The monodentate phosphoryl-containing ligand 1-Ac-2-[Ph2P(O)]-cyclohexane (L) bearing two asymmetric carbon atoms is synthesized. The study of its crystal structure shows that L is a racemic mixture of (1R,2S) and (1S,2R) stereoisomers. The complex formation of L with TiF4 in СН2Сl2 is studied by 19F1Н and 31Р1Н NMR spectroscopy. The compositions of the complexes formed in the solution are determined. Racemic and meso-diastereomers of the octahedral complex cis-TiF4L2 are formed in the solution as found by an analysis of the 19F and 31Р NMR spectra taking into account the concept of heterotropy of organic compounds. The influence of the optical configuration of stereoisomers of the monodentate ligand coexisting in the coordination sphere of the [MF4L2] octahedral tetrafluoro complexes of transition d0 metals on the chemical shifts of the fluorine atoms arranged in the trans positions relative to each other is shown. In the meso-diastereomer of cis-TiF4L2, this results in a nonequivalence of the fluorine atoms on the F–Ti–F' ordinate of the octahedron, and the spin-spin coupling constant JFF' = 286.1 Hz is observed in the 19F1H NMR spectrum.

The process of rearrangement of the octadecahydroeicosaborate anion [trans-B20H18]2– → [iso-B20H18]2– in organic solvents (acetonitrile, DMF, DMSO) under UV irradiation has been studied using 11B NMR spectroscopy in dynamics. It has been shown that the time of complete isomeric transition depends on the solvent used. In acetonitrile, complete conversion of the [trans-B20H18]2– anion to the iso form is achieved in 1 h; in DMF, the process takes about 2 h; in DMSO, it takes about 3 h. The reverse process of rearrangement of the macropolyhedral borohydride anion [iso-B20H18]2– → [trans-B20H18]2– has been studied under the influence of temperature in DMF; it has been shown that an increase in the reaction time and temperature of the reaction solution is accompanied by degradation of the boron cluster.

Thermodynamic characteristics and water evaporation mechanism from silica structure in temperature range 100–1000°С have been studied by thermogravimetry, mass spectrometry, 1Н and 29Si NMR. It has been shown that liquid, surface-bound, and molecular-dispersed water is present on the surface and in the bulk of silica particles. The role of different (ОН)n groups in the structural change of silica upon thermal and thermal steam treatment has been shown. A method for preparation of anhydrous silica used in the manufacture of high-quality quartz glass has been proposed.

Aim. The comparison of saliva 1Н NMR spectra in patients with wedge-shaped lesions before and after treatment.Materials and methods. Saliva as a study material was taken from patients with wedge-shaped lesions before and after treatment. The treatment method was remineralizing therapy that included the use of the oral rinse containing zinchydroxyapatite. 1Н NMR spectroscopy was chosen as an investigation method.Results. In most cases it is noted that after treatment the content of propionic and butyric acids was on the rise in relation of acetic acid. Overall concentration of 1Н protons didn't change significantly.Conclusions. 1Н NMR spectra analysis shows organic acid distribution in oral liquid before and after treatment, which helps to evaluate its response.

The catalytic activity of bis(isopropoxo)titanium(4+) complexes containing 1,2-diolate ligands activated with aluminum alkyl chlorides and dibutyl magnesium in the copolymerization of ethylene and hexene-1 has been studied. The effect of the precatalyst structure and the organoaluminum activator composition on the catalytic activity, the incorporation of hexene-1, and the copolymer microstructure has been studied. The synthesized copolymers have been characterized by DSC, GPC, and 13 C NMR. The complexes containing perfluorophenyl substituents exhibit the highest activity in this set and provide the highest degree of incorporation of the comonomer. The replacement of Et 2 AlCl with Et 3 Al 2 Cl 2 leads to a significant decrease in both productivity and the degree of incorporation of hexene-1 into the copolymer. The mechanical properties of the resulting copolymers have been studied.

The complex formation of TiF 4 with the phosphorylated ketone Ph 2 P(O)CH(Me)CH 2 C(O)Et (L), containing an asymmetric carbon atom in the aliphatic hydrocarbon group and representing a racemic mixture of enantiomers, was studied by 19 F{ 1 H} and 31 P{ 1 H} NMR spectroscopy. The composition of complexes formed in the solution was determined; analysis of the 19 F NMR spectra resorting to the heterotropicity concept was used to assign the resonance lines to two chiral optically active racemic and meso- stereoisomers of cis -TiF 4 L 2 . The configurations of enantiomers of the monodentate ligand coexisting in the coordination sphere were found to have a crucial effect on the axial fluorine atoms of mixed octahedral cis -tetrafluoro d 0 transition metal complexes. A new efficient method was developed for the synthesis of ligand L.

