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Документ Determination of trace elements (Cr, AI, Pb) by atomic absorption in natural water of Kyiv(2014) Polumbryk, Maksim; Ishchenko, Vera; Polumbryk, OlegThe control of microelements in water is a one of the most important factor of the humans health in urbanized cities. ETAAS method with chemical modifiers has been used in drinking water analysis.Документ Antioxidants in food systems. Mechanism of action(2013) Polumbryk, Maksim; Ivanov, Sergey; Polumbryk, OlegThe mechanisms of action of natural and synthetic antioxidants in food systems including lipids, proteins and carbohydrates have been discussed. It is essentially important and may predict the antioxidants effectiveness in the processes of food storage. The main benefits of industrial antioxidant utilization were considered. The most attention was given to the antioxidants mixtures and most effective synergists.Документ Electronic and steric structure “Quasi-verdazyls.” I. Phosphaverdazyl and its leuco base(1984) Nesterenko, A.; Polumbryk, Oleg; Markovskii, LeonidBy the PNDO method in an spd basis, with complete optimization of geometry, the electronic and steric structure has been calculated for different conformers of a model phosphaverdazyl and its leuco base. The results are consistent with the interpretation given previously for the ESR spectra of phosphaverdazyls. Features of electronic structure are judged in terms of their influence on the physicochemical properties and reactivity of phosphatetrazines.Документ Electronic structures and reactivities of derivatives of 1,4-dihydropyridines. 1. 1-methyl-3-carbamidopyridinyl radical and 1-methyl-3-carbamidopyridinium cation(1987) Nesterenko, A.; Buryak, Nadezhda; Polumbryk, Oleg; Yasnikov, A.The physicochemical properties and electronic and three-dimensional structures of the products of transformations of 1-methyl-1,4-dihydronicotinamide were calculated within the MINDO/3 approximation. The problems associated with their reactivities in reactions involving electron and hydrogen-atom transfer, as well as the problems of “hydride” transfer in chemical reactions, are discussed.Документ Synthesis of 5-nitro-N,N-diphenylhydrazinopyrimidines and investigation of their free radicals(1980) Boldyrev, I. V.; Polumbryk, Oleg; Markovskii, Leonid; Cherkasov, V. M.A number of 5-nitro-N,N-diphenylhydrazinopyrimidines were synthesized. Free radicals were obtaines by oxidation of these compounds with PbO2. The stabilities of 5-nitro-4-pyrimidinylhydrazyl radicals are close to the stability of the α,α-diphenyl--2,4-dinitrophenylhydrazyl radical. The structures of the compounds obtained were confirmed by the UV, IR, PMR and EPR spectra.Документ Verdazyl radicals with perfluorphenyl rings(1978) Polumbryk, Oleg; Ryabokon, Ivan; Markovskii, LeonidNew formazans, tetrazines, and verdazyl radicals containing pentafluorphenyl residues were synthesizedon the basis of the reaction of perfluorphenylhydrazones with benzenediazonium salts. The stabilities of the free radicals obtained considerably exceed stability of the diphenylpicrylhydrazyl radical.Документ Quantum-chemical investigation of spatial and electronic structure of verdazyl and its derivatives(1979) Markovskii, Leonid; Polumbryk, Oleg; Nesterenko, A.The unrestricted HF method in the INDO approximation with optimized geometry was used to describe the electronic structure of the hetero-ring of verdazyl and the derivatives of the latter. The results obtained are in good agreement with the experimental EPR spectra of triphenylverdazyl radical and its dipole moment. These data may be a basis for understanding and predicting the chemical properties and reactivity and its derivatives.Документ Polarographic investigation of donor-acceptor properties of triphenylverdazyls in propylene carbonate(1975) Polumbryk, Oleg; Dvorko, G.; Vasil'kevich, N.; Kuznetsov, V. A.Вивчено полярографічне окиснення і відновлення заміщених трифенілвердазильних радикалів та ДФПГ в пропіленкарбонаті при 25 °С. Отримані дані дозволяють охарактеризувати донорно-акцепторні властивості і вплив на них замісників у С-фенільному кільці вердазильних радикалів.Изучено полярографическое окисление и восстановление замещенных трифенилвердазильных радикалов и ДФПГ в пропиленкарбонате при 25 °С. Полученные данные позволили охарактеризовать донорно-акцепторные свойства и влияние на них заместителя в С-фенильном кольце вердазильных радикалов.The polarographic oxidation and reduction of the substituted triphenylverdazyl radicals and DPPH at 25 °С has been investigated. The donor-acceptor properties of those radials and influence of substituent on the C-ring were characterized on basis of these data.