M. Yu. Skripkin

St Petersburg University | SPBU · Department of General and Inorganic Chemistry

The structural features and luminescent properties of heterometallic Tb–Gd, Tb–La, and Tb–Y terephthalate metal–organic frameworks, namely (TbxM1−x)2(1,4-bdc)3∙4H2O (M = Gd, La, Y), were studied in detail in a wide concentration range (x = 0.001–1). The crystalline phase of synthesized compounds corresponds to Ln2(1,4-bdc)3·4H2O. The lifetime of 5D...

New heterometallic antenna terephthalate MOFs, namely, (EuxM1−x)2bdc3·4H2O (M = Y, La, Gd) (x = 0.001–1), were synthesized by a one-step method from aqueous solutions. The resulting compounds are isomorphic to each other; the crystalline phase corresponds to Ln2bdc3∙4H2O. Upon 300 nm excitation to the singlet excited state of terephthalate ions, al...

The stability constants of triply charged lanthanide ions complexes with citric acid of 1:2 stoichiometry weremeasured by potentiometric titration in a wide pH range, and the relationship between the constants and the lanthanide type was analyzed. A mathematical model for the equilibrium in studied solutions was proposed.

Методом гидротермального синтеза впервые синтезированы нанокристаллические люминофоры состава NaGd 1- x Nd x F 4 ( x = 0-1). Полученные соединения кристаллизуются в гексагональной сингонии, структурный тип - β-NaYF 4 . Ионы неодима(III) изоморфно замещают ионы гадолиния. Максимальная интенсивность люминесценции в ближней ИК области при возбуждении...

Microcrystalline upconversion materials NaY0.8- x Yb0.2Ho x F4 ( x = 0-0.1) were synthesized by hydrothermal synthesis for the first time. All the synthesized compounds have hexagonal β-NaYF4 crystalline phase. Holmium(III) ions isomorphically replace yttrium ions. The maximum upconversion emission intensity is observed for NaY0.78Yb0.2Ho0.02F4 in...

A method is presented for isolating iodine isotopes from aqueous coolant of the nuclear power plants’ first circuit. At first, all forms of iodine radionuclides are converted into molecular form by the sequential addition of a carrier–potassium iodide, as well as hydroxylamine chloride, nitric acid and potassium nitrite. Then molecular iodine is tr...

The series of luminescent NaYF4:Sm3+ nano- and microcrystalline materials co-doped by La3+, Gd3+, and Lu3+ ions were synthesized by hydrothermal method using rare earth chlorides as the precursors and citric acid as a stabilizing agent. The phase composition of synthesized compounds was studied by PXRD. All synthesized materials except ones with hi...

Luminescent, heterometallic terbium(III)–lutetium(III) terephthalate metal-organic frameworks (MOFs) were synthesized via direct reaction between aqueous solutions of disodium terephthalate and nitrates of corresponding lanthanides by using two methods: synthesis from diluted and concentrated solutions. For (TbxLu1−x)2bdc3·nH2O MOFs (bdc = 1,4-benz...

Controlling oxygen content in the primary circuit of nuclear reactors is one of the key tasks needed to ensure the safe operation of nuclear power plants where lead-bismuth eutectic alloy (LBE) is used as a coolant. If the oxygen concentration is low, active corrosion of structural materials takes place; upon increase in oxygen content, slag accumu...

A new series of luminescent heterometallic europium(III)–lutetium(III) terephthalate metal–organic frameworks, namely (EuxLu1−x)2bdc3·nH2O, was synthesized using a direct reaction in a water solution. At the Eu3+ concentration of 1–40 at %, the MOFs were formed as a binary mixture of the (EuxLu1−x)2bdc3 and (EuxLu1−x)2bdc3·4H2O crystalline phases,...

