Ilya V. Korolkov

Binuclear Bi(III) halide complexes with 4,4′-ethylenepyridinium cations: luminescence tuning by reversible solvation

Two new complexes based on 4,4′-ethylenepyridinium cations and binuclear Bi(III) anionic complexes, (H2bpe)2[Bi2X10]·2H2O (bpe = 1,2-bis(4-pyridyl)ethane; X = Cl (1), Br (2)), have been synthesized and characterized by X-ray diffractometry. In both cases, loss of solvent H2O molecules affects the luminescence behavior, resulting in increase of intensity (ca. 5-fold). Desolvation is reversible, which is of potential use in chemosensor systems.

Terbium oxide films grown by chemical vapor deposition from terbium(III) dipivaloylmethanate

Terbium oxide films have been grown on Si(111) substrates by decomposition of Tb(dpm)3 vapor in argon flow at Tb(dpm)3 source temperatures of 170 and 190°C and substrate temperatures from 470 to 550°C. The films have been annealed in air at temperatures of 400, 650, and 800°C. X-ray diffraction characterization results show that the films grown by chemical vapor deposition consist of cubic Tb2O3. The films annealed in air at 650 and 800°C are isostructural with Tb4O7, and those annealed at 400°C are isostructural with Tb11O20. According to X-ray photoelectron spectroscopy data, the 9-nm-thick surface layer of the Tb2O3 film has the correct stoichiometry O: Tb = 1.48, whereas the film annealed at 800°C has O: Tb = 1.85. Raman spectroscopy data demonstrate that the concentration of carbon-containing species on the surface of the films decreases with decreasing substrate temperature and can be brought to zero by air annealing at 800°C.

Syntheses of [Rh(NH3)5Cl][MCl6] (M = Re, Os, Ir) and Investigation of Their Thermolysis Products. Crystal Structure of [Rh(NH3)5Cl][OsCl6]

Binary complex salts [Rh(NH3)5Cl][MCl6], where M = Re, Os, Ir, have been synthesized and characterized. X-ray diffraction analysis indicated that the salts are isostructural. According to X-ray phase analysis, the products of their thermolysis in hydrogen are monophase stoichiometric nonequilibrium solid solutions Rh0.5M0.5 (M = Re, Os, Ir). The molecular and crystal structures of [Rh(NH3)5Cl][OsCl6] were determined in an X-ray structural analysis.

Volatile Pd–Pb and Cu–Pb heterometallic complexes: structure, properties, and trans -to- cis isomerization under cocrystallization of Pd and Cu β-diketonates with Pb hexafluoroacetylacetonate

Preparation of volatile heterometallic precursors is a significant step on the way to advanced multicomponent materials. Study of molecular transformations in solution upon precursor synthesis is of importance to optimize the preparation of the stable solid product of desired composition. Two new volatile heterobimetallic complexes, cis-PdL2*Pb(hfa)2 and cis-CuL2*Pb(hfa)2, were obtained (L = 2-methoxy-2,6,6-trimethylheptane-3,5-dionate, hfa = 1,1,1,5,5,5-hexafluoropentane-2,4-dionate) under cocrystallization of trans-bis-beta-diketonates of Pd(II) and Cu(II) with Pb(hfa)2 from organic solvents. Crystals of these compounds are built of discrete bimetallic molecules where transition metal complex isomerized from trans-to-cis form. Complexation followed by isomerization was studied by solution NMR. The bimetallic molecular species were formed early in solution. Enthalpy and activation energy of isomerization were estimated to be 49 and 93 kJ mol−1, respectively. A new synthesis technique of Pd(II) beta-diketonates which is distinguished by simplicity and selectivity as well as the crystal structure of trans-PdL2 is described. Volatility of all obtained compounds was confirmed by thermogravimetric analysis and fractional sublimation in vacuum; Pd-containing heterobimetallic complex appeared to be more volatile than both the initial monometallic complexes and Cu-containing complex.

Polyoxomolybdate-supported bismuth trihalides [Mo8O26(BiX3)2](4-) (X = Cl, Br, I): syntheses and study of polymorphism.

Octamolybdate complexes TBA4[Mo8O26(BiX3)2] (TBA = n-tetrabutylammonium, X = Cl (1), Br (2), I (3)) were obtained by straightforward syntheses from TBA4[Mo8O26] and corresponding Bi(III) halides in MeCN. All compounds were structurally characterized; in all cases, {BiX3} fragments are coordinated by two oxygen atoms of polyoxometalate core. Occurring polymorphism is also discussed.

Complexes of non-lacunary Keggin- and Dawson-type polyoxometalates with Pb(II): formation of 1D coordination polymers with different bonding modes

A new coordination polymer based on Keggin-type [SiW12O40]4− and Pb2+ ions, {Pb2(μ2-DMF)2(DMF)8(SiW12O40)} (1a), was prepared by a reaction between H4[SiW12O40] and Pb(NO3)2 in N,N-dimethylformamide (DMF). Varying the crystallization conditions, a complex with a slightly different coordination mode of the {Pb2} unit and solvate composition, {Pb2(μ2-DMF)2(DMF)8(SiW12O40)}·DMF (1b), can be obtained. The complex containing Well–Dawson polyoxoanions, {(Pb(μ2-DMF)3(DMF)6)(Pb(DMF)5)(P2W18O62)}·0.5DMF·1.3H2O (2), was prepared by a similar strategy.

