The extracts from the leaves of Deschampsia antarctica É. Desv., Camelina sativa (L.) Crantz, and Camellia japonica L. plants, as well as from defatted Camelina sativa and Silybum marianum seedcakes were investigated as potential additives for improvement of biodiesel stability against oxidation. Composition of the extracts was studied by means of HPLC, and antioxidant properties were evaluated using the Folin-Ciocalteu assay and the DPPH test. The oxidation of biodiesel was monitored during the accelerated procedure at 43C, with the changes in the acid number of biodiesel samples being the criteria of this process. In spite of significant distinctions in the content of various phenolic compounds, all the extracts were found to possess high antioxidant activity and decelerate biodiesel oxidation by 9-26%. The data did not reveal a directly proportional relationship between the antioxidants content in the extract, on the one hand, and the enhancement in biodiesel stability, on the other hand; various extracts had different influence on the behaviour of biodiesel from rape and Camelina seed oils. The results obtained are consistent with the assumption that there is no universal stabilizer for different types of biodiesel and indicate the prospects on searching for novel antioxidants of natural origin to inhibit oxidative processes.

Novel supramolecular cation-anionic coordination compound (HPhen)4[(μ-O){Ge2(OH) (μ-Tart)2}2]·9H2O was synthesised and characterised by the X-ray, elemental, IR- and Hirshfeld surface analysis. It was established that original synthesis method and ability of 1,10-phenanthroline to be protonated promotes the formation of [(μ-O){Ge2(OH)(μ-Tart)2}2]4- anion. In this anion, dimeric fragments are connected by a bridging oxygen atom, and the coordination polyhedra around the germanium atoms adopt a distorted trigonal bipyramidal geometry. The cations HPhen+ serve as effective building blocks, strengthening the overall structure through classical hydrogen bonding and additional π-π stacking interactions. Biological screening of (HPhen)4[(μ-O){Ge2(OH) (μ-Tart)2}2]·9H2O demonstrated its remarkable enzyme-effector and antimicrobial activity. The compounds' efficacy can be attributed to the synergistic effects of the independent cations and anions, as well as the ability of protonated 1,10-phenanthroline to inhibit metal ions in enzymes and form stacking interactions with specific protein components. These characteristics make such compounds highly effective and promising antibacterial agents that minimize the risk of developing bacterial resistance.

In this paper the process of reagent desalination of mineralized mine waters was studied. The peculiarity of mine waters in many regions of Ukraine is that, along with hardness ions, they also contain sulphates in fairly high concentrations. Therefore, the task of desalination of mineralized waters consists in effective removal of sulphates along with softening of the solution. For effective purification of water from sulphates and hardness ions, 5/6 aluminum hydroxychloride (Al2(OH)5Cl) and sodium tetrahydroxoaluminate (Na[Al(OH)4]) were used during liming. A significant increase in efficiency of the treatment process was achieved when the solution was acidified with carbon dioxide after treatment with reagents. The directions of processing of the formed sediments as part of building materials have been determined. Complex processing of the generated waste in the process of water treatment allows creating a low-waste technology for the purification of mineralized water.

The in vivo experiments show that the adenosylcobalamin cofactor in glutamate mutase and methylmalonyl-CoA mutase processes lose its dimethylbenzimidazole axial ligand before starting the enzymatic processes. Complete active space self-consistent field geometry optimization of the vitamin B12 active forms plus substrates joint models have been performed. These joint models include the adenosylcobalamin cofactor, the carboxyl negative ion model of the studied processes’ active substrates, and the histidine molecule. Partial electronic density is transferred from the highest occupied substrate molecular orbitals to the lowest unoccupied antibonding molecular orbitals, which consist of corrin ring and dimethylbenzimidazole ligand common molecular orbitals during the multi-configurational self-consistent field molecular orbital mixing process. As a result, the Co-N axial bond is permanently elongated during the complete active space self-consistent field geometry optimization until its complete rupture and until the removal of the dimethylbenzimidazole ligand from the central cobalt atom and the corrin ring is complete. The Co-N bond cleavage in the adenosylcobalamin cofactors in the studied processes is running as no energy barrier process under the influence of their active substrates and histidine molecule.

The solvothermal reaction of zinc(II) nitrate with 1,2,3-benzenetricarboxylic acid (1,2,3-H3BTC) and 4,4ʹ-bis(imidazol-1-ylmethyl)biphenyl (BIBPh) produced a crystalline solid {[Zn3(BIBPh)3(BTC)2]∙H2O}n. The product has been structurally characterised and investigated by X-ray diffraction, IR and thermogravimetric methods. The polymer has a bidimentional structure and crystallizes in the P21/c space group of the monoclinic system with the following unit cell parameters: a= 14.8687(16), b= 36.915(4), c= 13.8378(16) (Å), β= 105.584(6)°. The asymmetric unit of the crystal structure contains three zinc(II) ions, three BIBPh ligands and two BTC3- monodentate ligands with all three deprotonated carboxylate groups that balance the overall charge. All zinc centers have similar coordination environment: each metal ion is four coordinated exhibiting a slightly distorted tetrahedral coordination, where two positions are occupied by oxygen atoms of the carboxylic acid and the other two by nitrogen atoms of imidazole subunits

