Russian Chemical Bulletin最新文献

The solvatochromic properties of 2-{5-[4-(diphenylamino)phenyl]thiophen-2-yl}-quinazolin-4(3H)-one and its (9H-carbazol-9-yl)phenyl analogue were studied. The difference between the dipole moments of the ground and excited states was calculated both theoretically (using density functional theory (DFT)) and experimentally (using the Lippert—Mataga, Bilot—Kawski polarity functions and the empirical solvent polarity parameter). The high values of these parameters indicate a considerable redistribution of electron density in the molecule upon photoexcitation and the formation of a more polar excited state. The effect of medium viscosity on photophysical properties was analyzed. A linear dependence of fluorescence quantum yield on medium viscosity was revealed for 2-[5-(4-diphenylaminophenyl)thiophen-2-yl]quinazolin-4(3H)-one, which is of interest for analytical studies.

The structure and thermal properties of the mesogenic luminophore 4-hexyloxy-4′-hexylsalicylideneaniline (1) were studied by X-ray diffraction and thermal analysis methods (differential scanning calorimetry combined with polarized light thermal microscopy). The asymmetric unit cell of the crystal of 1 contains two crystallographically independent molecules with significantly different conformations. Both molecules have a benzoid configuration of the bonds in the salicylidene moiety; the active proton was unambiguously located at the oxygen atom. On heating, compound 1 undergoes three crystal—smectic—nematic—isotropic phase transitions. Under UV irradiation, compound 1 exhibits photochromism and yellow luminescence, which is observed only in the mesophase. On cooling of the mesophase to the solid state transition temperature and below, the luminescence disappears. A comparative ability of representatives of the homologous series of 4-alkyloxy-4′-alkylsalicylideneanilines to show luminescence and its relationship with photochromism are discussed.

A metal-free oxidation of 1-benzyl-3,4-dihydroisoquinolines to 1-benzoyl-3,4-di-hydroisoquinolines was accomplished using dioxygen as an oxidant. This protocol provides a facile route for the efficient synthesis of isoquinoline alkaloids. Mechanistic investigation suggested that ionic pathway is the major route in the reaction and 1-[hydroxyperoxy(phenyl)-methyl]-6,7-dimethoxy-3,4-dihydroisoquinoline may be the key intermediate for the formation of the products.

A series of shielded o-benzoquinones combining the redox-active coordination center and photoswitchable aryldiazenyl moiety was synthesized. The stability of paramagnetic reduced forms of the synthesized o-quinones was confirmed by cyclic voltammetry. The electron density distribution in the corresponding radical anions was studied by EPR spectroscopy. The aryldiazenyl moiety of the functionalized ligands was shown to retain the ability for photoinduced reversible isomerization under visible and UV irradiation without destruction of the o-quinone fragment both in an organic solvent and solid polymer matrix.

A composite material with magnetic properties, which consists of nanosheets of graphene-like carbon nitride and iron oxide, that is, Fe₃O₄/g-C₃N₄, was synthesized. The nanocomposite was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetry. The obtained material was used as an adsorbent to remove phosphate anions from aqueous media. The influence of process parameters (pH, initial phosphate anion concentration, contact duration, adsorbent dose, and temperature) on its efficiency was investigated. The adsorption mechanism was examined based on the analysis of surface potentials under different acidity conditions. A comparative study of the applicability of the Langmuir and Freundlich adsorption models for the description of experimental phosphate adsorption isotherms was carried out. The thermodynamic parameters of the process were calculated. The highly stable material can be easily removed from aqueous solutions using an external magnet after the completion of the adsorption experiments and reused in five to six cycles while continuing to demonstrate a high adsorption efficiency.

By reacting 2-aryl-1-(vinylsulfonyl)pyrrolidine with various diamines, new taurine derivatives containing pyrrolidine and diamine fragments were obtained. The proposed method affords taurine derivatives under mild conditions and in high yields. The structures of the products were confirmed by ¹H and ¹³C NMR and IR spectroscopy; the compositions were verified by elemental analysis.

Two efficient synthetic procedures for charge-compensated cobalt bis(dicarbollide) conjugates with 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY), in which the boron cluster is attached to the meso position of the dipyrrylmethene moiety were developed: (1) through the nucleophilic opening of cyclic oxonium derivatives of cobalt bis(dicarbollide) by BODIPYs modified with the benzyldimethylamino group; (2) through the synthesis of cobalt bis(dicarbollide) aldehydes followed by their condensation with 2,4-dimethylpyrrole, oxidation, and complexation with BF₃•Et₂O. The study of the optical properties of the BODIPY derivative with the benzyldimethylamino substituent and its boron-containing conjugates demonstrated that the attachment of the boron cluster enhances the fluorescence of BODIPY. Therefore, the synthesized compounds can be used for further biological assays as fluorescent boron neutron capture therapy agents to determine the distribution of boron in the body.

Alkylation of aniline with bicyclic monoterpenes, namely, (−)-β- and (+)-α-pinenes, in the presence of various catalysts was studied. Aluminum-containing catalysts were found to be efficient for the synthesis of N-substituted anilines with the p-menthene and bornyl structure of the terpene substituent. The reactions of α-pinene with an excess of aniline gave rise to substituted tetrahydroquinolines. Using various test systems, it was shown that the antioxidant activity of terpenylanilines significantly depends on the isomerism of the terpene fragment. N-Bornylaniline was found to be more active than N-alkylaniline with a p-menthene fragment, which makes it of interest for further, more detailed study as a new highly active antioxidant for technical and biomedicinal applications.

This review summarizes the recent advances in the oxidative cleavage of the furan ring as a structural component of complex molecules. Depending on the selected oxidizing agent and the degree of substitution of the furan ring, this approach provides saturated and unsaturated γ-dicarbonyl compounds, β-aryl(hetaryl) enones, enals or enoates, pyrrolin-2-ones and pyrrolidin-3-ones, γ-butyrolactones, and carbonyl alkynes. The review covers literature published from 2015 to 2025.

Creation of bioreceptor layers with predetermined morphology and functionality on the surface of electrolyte-gated organic field-effect transistors (EGOFETs) is a challenge for researchers working on the development of liquid biosensors. In this work, a biotin-containing receptor layer was formed directly on the surface of organic semiconductor (component of an EGOFET device) using the azide-alkyne cycloaddition reaction proceeding by the click mechanism. A new alkyne-functionalized [1]benzothieno[3,2-b][1]-benzothiophene derivative allows one to carry out the Cu^I-catalyzed click reaction on the EGOFET surface. The effect of the content of the alkyne derivative in the organic semiconductor on the morphology and functionality of the resulting bioreceptor layer is assessed. Subsequent modification of the biotin fragments with streptavidin and a DNA aptamer as a selective receptor allowed one to create a biosensor that detects the influenza A virus at a concentration of 3 • 10⁶ virus particles mL⁻¹, which corresponds to the sensitivity of the antibody-based test strips.