The first complexes of cerium tetrafluoride in solutions were investigated by 19F NMR and IR spectroscopy. The temperature dependence of the 19F NMR spectra was, studied and it was concluded that mobile equilibrium exists between the molecular adduct and singly charged ionic forms, including geometric isomers. The static probability of stereoisomer formation [CeF4(dmso)4] was calculated using the square antiprism configuration and, based on the relative intensity of the 19F NMR resonance signals, they were assigned to possible stereoisomers. Quantum-chemical calculations of the structure of the isomer [CeF4(dmso)4], the isomer [CeF3(dmso)5]+ and [CeF5(dmso)3]-, showing their thermodynamic stability, were performed.

The first complexes of cerium tetrafluoride in solutions have been studied by 19 F NMR and IR spectroscopy. The temperature dependence of the 19 F NMR spectra has been explored, and conclusion has been made that dynamic equilibrium between the molecular adduct and singly charged ionic forms, including geometric isomers, exists in solution. The statistical probability for the formation of [CeF 4 (dmso) 4 ] stereoisomers of square antiprism configuration has been calculated, and their assignment to possible stereoisomers have been made on the basis of relative intensities of the 19 F NMR signals. Quantum-chemical calculations of the structure of one of the possible isomers have been performed for the [CeF 4 (dmso) 4 ] molecular adduct, [CeF 3 (dmso) 5 ] + cation, and [CeF 5 (dmso) 3 ] – anion to show their thermodynamic stability.

The process of obtaining silicon dioxide upon the interaction of fluorosilicic acid with an aqueous solution of ammonia is studied. The fluorine-containing compounds in synthesized dioxide are identified by 19 F NMR spectroscopy. It is shown that the two-stage method of precipitation followed by washing, allows producing silicon dioxide with a fluorine content of units of ppm.

NMR-spectroscopy has a growing importance in medicine as a tool for metabolic screening for abnormalities in biological fluids. Carbon is the basis of the most biologically significant molecules and 13 C NMR spectroscopy involves the direct measurement of these compounds. Clinical examination of patients, men and women, aged from 18 to 30 years, was carried out. Particular attention was paid to the detection of wedge-shaped defects of teeth hard tissues at various stages of this disease, as well as co-factors of its occurrence. NMR spectroscopy of carbon isotope 13 С nuclei of oral liquid samples from a healthy person (control) and patients with severe wedge-shaped lesions was chosen as a laboratory testing method. Studies have shown the analytical capabilities of oral liquid 13 C NMR spectroscopy of high resolution and promising directions for finding markers of dental diseases in their early stages.

The composition and structure of the products of the reaction of titanium tetrafluoride with Ph2P(O)(CH2)2C(O)NМе2 (L), the simplest representative of diphenyl[2-(N,N-dialkylcarbamoyl)ethyl]phosphine oxides, in a СН2Сl2 have been studied by 19F and 31P NMR. It has been shown for the first time that functionalized phosphine oxides form stable seven-membered chelate heterocycles on complexes of d° transition metals. On the basis of NMR data, previously unknown conformational isomerism of the seven-membered TiOPCCCO heterocycle in solution has been proposed. A simple and rather efficient method of synthesis of the ligand (L) from commercially available reagents has been developed.

The trans–iso isomerization of the dimeric borohydride cluster anion [B 20 H 18 ] 2– in the course of the silver(I) complexation reaction with triphenylphosphine has been described for the first time. The isomeric complexes [Ag 2 (Ph 3 P) 6 [ trans -B 20 H 18 ]] and [Ag 2 (Ph 3 P) 6 [ iso -B 20 H 18 ]] have been isolated and characterized by physicochemical methods. The structures of the compounds have been determined by X-ray crystallography.

In dentistry, the implementation of the principles metabolomics is just beginning, and obviously has a great future. One of the goals of metabolomics is the early diagnosis of disease at a stage when they may not have clinical manifestations. clinical examination of patients was carried out, men and women, aged from 18 to 30 years. Particular attention was paid to the detection of wedge-shaped defects of teeth hard tissues at various stages of this disease, as well as co-factors of its occurrence. Laboratory test method was selected nuclei magnetic resonance spectroscopy of proton and carbon nuclear isotope sample liquid oral healthy person (control) and patients with severe defects tapered teeth. The data show that the spectroscopy makes it possible to determine the concentration and composition of the low molecular weight organic substances in samples of saliva, which will serve as a subject for further research.

für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namensnennung 4.0 Lizenz. 79,81 Br and 133Cs Nuclei Quadrupole Interactions and Phase Transitions in Crystalline Caesium Perbromate