Two series of β-NaYF4:Ln3+ nanoparticles (Ln = La–Nd, Sm–Lu) containing 20 at. % and 40 at. % of Ln3+ with well-defined morphology and size were synthesized via a facile citric-acid-assisted hydrothermal method using rare-earth chlorides as the precursors. The materials were composed from the particles that have a shape of uniform hexagonal prisms...

This paper discusses the processes of the long-lived 137Cs and 60Co immobilization on titanium surfaces in simulated light water reactor primary circuit environments. This study is prompted by numerous problems in both the maintenance of equipment during reactor operation and the dismantling of the reactor after the completion of the operation, whi...

Relying on a recently suggested protocol that furnishes convenient access to variously substituted 2-pyridyl ureas, twelve hitherto unknown Cu(II) complexes have been synthesized in the present work and their structures were evaluated by elemental analysis, HRMS, IR spectroscopy, and X-ray diffraction study. Two structural motifs ([Cu(L)2Cl]+[Cl]−...

Comprehensive study of the structure and bonding of disodium, dipotassium and diammonium di-o-phthalatocuprates(II) dihydrates has been undertaken. The crystal structure of ammonium o-phthalatocuprate has been determined. The identity of structures of phthalatocuprate chains in potassium and ammonium salts has been revealed. Vibrational spectra of...

The luminescent coarse-, micro- and nanocrystalline europium(III) terephthalate tetrahydrate (Eu2bdc3‧4H2O) metal-organic frameworks were synthesized by the ultrasound-assisted wet-chemical method. Electron micrographs show that the europium(III) terephthalate microparticles are 7 μm long leaf-like plates. According to the dynamic light scattering...

Thermodynamic data on the properties of the water-based electrolyte systems are very valuable for fundamental physical chemistry and for industrial applications. The missing data both on the dilution and dissolution enthalpies for the ternary CsCl−MgCl2−H2O mixed electrolyte system were investigated by means of the calorimetry method. The dilution...

β-NaYF4:Eu³⁺microparticles co-doped with Gd³⁺ions were obtained by hydrothermal synthesis at 180 °C using citric acid as a stabilizing agent. All synthesized materials have a β-NaYF4crystalline phase, where the unit cell volume increases upon the addition of Eu³⁺and Gd³⁺ions. The particles have a hexagonal prism shape and a size of 40-714 nm, where...

β-NaYF4 microcrystals co-doped with Yb3+, Er3+/Tm3+, and Gd 3+ ions were synthesized via a hydrothermal method using rare-earth chlorides as the precursors. The SEM and XRD data show that the doped β-NaYF4 form uniform hexagonal prisms with an approximate size of 600-800 nm. The partial substitution of Y by Gd results in size reduction of microcrys...

The ultrafast photochemistry of the [Cr(NCS)6]³⁻ complex upon excitation to the ⁴T2 ligand-field (LF) state was studied in dimethylsulfoxide (DMSO) and N,N-dimethylformamide (DMF) in a wide temporal range (100 fs – 9 ms) by a combination of femtosecond and nanosecond transient absorption spectroscopy techniques and supported by quantum-chemical DFT...

The results of the study of ternary systems containing copper, cobalt, nickel, and cadmium halides and sulfates in binary water-organic and mixed organic solvents are summarized. The influence of the donor-acceptor properties of the ternary system components, the relative dielectric permittivity, and the intermolecular association in the mixed solv...

The influence of ionic interactions in ternary aqueous and aqueous-organic solutions of metal halides on the structure of the solid phases in equilibrium with the solutions is analyzed. An original classification of double and complex salts, reflecting the peculiarities of their structure, is given. The conditions for the formation of various types...

Four complexes [Ni(DMA)2(H2O)4]Cl2·2H2O, [Ni(DMF)2(H2O)4]Cl2·2H2O, and [Ni(DMA)6][NiCl4], [Ni(DMF)2(H2O)2Cl2] were isolated from ternary water-organic saline systems containing nickel chloride and N, N-dimethylacetamide-water and N, N-dimethylformamide-water binary solvents. The obtained complexes were studied by X-ray structural analysis. The form...

