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The single crystal X-ray diffraction study of the heterometallic cluster CpMnFePt(μ3-C=CHPh)(PPh3)(CO)6 is performed. The crystallographic characteristics are as follows: a = 32.356(15) A, b = 11.754(5) A, c = 20.114(9) A, β = 115.707(6)°, V = 6893(5) A3, space group C2/c, Z = 8, d calc = 1.741 g/cm3. The cluster molecule contains a bridging phenylvinylidene ligand coordinated to a metallic core in the form of a Mn–Fe–Pt chain (the Mn–Fe and Fe–Pt bond lengths are 2.6768(14) A and 2.6280(11) A respectively and the Mn⋯Pt distance is 3.6425(19) A).

The (1)H, (13)C and (15)N nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gas chromatography coupled to mass spectrometry (GC-MS) identification of a synthetic cannabinoid compound has been conducted. It was shown that this compound cannot be reliably distinguished from the closely related quinolin-8-yl indole-3-carboxylic acid derivative by an automatic search in MS library. Structural difference of the studied compound and known illicit compounds has been determined using 1D and 2D NMR spectroscopy. Analytical data for the identification of this compound were provided.

A method is developed for the determination of iron(III) and copper(II) in cognacs by capillary electrophoresis (CE) with diode array detection with limits of detection 0.06 and 0.6 mg/L, respectively. Foreign substances present in cognac do not interfere with the determination. The accuracy of the results of analysis was confirmed by the added-found method. The method was applied to the analysis of seven cognac samples. The data obtained by CE are in a good agreement with the results of inductively coupled plasma mass spectrometry.

1,3(I) and 1,5-dihydroxynaphthalens (II) as well as 1,5dimethylnaphthalene (III) are considered and investigated as template for building up various derivatives due to specific arrangement of the hydroxyl groups in its molecule (orthoandmetafor I; orthoand perifor II-III). Furthermore, some compounds containing resorcinol moiety exhibit depigmentation activity. A wide applications of adamantane derivatives allows to suggest that containing in its structure above-listed compounds I-III are of definite practical interest. Also it should be noted that aromatic compounds with an adamantane at the ortho-position to the hydroxyl groups are the key skeletons of synthetic retinoid analogues and supporting ligands of many homogeneous transition-metal catalysts. Moreover, recently much attention has been heeded to dearomatization reactions of aromatic and heteroaromatic compounds due to the highly reactive intermediates opportunities. Current report is an ongoing research of determination structure and features of adamantyl derivatives of dihydroxynaphthalenes by NMR spectroscopy. We describe here assignments of H and C NMR spectra of synthesized 1-adamantyl substituted compounds I-III. Additionally, previously defined patterns on the effect of OH-group in the orthoormetaposition to adamantane for its H and C NMR spectra have been confirmed on the basis of found spectral data. Such information can be useful for unambiguous interpretation of more sophisticated adamantyl derivatives of various naphthalene-units contain compounds, including their dearomatized derivatives.

The conditions of the sorption preconcentration of phenols from samples of natural and potable waters in Diapak P concentrator cartridges filled with super-cross-linked polystyrene are optimized. Countercurrent desorption with acetonitrile or methanol ensures the elimination the step of organic solvent evaporation. The observed reduction of the sorption of humic and fulvic acids (HFA) on the addition of sodium sulfite to the samples of natural and potable waters prior to their processing probably relates to the change of pH. The preconcentration of phenols from natural and potable waters at pH 6–8 substantially reduces the sorption of HFA. The method is used to determine phenols in samples of tap water and water from the Yenisei river by the added-found method.

The X-ray diffraction study of a new heterometallic cluster CpReFePt(μ3-C=CHPh)(CO)5[P(OPri)3]2 is performed. The crystallographic characteristics are as follows: a = 11.0275(4) A, b = 33.0367(12) A, c = 12.2691(5) A, β = 98.3660(10)°, V = 4422.2(3) A3, space group P21/n, Z = 4, dcalc = 1.744 g/cm3. The cluster contains the phenylvinylidene ligand coordinated with a trimetallic core in the form of a Re–Fe–Pt chain (the Re–Fe and Fe–Pt bond lengths are 2.794(7) A and 2.628(1) A respectively; the Re···Pt distance is 3.354(1) A).

