 0.067).

Synthesis and luminescence properties of 2-(2-benzoyloxyphenyl)-5-aryl-1,3,4-oxadiazoles

Bidentate ligand systems based on 2-hydroxyphenyloxadiazole attract strong interest due to application of metal complexes derived therefrom in photoand electroluminescent devices as blue-emitting chromophores, as well as electron-transporting materials that improve charge transfer balance in organic light-emitting diodes (OLEDs) [1, 2]. In addition, organic luminophores based on diphenyloxadiazoles exhibit an anomalously high Stokes shift (ASS), which favors increase in the light yield as a result of reduced self-absorption and minimizes liminophore photodegradation [3].

Reactions of hydroxyphenyl-substituted 1,2,4-triazoles with electrophylic reagents

Reactions of hydroxyphenyl substituted 1,2,4-triazoles with various electrophylic reagents were studied. Despite of the presence of several nucleophilic centers in the molecule, the reactions were shown to proceed regioselectively, with the formation of N-substituted 3-(2-hydroxyphenyl)-1,2,4-triazoles. As a result of the reactions of alkylation, tosylation, sulfoamination and aminomethylation by Mannich reaction earlier unknown potential biologically active N-derivatives of 1,2,4-triazole were obtained.

Synthesis and spectral-luminescence properties of 2-[2-(pyridin-4-yl)vinyl]quinolines

Condensation of 2-methylquinolines with 4-pyridinecarboxaldehyde in acetic acid anhydride has yielded 2-styryl-8-hydroxyquinoline along with its methyl and benzyl derivatives. Tosylation of 2-styryl-8-hydroxyquinoline has led to the corresponding p-toluenesulfonyloxy derivative. All the obtained compounds have revealed blue-green luminescence (λmax = 438–512 nm); however, only alkyl derivatives of 2-styryl-8-hydroxyquinoline possessed the high quantum yield (φ = 0.16–0.41).

Synthesis and luminescent properties of 2-[2′-acyl(benzoyl)oxyphenyl]-5-(4″-nonylphenyl)-1,3,4-oxadiazole

a Southern Scientific Center, Russian Academy of Sciences, ul. Chekhova 41, Rostov-on-Don, 344006 Russia e-mail: mikhail@ipoc.rsu.ru b Southern Federal University, Rostov-on-Don, Russia c Institute of Arid Zones, Southern Scientific Centre, Russian Academy of Sciences, Rostov-on-Don, Russia d Scientific Research Institute of Physical and Organic Chemistry, Southern Federal University, Rostov-on-Don, Russia

Absorption and luminescence spectra of 5-aryl-3-methyl-1,2,4-oxadiazoles and their chelate complexes with Zinc(II) and copper(II)

Abstract5-(2-Hydroxyphenyl)-3-methyl-1,2,4-oxadiazole and its O-methyl and O-acyl derivatives, as well as zinc(II) and copper(II) chelates, were synthesized. All these compounds showed luminescence with the emission maxima ranging from λ = 332 to 490 nm, but only 5-(2-methoxyphenyl)- and 5-(2-acetoxyphenyl)-3-methyl-1,2,4-oxadiazoles and zinc(II) complex of 5-(2-hydroxyphenyl)-3-methyl-1,2,4-oxadiazole were characterized by high luminescence quantum yield (φ = 0.308–0.452, 0.089–0.153, and 0.115–0.334, respectively). Stable conformers of 5-(2-hydroxyphenyl)-3-methyl-1,2,4-oxadiazole with different structures of the coordination entity were identified by DFT quantum chemical calculations.

Synthesis and Structure of a New Polydentate 8-Hydroxyquinoline Ligand System with a 1,3-Tropolone Fragment at Position 2 in the Quinoline Ring

An original three-step method has been developed for the synthesis of a new polydentate 8-hydroxyquinoline ligand system with a 1,3-tropolone fragment at position 2 of the quinoline ring. X-ray diffraction structural analysis, 1H and 13C NMR spectroscopy, and quantum-chemical calculations showed that this ligand exists in the NH-tautomeric form with the phenolic hydroxyl group in the exo position of the quinoline ring.

Synthesis of 1-(benzothiazol-2-yl)-5-(o-hydroxyphenyl)-1H-1,2,4-triazoles

Recyclization of 4-oxo-1,3-benzoxazinium perchlorates by the action of benzothiazolylhydrazine gave previously unknown benzothiazolyl-substituted 1,2,4-triazoles that attract interest as potential biologically active substances. The structure of the isolated compounds was determined on the basis of their IR and 1H and 13C NMR spectra.

Spectral luminescent properties of 2-(2-hydroxyphenyl)-5-methyl-1,3,4-oxadiazole and its acetyl(benzoyl)oxy derivatives

1,3,4-Oxadiazoles possess high and various pharmaceutical and biological activity [1], high intensive luminescence in the shortwave region of visual spectrum and good electron-conducting properties [2], they are thermally and chemically stable compounds that facilitates their wide application in different fields of agricultural [3] and medicinal chemistry [4], at obtaining highly effective organic and metal complex fluorescence dyes [5, 6], and also in production of modern electrooptical devices [7]. In this connection extending the range of such compounds and investigation of their spectral luminescent properties is an actual issue.