Ultrafast excited-state dynamics of CuCl4²⁻ in acetonitrile is studied by femtosecond broadband transient absorption spectroscopy following excitation of the complex into all ligand field (LF, or d-d) states, and into the two ligand-to-metal charge transfer (LMCT) states corresponding to the most intense steady-state absorption bands. The LF excite...

Solubility of copper(II) chloride at 25°C in binary organic solvents consisting of dimethyl sulfoxide, N,N-dimethylacetamide, and 1,4-dioxane was determined by the isothermal saturation method. The shape of solubility isotherms for all ternary systems under study is connected with the structural type of formed copper chloride solvates, the composit...

The results of spectrophotometric study and quantum chemical calculations for copper(II) chloro- and bromocomplexes in acetonitrile are reported. Electronic spectra of the individual copper(II) halide complexes were obtained in a wide spectral range 200–2200 nm. Stability constants of the individual copper(II) halide complexes in acetonitrile were...

Five solvates, [CdBr2(DMF)]n , [CdBr2(DMA)]n , [CdI²(DMF)]n , [Cd(DMF)6][Cd2I6], and {[Cd(DMA)6][Cd5I12]n }m , were isolated from the ternary systems CdX2–L–H2O (X = Br, I; L = N,N-dimethylacetamide, N,N-dimethylformamide) and characterized by the X-ray single crystal analysis. The structures of the first three solvates is similar to each other in...

It was proved by the IR spectroscopy that the first coordination sphere of nickel cations in the NiCl2·2DMSO·9H2O, NiCl2·5DMSO·4H2O, and NiCl2·4DMSO·2H2O compounds contains dimethyl sulfoxide and water ligands. According to X-ray structural analysis, in crystals of the NiCl2·4DMSO·2H2O compound, noncovalent contacts between sulfur atoms of neighbor...

Solvation of europium ions in mixed aqueous-organic solvents was studied in the solutions of europium (III) triflate and chloride. Europium ions are preferentially solvated only in water-dimethylsulfoxide systems. In aqueous dimethylformamide and dimethylacetamide preferential hydration in water-deficient region was observed. The total solvation nu...

Non-radiative relaxation dynamics of CuCl4(2-) complexes photoexcited into the highest-energy ligand-field electronic state ((2)A1) is studied in acetonitrile, dichloromethane, and chloroform solvents, as well as in acetonitrile-water and in acetonitrile - deutered water mixtures. Due to ultrafast internal conversion, this excited state directly co...

The synthesis of conductive gold and copper-gold microstructures with high developed surface based on the method of laser-induced metal deposition from solution was developed. The topology and crystallization phase of these structures were observed by means of scanning electron microscopy and X-ray diffraction, respectively. The electrochemical pro...

Solubility of cadmium chloride at 25°C in four ternary systems containing mixed water-organic solvents was measured by the isothermal saturation method. Dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, and 1,4-dioxane were used as organic components. In all systems the organic component addition provides a salting-out effect within...

Solubility in the systems CdX2–H2O–Solv (X = Br, I; Solv = dimethyl sulfoxide, N,N-dimethyl acetamide, N,N-dimethyl formamide, and 1,4-dioxane) at 25°C was measured by the isothermal saturation method. A relation between the shape of the solubility isotherm and the structure of the binary solvent depending on its composition was found. Positions of...

Solubility of salts in the systems MCl2–H2O–Solv (M = Co, Ni) and CoBr2–H2O–Solv (Solv = dimethyl sulfoxide, dimethyl formamide, and dimethyl acetamide) at 25°C was measured experimentally. Dominating species of cobalt and nickel halides existing in various concentration regions were identified by analysis of electron absorption spectra. It was sho...

Photochemistry of copper(II) monochlorocomplexes in methanol and acetonitrile solutions is studied by UV-pump/broadband deep-UV-to-near-IR probe femtosecond transient absorption spectroscopy. Upon 255- and 266-nm excitation, the complexes in acetonitrile and methanol, respectively, are promoted to the excited Ligand-to-Metal Charge Transfer (LMCT)...