Adamantylation of dihydroxynaphthalenes with the hydroxyl groups on the same or different rings leads to compounds that are convenient starting materials in target-oriented organic synthesis. Here, we report the (1)H and (13)C NMR assignments of eight 1-adamantyl substituted derivatives of 1,4-; 1,6- and 1,7-dihydroxynaphthalenes. The data acquired and peculiarities of their molecular structure are useful for extrapolation for prompt characterization of compounds containing adamantane, dihydroxynaphthalenes or naphthoquinone units.

A solvent-free reaction of phenol with 1-adamantanol in the presence of 1-bromoadamantane at ∼200 °C gives 2,4,6-tri(1-adamantyl)phenol. Pyrocatechol, o- and p-cresols, and p-halophenols under these conditions form diadamantylated derivatives.

We studied system peaks present in the electropherograms obtained in the separation of anions by capillary electrophoresis with indirect spectrophotometric detection and cathode electroosmotic flow (EOF) with a chromate background electrolyte. The system peaks correspond to the zones with changed concentration of the background electrolyte; they formed when the zones of each analyte passed through the outlet of the capillary and then moved towards the EOF detector. It has been revealed that the height and area of the system peaks linearly depends on the concentration of the corresponding anion and the areas of the system peaks can achieve 10% of the anion peak area. An algorithm has been proposed for the determination of the optimal conditions for anion separation using hydrodynamic pressure for the regulation of the EOF flow rate. This algorithm prevents the overlapping of the anion and system peaks.

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала. We developed a procedure for determining manganese(II) in wines by stripping voltammetry on a graphite electrode as a poorly soluble compound. The detection limit of manganese(II) is 50 µg/L. The dependence of the analytical signal of manganese(II) on its concentration in solution is linear in the range 0.1–3 mg/L. It is demonstrated that the results of the stripping voltammetric determination of manganese(II) in wines agree with the data obtained by inductively coupled plasma mass spectrometry and EPR spectrom etry.

Theoretical Hartree-Fock, MP2 and density functional (SVWN, BLYP, B3LYP) computations have been first made to calculate the equilibrium geometry and vibration frequencies of CO rhodium(I) chelate dicarbonyl complexes with monocharged bidentate ligands like β-diketonate R1COCHCOR2, iminoketonate R1COCHC(NH)R2, and β-diiminate R1C(NH)CHC(NH)R2 with substituents at carbon atoms R1, R2 = H, CH3, CF3. Consideration of electron correlation was shown to be especially important for the reasonable representation of bond distances with metal atom and CO vibration frequencies. The MP2 computation of exchange-correlation effects, as compared to density functional technique, results in a better description of frequency difference of symmetrical and asymmetrical modes of CO vibrations: inaccuracy in Δν(CO) description recedes from 12–16 cm−1 to 4 cm−1. The dependence between electron density distribution in complexes and spectral characteristics of terminal carbonyl groups was traced. Alteration of CO vibration frequencies was interpreted in terms of electron density shift from occupied d-orbitals of the metal to π*-orbitals of carbonyl groups. Population of CO π *-orbitals increases and CO vibration frequencies decrease on lessening of the electronegativity of donor atoms of a chelate ligand when passing on from oxygen to nitrogen and further among the substituents R CF3>H>CH3.

The adamantylation of phenols with 1-adamantanol in the presence of 1-bromoadamantan is described.

Adamantylation of dihydroxynaphthalenes with the hydroxyl groups on the same or different rings leads to compounds that are convenient starting materials in target-oriented organic synthesis. Here, we report the (1)H and (13)C NMR assignments of eight 1-adamantyl substituted derivatives of 1,4-; 1,6- and 1,7-dihydroxynaphthalenes. The data acquired and peculiarities of their molecular structure are useful for extrapolation for prompt characterization of compounds containing adamantane, dihydroxynaphthalenes or naphthoquinone units.

The system peaks that often appear on electropherograms in anion separation by CE with indirect spectrophotometric detection, negative voltage polarity and cathodic EOF are studied. The system peaks are shown to correspond to the zones with the changed concentration of the BGE constituents; they appear while the zone of each analyte anion passes through the outlet end of the capillary and are transported to the detector by EOF. An equation is suggested for predicting migration times of the system peaks with an error of 1%. The ratios of the system peak area to the analyte peak area are found to amount to 20%. It is shown that it is possible to avoid overlapping of the system peaks and analyte peaks by controlling the EOF velocity owing to hydrodynamic pressure. Using the mathematical simulation of CE shows that the system peaks and baseline shift can result from changing the transference numbers of the BGE ions and analyte ions at the capillary edge. The cases when the system peak may be incorrectly identified as the peak of analyte ion are considered. In order to avoid such errors, some practical recommendations are given.