S. V. Volkov

The first nonaselenium ring.

The reaction of Se(2)Cl(2) with RhCl(3).4H(2)O at 100 degrees C gives dirhodium nonaselenium hexachloride Rh(2)Se(9)Cl(6). The structure exhibits the first Se(9) ring observed to date.

Electrolytic Generation of Nano-Scale Carbon Phases with Framework Structures in Molten Salts on Metal Cathodes

An electrochemical study of mechanisms of electrodeposition of carbon solid phases from halide melts (Na,K|Cl; Na,K,Cs|Cl), saturated with carbon dioxide under an excessive pressure of up to 1.5 MPa, has been carried out in the temperature range 550 - 850 °C by cyclic voltammetry. It has been found that the cathode process occurs in three steps at sweep rates of less than 0.1 Vs−1, and its electrochemical-chemical-electrochemical (ECE) mechanism is suggested. It has furthermore been found that cathodic deposits contain nano-sized carbon particles of different forms and structure: blocks of amorphous carbon, crystalline graphite, carbon nanotubes (CNT), and nanofibres. The outer diameter of the tubes is 5 - 250 nm, and the internal diameter is 2 - 140 nm. A correlation between the product structure and yield against electrolysis conditions and regimes has been established.

Osmium thioselenochloride Os 2 S 6 Se 2 Cl 8 : Synthesis, cluster isolation, and structure

The quaternary thioselenochloride complex Os2S6Se2Cl8 (I) was obtained by a reaction of OsO4 with a solution of Se in S2Cl2 at 100°C and identified by combination of X-ray diffraction (polycrystalline approach) and cluster framework isolation. A reaction of complex I with melted 4-cyanopyridine (4-CNPy) at 165°C gave the complex Os2S2Cl4(4-CNPy)4, which confirms the integrity of the binuclear cluster frame-work [Cl2OsS2OsCl2] in complex I.

Catalytic properties of RhSe2/Ga/H-ZSM-5 system in the reaction of glycerol dehydration in the gas phase

Catalytic properties of the RhSe2/Ga/H-ZSM-5 system formed upon thermal treatment of a mechanical mixture of rhodium selenochloride Rh2Se9Cl6 and a gallium-containing zeolite Ga/H-ZSM-5 at 300–340°C in a flow of nitrogen were studied in the course of glycerol dehydration in the gas phase. It was shown that the promotion of Ga/H-ZSM-5 with rhodium selenide RhSe2 makes higher the yield of the target product acrolein.

Synthesis, Structure and Some Catalytic Properties of the New Trinuclear Rhenium Cluster Compound Re3Se3S4Br13

The reaction of Re2O7 with a mixed non-aqueous medium S2Br2+Se2Br2 at 100 °C gives Re3Se3S4Br13: own structure type, Z = 4, space group Pnma – d 9c 5, a = 14.0301(4), b = 17.7909(4), c = 10.8596(3) Å, RI = 0.0491. The crystal structure can be described as a 3D-packing of isolated trinuclear cluster molecular cation-anionic complexes [Re3(µ3-S)(µ-S)3(SeBr2)3Br6]+Br–. This compound displays a high catalytic activity in the hydrogenation of m-nitrobenzoic acid into m-aminobenzoic acid with 93 % yield in 5 % HBr aqueous solution.

Structure of the Os2S2Br4(4-CNPy)4 complex

The interaction of the quaternary thioselenobromide complex Os2S7Se5Br8 prepared by the reaction of OsO4 with a solution of sulfur in Se2Br2 at 100°C with melted 4-CNPy at 165°C leads to the formation of the Os2S2Br4(4-CNPy)4 complex whose structure is determined by single crystal X-ray diffraction.

The complex [{Re3(μ3-S)(μ-S2)3}Br6]Br: a novel method of synthesis and the reaction with KF · HF

A novel high-yielding synthetic route to the triangular cluster complex [{Re3(μ3-S)-(μ-S2)3}Br6]Br was proposed. A reaction of the complex with molten KF · HF gave the cuboid cluster complex K8[{Re4(μ3-S)4}F12][{Re4(μ3-S)3(μ3-O)}F12] · 4H2O containing the earlier un-known heteroleptic cluster core {Re4(μ3-S)3(μ3-O)}8+. The structures of both complexes were confirmed by single-crystal X-ray diffraction.

Complexation of Co(II) with phosphonomethylaminosuccinic acid in solutions

Complexation in the Co(II)-phosphonomethylaminosuccinic acid (H4L) system in aqueous solutions at component ratios of 1 : 1 and 1 : 2 and cCo(II) = 1 × 10−2 mol/L was studied by electronic absorption spectroscopy. The formation of various protonated complexes of the general formula Co(HnL)m(OH)q (n = 3−0; m = 1–2; q = 0–2) was found, and their stability constants and distribution diagrams were calculated. It was demonstrated that the bis complexes have the structure of a distorted octahedron, and the octahedron → tetrahedron rearrangement of the coordination polyhedron occurs in the equimolar complexes at pH > 8.

Crystal structure of osmium selenobromide OsSe2Br12

The crystal structure of the compound OsSe2Br12 obtained by the reaction of OsBr4 with SeBr4 or Se in liquid bromine at 100°C was studied by X-ray powder diffraction. The structure of osmium selenobromide corresponds to a specific type: space group C2/m, a = 14.0464(2) Å, b = 11.05398(14) Å, c = 6.50340(9) Å, β = 112.2645(11)°, Z = 2; RB = 0.03946, Rwp = 0.05403, χ2 = 4.261 for 479 reflections and 53 refinement parameters. The X-ray diffraction analysis confirmed the earlier assumption concerning the cation-anion structure of the compound representing a packing of nearly regular [OsBr6]2− octahedra as anionic complexes and deficient [:SeBr3]+ tetrahedra as cationic complexes in which the missing vertex is occupied by the lone electron pair of selenium.