Solubility at 25°C has been determined in the MSO4–H2O–Solv systems (M = Co, Cu, or Cd; Solv = dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, tetrahydrofuran, or dioxane) via the isothermal saturation method. Analysis of the solubility as function of the permittivity and donor power of solvents along with the information on the cations...

Copper(II) complexes are extremely labile with typical ligand exchange rate constants of the order of 10(6)-10(9) M(-1) s(-1). As the result, it is often difficult to identify the actual formation mechanism of these complexes. In this work, using UV-vis transient absorption when probing in a broad time range (20 ps - 8 µs) in conjunction with DFT/T...

Photochemistry of [Cu(MeCN)(3)Cl](+), [Cu(MeCN)Cl-3](-), and [CuCl4](2-) copper(II) chlorocomplexes in acetonitrile solution is studied by means of the combination of the steady-state photolysis and ultrafast transient absorption methods. The main relaxation pathways of the initially excited ligand-to-metal charge transfer states are internal conve...

Study of molar conductivity of several palladium(II) complexes has revealed that cationic acyclic diaminocarbene complexes of palladium(II) containing carbohydrazide fragment in the carbene ligand are capable of reversible cyclization to form a six-membered C,O-chelate. This process is favored by factors enhancing dissociation of the anionic ligand...

Complexation between hexavalent neptunium and nitrate was studied in aqueous nitric acid solution using optical absorption, vibrational and X-ray absorption spectroscopies. Distributions of aqueous [NpO2](2+), [NpO2(NO3)](+) and [NpO2(NO3)2] species were obtained as a function of nitric acid concentration between 0 and 14 M. The crystal structure o...

Crystal structure and vibrational spectra of a new zinc metal–organic network, {[Zn3(tp)4]·4H2O}n, 1, have been studied. The compound was constructed from Zn(NO3)2·6H2O and H2tp ligand (H2tp = 1,4-benzenedicarboxylic acid) by solvothermal synthesis in DMF. Its framework is built from the trinuclear SBUs as eight-connected nodes and tp ligands as sp...

The crystal structure and vibrational spectra of a new Zn(II) terephthalate 2D metal–organic framework, [Zn3(tp)3(DMSO)2)]n (H2tp = terephthalic acid; DMSO = dimethyl sulfoxide), together with its thermal behavior and photoluminescence properties have been studied. The structure shows a rare layered structure with 6-connected hxl topology, construc...

In the study of the solution-solid phase equilibrium in CuX2-S-H2O system (X = Cl, Br, S = dimethyl sulfoxide, N, N-dimethylformamide, tetrahydrofuran, 1,4-dioxane) at 25A degrees C we established the effect of the solvent properties and the type of the halide ligand (dielectric premeability, donor number, hydrophobicity) on the solubility of the s...

Equilibrium adsorption of copper(II) ions on red mud (alumina industrial wastes) modified by various methods was studied. The effect exerted by the nature the modifier (NaHSO4, NaCl + HCl, and H2SO4) on the sorption activity of red mud was determined.

Crystal structures and vibrational spectra of three related network-forming coordination complexes have been studied. Two novel thermodynamically stable pseudo-polymorphic solvated rhodium chloro compounds, [cis-RhCl(4)(DMSO-κS)(2)K](n), 1, and [cis-RhCl(4)(DMSO-κS)(2)K·3H(2)O](n), 2, and one metastable compound [trans-RhCl(4)(DMSO-κS)(2)K·0.25H(2)...

Structures of three mixed solvates of copper halides: CuBr2·DX·2H2O, CuBr2·2DX·2H2O, and CuCl2·2DX·2H2O (DX is 1,4-dioxane) has been determined by the method of XRD on single crystals. The entry of both solvents into the first coordination sphere of the copper ion was proved. In spite of analogous composition, CuHlg2·2DX·2H2O solvates have differen...