The chemical composition, antioxidant and antimicrobial activity of propolis ethanolic and water-ethanolic extracts from the central zone of Moldova have been investigated by GC-MS and liquid chromatography. There were found 20 amino acids, of which the most abundant are glutamic acid, alanine, leucine and isoleucine. The main constituents of the alcoholic extract are pinocembrin, n-heptacosan and naringenin. The aqueous-alcoholic extract was characterized by the content of sakuranin, 4-methoxy sakuranetin, caryophylline oxide, isocaryophylline oxide, trans-longipinocarveol. The propolis extracts exhibited strong antioxidant (53.7 mg ascorbic acid eq./g extract or 113.4 mg Trolox eq./g extract and 87.5 mg ascorbic acid eq./g extract or 162 mg Trolox eq./g extract for ethanol, and water-ethanol extract, respectively) and antimicrobial activity (from 0.0055 up to 0.07%), suggesting their potential as natural agents for therapeutic use.

Nitrite ion, a characteristic pollutant, can be removed from water by reverse osmosis, distillation, or ion exchange resin. In this study, we removed it by using ZnO and CeO2 nanoparticles. First, zinc hydroxide and cerium hydroxide were prepared by the hydrothermal method and heated at 90°C to dry. Second, they were annealed at 400°C to produce nanoparticles of ZnO and CeO2, respectively. The obtained samples were characterized by X-ray diffraction to ascertain their structure and chemical composition. The surface morphology analysis of the nanoparticles was performed using scanning electron microscopy. Atomic force microscopy was employed to characterize the imaging surface and ascertain the surface roughness. The functional groups present at the surface of the nanoparticles were investigated using the Fourier transform infrared spectroscopy method. The optical properties of these particles were investigated using the UV-visible spectroscopy. Further, the produced nanoparticles were used to adsorb NO2- ions from aqueous solutions. The results showed that the nanoparticles which were heated at 90°C (hydroxide forms) presented a higher activity for nitrite ions removal than those that were heated at 400°C (oxide forms). This may be related to nitrite ions preferential adsorption to hydroxide forms rather than to oxide forms; in both cases (90°C and 400°C), zinc oxide nanoparticles presented higher nitrite removal activity.

Synthesis of novel tetranorlabdane compounds bearing 1,3,4-thiadiazole units and intermediary tetranorlabdane compounds with thiosemicarbazone fragment has been reported. The structures of the new synthesized compounds were confirmed using IR and 1H, 13C, and 15N NMR spectroscopy. The in vitro antifungal and antibacterial activities of the mentioned compounds have been evaluated. Results of this study have shown that the 1,3,4-thiadiazole-2-imine has excellent activity against tested strains of fungi and species of bacteria at minimum inhibitory concentration values of 0.125 and 2.5 μg/mL, respectively.

A heterometal assembled complex of tetrakis(μ-butanoato)diruthenium(II,III) and tetracyanidoaurate(III) [RuIIRuIII(n-C3H7COO)4AuIII(CN)4]n was synthesized and characterized by the elemental analysis and infrared spectroscopy. The single-crystal X-ray structure analysis revealed that the complex consists of zigzag chain molecules of alternating arrangement of the Ru2(n-C3H7COO)4+ and Au(CN)4– units with cis-bridging mode of the Au(CN)4– units. The temperature dependence of the magnetic susceptibility data (4.5—300 K) showed that the magnetic interaction between the dinuclear RuIIRuIII units (S= 3/2) is negligibly small with a zero-field splitting parameter D value of 60 cm-1.

This paper is dedicated to the synthesis of a copolymer with reducing properties obtained by functionalizing chitosan with quercetin and determining the antioxidant activity of the derivatives obtained depending on the molar mass of the polymer. For this purpose, low molecular weight chitosan was obtained by oxidizing commercial chitosan with hydrogen peroxide and further functionalization with quercetin by the covalent grafting method. The functionalization process was performed through the following steps: functionalization of chitosan with ethyl chloroformate to increase the reactivity of the amine group to the hydroxyl group of quercetin and grafting the quercetin molecule to the synthesized intermediate. The comparative antioxidant properties of the composite obtained by grafting technical chitosan with quercetin and by grafting low molecular weight chitosan were studied by the DPPH (2,2-diphenyl-1-picrylhydrazyl radical) method. The obtained results indicate that a decrease in the molecular weight of chitosan contributed to its grafting with quercetin. As a result, the functionalized polymer composite acquired a higher antioxidant activity and can be successfully used to inhibit the oxidation of various organic substrates in the cosmetic, food and pharmaceutical industries.