Vol 93, No 1 (2023)

The synthesis of esters of some carboxylic acids by the method of oxidative esterification was carried out. It was shown that the proposed method allows the selective esterification of carboxylic acids with hindered carboxyl groups. It was found that the synthesized esters have anti-aggregation activity at the level of acetylsalicylic acid.

The hydrolysis of substituted 3-(3-cyanothiophen-2-yl)imino-3 H -furan-2-ones was studied. It was found that the reaction proceeds with the opening of the furan ring and the formation of the corresponding 4-oxo-2-(3-cyanothiophen-2-yl)aminobut-2-enoic acids. The antibacterial activity of the obtained compounds against Staph ylococcus aureus , Escherichia coli and Candida albicans was studied.

Three-component Biginelli reaction of ethyl 4-(2,4-dioxo-4-phenylbutanamido)benzoate, aromatic aldehyde and thiourea in acetic acid in the presence of sodium acetate led to the formation of ethyl 4-(6-aryl-5-benzoyl4-hydroxy-2-thioxohexahydropyrimidine-4-carboxamido)benzoates. Structure of the obtained compounds was established by IR, ¹H NMR, ¹³C spectroscopy methods.

2,3-Dihydrothiazolo[2,3- b ]thiazolium iodides and bromide were obtained for the first time by the cyclization of corresponding metallyl- and propinylsulfanyl derivatives of 1,3-thiazole with iodine and bromine in dichloromethane without heating and the use of strong acids. The structure of the obtained compounds was studied by ¹H, ¹³C{¹H} NMR spectroscopy. Structure of the 3-iodomethyl-3,5-dimethyl-2,3-dihydrothiazolo[2,3- b ][1,3]thiazolium heterocyclic system is characterized by the X-ray analysis. The bonding in the heterocyclic system and non-covalent cation-anion interactions are analyzed on the basis of quantum chemical calculations with periodic boundary conditions; I···S chalcogen bond is discussed.

The photocatalytic properties of new representatives of the family of metal-free catalysts, 10-hydro-9-phenylacridine, 10-methyl-9-phenylacridinium chloride, and 10-phenyl-9-phenylacridinium chloride, were studied with respect to the reaction of molecular hydrogen generation in the presence of acids of different strength (HClO₄, CH₃SO₃H, and CF₃COOH) and reducing agents ([Bu₄N]Cl, [Bu₄N]Br, and [Bu₄N]I). It was found that the strength of acids (p K _a) and the nature of the reducing agent ( E ₀) significantly affect the efficiency, i.e. turnover frequency (TOF), of the process under study. The amount of formed molecular hydrogen reaches its maximum in the case of the combination HClO₄ and [Bu₄N]I, characterized by minimal p K _a and E₀ values, respectively. The influence of the nature of substituents at the nitrogen atom in 9-phenylacridine on the efficiency of the molecular hydrogen production was analyzed. It was shown that the limiting stage of the process is the protonation of the formed radical.

The product of 3-formyl-2-quinolone condensation with trimethylammonium chloride acethydrazide, (H₂L⁺)Сl^- hydrazone, was synthesized. Complexes of Zn(II) and Cu(II), [M(HL)OCH₃]ClO₄, with a distorted square-planar strucrure of coordination sites and asymmetric chelate сomplexes of Mn(II), Ni(II), and Co(II), [M(HL) (H₂L)]·(ClO₄)₃, of pseudo-octahedral structure were obtained on its basis. The protistocidal, antibacterial, and fungistatic activities of the synthesized compounds were studied.

A series of cyclometallated platinum(II) complexes [Pt(ppy){CNAr}₂]X with two isocyanide ligands (Hppy = 2-phenylpyridine, Ar = C₆H₂-2,4,6-Me₃, C₆H₃-2-Cl-6-Me , C₆H₃-2,6-Cl₂, C₆H₄-4-NMe₂, C₆H₄-4-Me, C₆H₄ 4-Cl, C₆H₄-4-Br, C₆H₄-4-I, C₆H₄-4-CF₃, C₆H₄-3-CF₃; X = BF₄, OTf) was synthesized by the reaction of the [{Pt(ppy)Cl}₂] dimer with isocyanides (yield 52-70%). The structure of the resulting complexes was determined using mass spectrometry, ¹H, ¹³C{¹H}, ¹⁹⁵Pt{¹H}, ¹H-¹H COSY, ¹H-¹H NOESY, ¹H-¹³C HSQC, and ¹H-¹³C HMBC NMR spectroscopy in solution and solid-state CP/MAS ¹³C and ¹⁹⁵Pt NMR spectroscopy, IR spectroscopy and X-ray diffraction analysis in the solid phase. The photophysical properties of the obtained complexes in the solid phase and the mechanochromic luminescence behavior were studied. In the solid phase, all synthesized compounds phosphoresce in the green or orange range of visible light, while photoluminescence quantum yields reach 26%. Green phosphors exhibit a reversible mechanochromic luminescence change achieved by mechanical grinding (green to orange) and solvent adsorption (orange to green).

Solid solutions of lanthanum manganites with perovskite structure containing calcium and gadolinium atoms were studied by the method of magnetic dilution. The obtained magnetic characteristics and the character of their temperature changes point to a clustering of magnetic atoms in the perovskite structure. A comparison of the solid solutions under study with La_{1- y} Gd _y AlO_{3 testifies for gadolinium atoms taking part in the exchange interactions in the La1-0.397 х Gd0.067 х Ca0.33 х Mn х Al1- х O3 solid solutions.}

The synthesis of CoNPs cobalt nanoparticles by the method of polyol- process was proposed, which consists in a high-temperature synthesis of polymer-stabilized metal nanoparticles in a matrix of a fourth-generation hyperbranched polyester polyol. Branched polyester polyol acts as both a reducing agent and a stabilizer at the same time. It has been found that the reduction of the precursor CoCl₂ with a hyperbranched polyester polyol occurs at 210°C. The introduction of NaOH into the reaction mixture makes it possible to lower the synthesis temperature by 50°C and leads to a change in the mechanism of in situ ripening CoNPs from the digestive mechanism to direct Ostwald ripening.