Structures of copper dihalide solvates with dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) were determined by XRD single crystal analysis. The existence of two DMSO solvates with CuBr2, but only one with CuCl2, was attributed to a lower Cu-Br bond strength in comparison with Cu-Cl, and, as a consequence, by its easier breaking to form a...

Absorption spectra of NR4Br-H2O and CoBr2-NR4Br-H2O (R = Et, Bu) aqueous solutions were measured within the range of 1000–25000 cm−1, and the influence of tetraalkylammonium cations on the equilibrium between cobalt octahedral and tetrahedral complexes was revealed. The specificity of hydration interactions in solutions under study in various conce...

By the hydration of MVO(SeO4)(2) with saturated water vapors at room temperature a series of isostructural complex compounds of vanadium(V) of the composition M[VO2(SeO4)(H2O)(2)]⋅H2O (K, Rb, NH4) are synthesized and their physicochemical properties are studied. Based on the X-ray and neutron diffraction data, it is found that their crystal structu...

Solubility in the ternary systems MgBr2-NR4Br-H2O (R = Me, Et, Bu) at 25°C was determined by the isothermal saturation method. A comparative analysis of phase diagrams was fulfilled. The results obtained were interpreted in the context of competition between hydration and association processes in water-salt systems. The structure of double salts NM...

Results of an experimental research of phase equilibrium in ternary systems MX2-NR4X-H2O [M = Cd(II), Cu(II), Co(II), Mg(II); X = Cl, Br; R = Me, Et, Bu] at 25°C were reported. A comparative analysis of compositions of solid compounds and regions of their crystallization, which are equilibrium with liquid phase, was conducted. An effect of hydratio...

The two dimethyl sulfoxide solvated rhodium(III) compounds, [Rh(dmso-κO)(5)(dmso-κS)](CF(3)SO(3))(3) (1 & 1* at 298 K and 100 K, respectively) and [Rh(dmso-κO)(3)(dmso-κS)(2)Cl](CF(3)SO(3))(2) (2), crystallize with orthorhombic unit cells in the space group Pna2(1) (No. 33), Z = 4. In the [Rh(dmso)(6)](3+) complex with slightly distorted octahedral...

Solubility of the ternary systems M-NEt4Cl-H2O (M = Cd, Cu, Co) at 25°C was determined by the method of isothermal saturation. Compositions and fields of crystallization of solid compounds in equilibrium with a liquid phase were determined. Changes in the processes of hydration, association of tetraethyl ammonium salts, and acido-complex formation...

The solubility diagrams in ternary MBr2-NR4Br-H2O systems (M = Cd, Co; R = Me, Et, Bu) at 25°C were determined by isothermal saturation. The composition and crystallization range of solid compounds occurring in equilibrium with the liquid phase were found. The effects of ion hydration, association of tetraalkylammonium salts, and complex formation...

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The crystalline structures of four tetraethylammonium salts, [Et4N]CdBrP3, [Et4N]Cd2Br5, [Et4N]2CoBr4, and [Et4N]2CuBr4 were determined by X-ray analysis of their single crystals. The CdBr x 2 − x anions in the examined salts are linked to polymeric chains, and the coordination number of cadmium ion is 5 or 6. The d-metal ion in the copper and coba...

Mid-infrared, far-infrared, and Raman vibrational spectroscopic studies were combined with density functional theory (DFT) calculations and normal coordinate force field analyses for N,N′-dimethylurea (DMU), N,N,N′,N′-tetramethylurea (TMU), and N,N′-dimethylpropyleneurea (DMPU: IUPAC name 1,3-dimethyltetrahydropyrimidin-2(1H)-one). The equilibrium...

