L. I. Demina

Orthophosphoric Acid-;N,N-Dimethylformamide System: IR Study

Interactions in the orthophosphoric acid (H3PO4)-;N,N-dimethylformamide (DMF) system are studied by IR Fourier spectroscopy. A mechanism of interaction between the H3PO4 and DMF molecules was proposed on the basis of the results and the earlier reported viscosimetry data for this system.

The effect of graphene oxide (GO) on biomineralization and solubility of calcium hydroxyapatite (HA)

Interaction between GO and the counterpart of the bone tissue, calcium hydroxyapatite Ca10(PO4)6(OH)2 (HA), is modeled in the course of synthesis of nanosize composite materials (CMs) based on graphene oxide (GO) and biocompatible HA with a GO content of 0.1, 1.0, 2.0, and 5.0 wt % GO from aqueous solutions in the system of Ca(OH)2–H3PO4–GO–H2O under native conditions (37°C). The effect of CM composition on the size and morphology of HA nanocrystals (HA NCs) is determined using the methods of physico-chemical analysis (chemical, XRD, IRS, DTA, TDG, SEM, TEM). The solubility of HA NC CMs by Ca2+ ions in distilled water is determined under in vitro conditions, and the possible results of interaction between GO and native calcified tissues are analyzed.

Cation-promoted supramolecular assembly of bivalent metal tetra-15-crown-5-phthalocyaninates: Controlling the architecture of supramolecular aggregates

Cation-promoted supramolecular assembly of cobalt(II) and ruthenium(II) tetra-15-crown-5-phthalocyaninates is comparatively studied using the electronic absorption and infrared spectroscopy. The effects of the nature of the receptor and substrate on the architecture of the supramolecular aggregates formed are discovered. By contrast to Cu(II), Zn(II), and Ni(II) tetra-15-crown-5-phthalocyaninates, Co(II) and Ru(II) complexes are found to demonstrate sodium-potassium selectivity determined by the peculiarities of supramolecular structures formed upon the interaction with the cations.

Study of isotope effect upon lithium iodide complexation with benzo-15-crown-5 in water–chloroform extraction system

Extraction characteristics of chloroform–water system in lithium iodide extraction with benzo-15-crown-5 (B15C5) were studied. The complexation of the crown ether with LiI in organic phase was shown by IR spectroscopy. Isotope effect multiplication was performed by extraction chromatography technique. The magnitude of isotope separation factor (α) for 6Li-7Li pair was 1.017. The light lithium isotope is concentrated in organic phase.

Study of lithium complexes with benzo-15-crown-5 ether by X-ray diffraction and IR spectroscopy

The complex formation of lithium with benzo-15-crown-5 (B15C5) was investigated. The complexes LiB15C5H2OX, where X = Cl− (1), I− (2), (3), (5), and LiBF4B15C5 (4) were synthesized and studied by IR spectroscopy. Complexes 1–4 were examined by X-ray diffraction. According to IR spectroscopy data, the crown ether conformation changes upon dissolution. The interaction of the extracted complex with the solvent was identified.

Structures of the compounds preparatively isolated in the extraction of rare-earth metals with 2-diphenylphosphoryl-1-diphenylphosphorylmethoxy-4-ethylbenzene

The structures of 2-diphenylphosphoryl-1-diphenylphosphorylmethoxy-4-ethylbenzene (L), its adduct with water and nitric acid, and the complex [(L)2Nd(η2-O2NO)2](NO3) · NO3 · 2C6H6 were determined by X-ray diffraction. The above compounds were isolated under conditions very similar to those used for extractive separation of rare-earth metals in the system water-1,1,7-trihydrododecafluoroheptan-1-ol with L as an extractant. Assignment of the absorption bands in the IR spectra of the single crystals obtained was performed.

Extraction methods in development of Gd-loaded liquid organic scintillators for antineutrino detection: 2. Scintillators based on solutions of gadolinium 2-methylvalerate

Complexes of Gd with carboxylic acids C4–C9 were prepared, and their properties were studied: solubility in water and organic solvents in relation to temperature, melting points, and decomposition points. A procedure was developed for removing water from gadolinium 2-methylvalerate Gd(2MVA)3 to a final content not exceeding 0.01%. To increase the solubility of Gd(2MVA)3 in low-polarity organic solvents and to stabilize the resulting organic solutions, it was suggested to add extractants such as 2-methylvaleric acid (H2MVA) or neutral organophosphorus compounds: triisoamylphosphine oxide (TIAPO) or trioctylphosphine oxide (TOPO). Liquid Gd-loaded organic scintillators based on Gd(2MVA)3 solutions with additions of H2MVA, TIAPO, and TOPO in trimethylbenzene (TMB), phenylxylylethane (PXE), and their mixtures with dodecane were prepared. Long-term tests (up to 2 years) of the stability of the optical properties of the scintillators obtained proved their stability at temperatures of up to 30°C. At elevated temperatures (40°C and higher), the scintillators degrade. The previously made suggestion that water in the scintillator negatively affects its optical properties in prolonged storage was confirm

Synthesis and properties of calcium hydroxyapatite/carbon fiber composites

Composites comprising micrometer-sized carbon fibers (CFs) and biocompatible nanocrystalline calcium hydroxyapatite Ca10(PO4)6(OH)2 (HA, NCHA), containing 1.0, 2.0, and 5.0 wt % CFs, have been synthesized in the course of precipitation from aqueous solutions in the Ca(OH)2–H3PO4–CF–H2O system. Some physicochemical characteristics of the precursor CFs and synthesis products have been determined using chemical, X-ray diffraction, and thermal analyses, IR spectroscopy, and scanning and transmission electron microscopy. An analysis of composition–synthesis conditions–structure–particle size–property correlations indicates that the presence of CFs in HA/CF composites strongly decreases the sizes and modifies the habit of NCHA. A rise of CF content in the HA/CF composite is accompanied by a decrease in particle size and a rise in solubility of NCHA.

Environment of the Al3+ ion in Water–Acetone Solutions of Aluminum Chloride

Water–acetone solutions in the AlCl3–(CH3)2CO–H2O and AlCl3–(CH3)2CO–H2O–HCl systems were obtained and studied. In both cases, the solution separated into layers to form liquid fractions of lower and higher density. The IR spectra of the fractions were studied. In the light fraction, no AlCl3 was present, but hydrogen-bonded acetone–water complexes were detected. The spectra of the heavy fraction exhibited a broad band at ~3020–3040 cm–1 corresponding to the OH groups of water from aluminum hexahydrate. As the solvent is evaporated, the band narrows down, with its position being retained. The IR spectrum of the obtained solid becomes identical to the IR spectrum of the crystal hydrate AlCl3.(H2O)6. The structures and spectral and energetic parameters of Al(H2O)63+, Al(H2O)6+123+, Al((CH3)2CO)63+, Al((CH3)2CO)43+, and (CH3)2CO.H2O were calculated by the density functional theory method (B3LYP/6-31++G(d,p)). Relying on the results, an explanation was proposed for the experimentlly observed absence of acetone molecules in the Al3+ first coordination shell.

Structure of an Unordinary 1-D Cobalt(II) Polymer Formed upon the Dissolution of the Mononuclear Co(OOPh)2[O(H)Me]4 Adduct in Chloroform

The structure of the 1-D {[Co2(μ,η2-OOCPh)(μ-OOCPh)2(O(H)Me)2](μ-OOCPh)(HCCl3)}n polymer formed upon the dissolution of single crystals of the mononuclear Co(OOPh)2[O(H)Me]4 adduct containing coordinated labile methanol molecules in boiling chloroform was studied by X-ray diffraction.