High-throughput powder X-ray diffraction, IR-spectroscopy and ion chromatography analysis of urinary stones: A comparative study

AbstractThe instrumental qualitative analysis of urinary stones is a critical step in clinical practice and urological research. A powder X-ray diffraction, IR-spectroscopy and ion chromatography have been applied for the qualitative analysis of 20 urinary stones. Suggestions for a sample preparation and an optimal measurement strategy were formulated. The main difficulties for the powder X-ray diffraction qualitative analysis are a limiting amount of the sample and a preferential orientation of crystals, both issues should be minimized by the special sample preparation. Urinary stones samples have been clustered into four groups using different sets of numerical input data (cation and anion content, phase composition). At the same time a high-throughput multivariate clustering has been applied for powder X-ray diffraction and IR-spectroscopy data. The multivariate whole-profile approach can be used as a tool for a high-throughput time reducing technique for clinical practice, when a quick and stable classification of samples is required. All three sets of the data can be automatically separated into three clusters: oxalate-reach, oxalate-pure and non-oxalate samples. Uricite-pure and uricite-rich samples can be easily clustered.n

Multifunctional Metal–Organic Frameworks Based on Redox-Active Rhenium Octahedral Clusters

The redox-active rhenium octahedral cluster unit [Re6Se8(CN)6]4- was combined with Gd3+ ions and dicarboxylate linkers in novel types of metal-organic frameworks (MOFs) that display a set of functional properties. The hydrolytically stable complexes [{Gd(H2O)3}2(L)Re6Se8(CN)6]·nH2O (1, L = furan-2,5-dicarboxylate, fdc; 2, L = thiophene-2,5-dicarboxylate, tdc) exhibit a 3D framework of trigonal symmetry where 1D chains of [{Gd(H2O)3}2(L)]4+ are connected by [Re6Se8(CN)6]4- clusters. Frameworks contain spacious channels filled with H2O. Solvent molecules can be easily removed under vacuum to produce permanently porous solids with high volumetric CO2 uptake and remarkable CO2/N2 selectivity at room temperature. The frameworks demonstrate an ability for reversible redox transformations of the cluster fragment. The orange powders of compounds 1 and 2 react with Br2, yielding dark-green powders of [{Gd(H2O)3}2(L)Re6Se8(CN)6]Br·nH2O (3, L = fdc; 4, L = tdc). Compounds 3 and 4 are isostructural with 1 and 2 and also have permanently porous frameworks but display different optical, magnetic, and sorption properties. In particular, oxidation of the cluster fragment switches off its luminescence in the red region, and the incorporation of Br- leads to a decrease of the solvent-accessible volume in the channels of 3 and 4. Finally, the green powders of 3 and 4 can be reduced back to the orange powders of 1 and 2 by reaction with hydrazine, thus displaying a rare ability for fully reversible chemical redox transitions. Compounds 1-4 are mentioned as a new class of redox-active cluster-based MOFs with potential usage as multifunctional materials for gas separation and chemical contamination sensors.

Synthesis and crystal structure of nitrosoruthenium complexes cis-[Ru(NO)Py2Cl2(OH)] and cis-[Ru(NO)Py2Cl2(H2O)]Cl. Photoinduced transformations of cis-[Ru(NO)Py2Cl2(OH)]

The interaction of K2[Ru(NO)Cl5] with an excess of pyridine followed by concentration of the reaction solution afforded two crystalline modifications of cis-[Ru(NO)Py2Cl2(OH)] (1a and 1b). The treatment of this hydroxocomplex with hydrochloric acid gave an aquacomplex cis-[Ru(NO)Py2Cl2(H2O)]Cl (2). The prepared complexes were characterized by elemental analysis, X-ray diffraction, infrared and 1H NMR spectroscopies. Infrared and Raman spectroscopies provided evidence that irradiation of cis-[Ru(NO)Py2Cl2(OH)] (λ ∼ 450 nm, T = 80 K) resulted in photoisomerization with the formation of metastable states MS1 (isonitrosyl complex) and MS2 (η2-coordination of the NO). The population of the MS1 state amounts to 60%. Differential scanning calorimetry (DSC) was used to determine the activation parameters for MS1: Ea = 65.2(3) kJ mol−1, k0 = 1.05(7) × 1014 s−1. These experimental data agree well with DFT calculations.

Synthesis, Structure, and Thermal Decomposition of Chloropentamminerhodium(III) Hexabromoplatinate(IV)

The binary complex salt [Rh(NH3)5Cl][PtBr6] was synthesized and studied by X‐ray structural analysis. The crystallographic data are as follows: a = 12.013(2) Å, b = 8.401(2) Å, c = 15.999(3) Å, β = 91.13(3)°, V = 1614.3(6) Å3, space group P21/m, Z = 4, dx = 3.70 g/cm3, R = 0.086. The thermal decomposition of the salt in a hydrogen atmosphere is shown to produce a Rh0.5Pt0.5 solid solution with an FCC cell [a = 3.864(2) Å. The thermal decomposition of the salt in a helium atmosphere proceeds via the formation of metallic Pt and RhBr3 and finally results in a mixture of several solid solutions.