A solution-solid equilibrium in ternary water-organic systems CuCl2-L-H2O (L = dimethyl sulfoxide, N,N-dimethyl formamide, and acetonitrile) at 25°C was studied. The expansion of crystallization branches of individual solvates CuCl2·xL varies in parallel to the donor power of organic solvents. The existence of the mixed crystal-solvates CuCl2·2H2O·...

The solubility in the CuBr2-NR4Br-H2O (R = Me, Et, n-Bu) ternary systems at 25°C was determined by the isothermal saturation method. Comparative analysis of the phase equilibria diagrams was done. The results obtained were interpreted in terms of the competition of two processes, association of tetraalkylammonium salts and copper(II) complex format...

The strongly hydrogen bonded species (CH3)2SO...H3O+ formed in concentrated hydrochloric acid displays a new low energy feature in its sulfur K-edge X-ray absorption near edge structure (XANES) spectrum. Density Functional Theory-Transition Potential (DFT-TP) calculations reveal that the strong hydrogen bonding decreases the energy of the transitio...

The physical properties of the family of cyclotetravanadates A2M(VO3)4, where A=Na,Ag and M=Ca,Sr, have been studied by means of x-ray powder diffraction, neutron diffraction, electron diffraction, infrared, Raman, NMR, photoexcitation and pulse cathode beam excitation, and x-ray photoelectron spectroscopies, and band structure calculations. The di...

Vibrational spectroscopic and force field studies have been performed of 15 related copper(II) chloride and copper(II) bromide compounds, including hydrated salts crystallizing in ternary aqueous systems with alkali and ammonium halides. For halocuprates with distorted octahedral coordination characteristic stretching Raman wavenumbers, correspondi...

Sulfur K-edge X-ray absorption near-edge structure (XANES) spectra have been recorded and the S(1s) electron excitations evaluated by means of density functional theory-transition potential (DFT-TP) calculations to provide insight into the coordination, bonding, and electronic structure. The XANES spectra for the various species in sulfur dioxide a...

The octakis(DMSO) (DMSO = dimethylsulfoxide) neodymium(III), samarium(III), gadolinium(III), dysprosium(III), erbium(III), and lutetium(III) iodides crystallize in the monoclinic space group P21/n (No. 14) with Z = 4, while the octakis(DMSO) iodides of the larger lanthanum(III), cerium(III), and praseodymium(III) ions crystallize in the orthorhombi...

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The new crystalline compounds Tl2Ni(CN)4 and Tl2Pd(CN)4 were synthesized by several procedures. The structures of the compounds were determined by single-crystal X-ray diffraction. The compounds are isostructural with the previously reported platinum analogue, Tl2Pt(CN)4. A new synthetic route to the latter compound is also suggested. In contrast t...

The solubility of d-metal halides in MCl2-M′Cl2-H2O systems with competitive complex formation at 25°C was discussed. The role of complex formation and hydration was traced. As the stability constants become closer to each other, the salting-in regions in the crystallization braches of both chlorides disappear.

The effect of the oxidation state of the metal on the solubility was analyzed using the example of CuClx-MCl-H2O (x = 1, 2; M = Li-Cs, NH4) ternary systems. The prevalence of acido complex formation is responsible for an essential similarity of the solubility The effect of the oxidation state of the metal on the solubility was analyzed using the ex...

Solubility in the ternary system CuCl-NH4Cl-H2O at 25°C was determined by the method of isothermal lifting of oversaturation. A comparative analysis of solubility in this system and the previously studied systems CuCl-MCl-H2O (M+ = Li+, Na+, K+, Cs+) was made. The results obtained were interpreted in terms of competition between hydration, associat...

The experimental Raman vibrational spectrum of the 5.94 m water solution of the beryllium(II) chloride has been acquired. Theoretical frequencies, infrared and Raman intensities of the vibrational spectrum of the beryllium cation tetrahydrate have been calculated by means of quantum chemical approach. The peaks of the experimental spectrum have bee...

Infrared (IR), far-infrared (far-IR) and Raman spectra have been recorded of the hydrate