Publications by authors named "Pavel Tkachenko"

The first fully inorganic Pt(IV) carbonato-complex -[Pt(CO)(OH)] with a {PtO} coordination sphere was isolated as the (MeN)[Pt(CO)(OH)] () salt. The compound was characterized using single-crystal and powder X-ray diffraction, Raman spectroscopy, infrared spectroscopy (FTIR), electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance spectroscopy (NMR), and thermogravimetric analysis (TG). Density functional theory (DFT) calculations were also performed to analyze the spectral features of the complex.

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A combination of multinuclear nuclear magnetic resonance spectroscopy and theoretical calculation based on density functional theory was used for a speciation study of Pt in solutions prepared either by the interaction of [Pt(OH)] with gaseous CO in an alkaline solution of platinum(IV) hydroxide ([Pt(OH)(HO)]) or by the dissolution of [Pt(OH)(HO)] in an aqueous KHCO solution. The formed solutions contained coexisting Pt(IV) carbonato complexes with κ- and κ-coordination modes. The gradual condensation of mononuclear Pt species in such bicarbonate solutions resulted in the formation of PtO nanoparticles aggregating into a solid precipitate on prolonged aging.

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The systematic study of the platinum speciation in sulfuric acid solutions of platinum (IV) hydroxide {[Pt(OH)(HO)], HHPA} was performed with the use of a combination of methods. Depending on the prevailing Pt form, the three regions of HSO concentration were marked: (1) up to 3 M HSO forms unstable solutions gradually generating the PtO·HO particles; (2) 4-12 M HSO, where the series of mononuclear aqua-sulfato complexes ([Pt(SO)(HO)], where = 0···4) dominate; and (3) 12 M and above, where, along with [Pt(SO)(HO)] species, the polynuclear Pt(IV) species and complexes with a bidentate coordination mode of the sulfato ligand are formed. For the first time, the salts of the aqua-hydroxo Pt(IV) cation [Pt(OH)(HO)]SO (triclinic and monoclinic phases) were isolated and studied with a combination of methods, including the single-crystal X-ray diffraction.

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The paper presents the experimental research findings for the integral characteristics of processes developing when two-phase liquid droplets collide in a heated gas medium. The experiments were conducted in a closed heat exchange chamber space filled with air. The gas medium was heated to 400-500 °C by an induction system.

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Article Synopsis
  • * The study analyzed 5 cases from 2007 to 2019 using histological and immunohistochemical methods to identify the clinical and morphological features of these tumours.
  • * Benign Brenner tumours were more common than malignant ones, with symptoms differing; benign cases presented as abdominal pain, while malignant cases showed more severe symptoms, including abdominal enlargement and bowel obstruction.
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