Bis(2,4,6‐trimethylphenyl)tellurium(IV) Dicyanide: the First Crystal Structure for a Tellurium Cyanide of the Type R2Te(CN)2

The reaction of Mes₂TeF₂ (Mes = 2,4,6‐trimethylphenyl) with trimethylsilyl cyanide yields the corresponding tellurium(IV) dicyanide Mes₂Te(CN)₂. Isolation of suitable crystals allows the determination of the first crystal structure of a compound of the type R₂Te(CN)₂.     

Synthesis and properties of sulfur cyanide trifluoride,SF3CN,sulfur dicyanide difluoride,SF2(CN)2, and sulfinyl cyanide fluoride,FS(O)CN

Sulfur cyanide trifluoride, SF₃CN, and sulfur dicyanide difluoride, SF₂(CN)₂, have been prepared by metathesis between sulfur tetrafluoride, SF₄, and trimethyl silyl cyanide, (CH₃)₃SiCN, at – 30°C. Treatment of SF₃CN with freshly sublimed selenium dioxide, SeO₂, lead to sulfinyl cyanide fluoride, FS(O)CN. IR, Raman, ¹⁹F-NMR, uv and mass spectra of the novel compounds are presented as well as some physical and chemical properties.     

Synthesis and structure of tetra- and triphenylbismuth arenesulfonates

Tetraphenylbismuth arenesulfonates were synthesized by the reaction of pentaphenylantimony of-bismuth with triphenylbismuth bis(arenesulfonates). Triphenylbismuth bis(arenesulfonates) were synthesized by the reaction of triphenylbismuth with arenesulfonic acids in the presence of hydrogen peroxide. The crystal structures of the tetraphenylbismuth 2,5-dimethylbenzenesulfonate crystal hydrate (1), tetraphenylbismuth 3-carboxy-4-hydroxybenzenesulfonate (2), and triphenylbismuth bis(2,5-dimethylbenzenesulfonate) (3) were determined by X-ray diffraction analysis. The Bi atom in1 has a tetrahedral coordination (bond angles vary from 106.6(6) to 111.9(10)^o). The Bi coordination observed in2 is intermediate between tetrahedral and trigonal-bipyramidal, and that in structure3 is trigonal-bipyramidal, with the oxygen atoms in the axial positions. The Bi−O bond lengths are 2.19(2) and 2.27(2) Å. In the crystal of2, the anions form an infinite hydrogen-bonded chain. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2350–2354, December, 1999.     

Synthesis and structure of 2,4,6-tribromophenoxytetraphenylbismuth

Four new complexes of pentavalent bismuth are synthesized: Ph₃Bi[OC₆H₂(Br₃-2,4,6)]₂, Ph₃Bi[OC₆H₂(Cl₃-2,4,6)]₂, Ph₄BiOC₆H₂(Br₃-2,4,6), and Ph₄BiOC₆H₂(Cl₃-2,4,6). Tetraphenylbismuth aroxides are produced by the disproportionation reaction of ligands from pentaphenylbismuth and triphenylbismuth diaroxides in toluene or from pentaphenylbismuth and phenol. Triphenylbismuth diaroxides are synthesized from phenol, triphenylbismuth, and hydrogen peroxide taken at a molar ratio of 2 : 1 : 1, respectively, in diethyl ether. According to the X-ray diffraction data, the bismuth atom surrounding in 2,4,6-tribromophenoxytetraphenylbismuth has the configuration of a trigonal bipyramid with the aroxyl ligand in the axial position. The Bi-C and Bi-O bond lengths are 2,184, 2.190, 2.234, and 2.514 Å, respectively, and the equatorial CSbC angles are equal to 111.4°, 121.3°, and 121.3°.Translated from Koordinatsionnaya Khimiya, Vol. 30, No. 12, 2004, pp. 935–938.Original Russian Text Copyright © 2004 by Sharutin, Egorova, Tsiplukhina, Gerasimenko, Pushilin.     

A simple method for preparation of Zinc,Cadmium, Mercuric and Cobalt Acetylacetonates

By mixing ZnO, CdO HgO, CoO and Co₃O₄, respectively, with acetylacetone at room temperature, in the presence of the proper solvents, the corresponding metal acetylacetonates were obtained directly in good yields. The molecular structure was confirmed on the basis of UV spectroscopy, melting points, metal analysis and X-ray powder photography.     

Triphenylbismuth bis(3,4-dimethylbenzenesulfonate): Synthesis and structure

Triphenylbismuth bis(3,4-dimethylbenzenesulfonate) Ph₃Bi(OSO₂C₆H₃Me_2-3,4)₂ (I) has been synthesized by the reaction between triphenylbismuth and 3,4-dimethylbenzenesulfonic acid in the presence of tert-butylhydroperoxide (1: 2: 1 mol) in ether. The bismuth atom in complex I has a trigonal bipyramidal coordination to arenesulfonates substituents in axial positions (axial OBiO angle, 173.99(8)°; equatorial CBiC angles, 106.94(11)°, 112.24(11)°, 140.77(11)°). The Bi?C distances are 2.189(3), 2.192(3), and 2.197(3) Å; the Bi?O distances are 2.284(2) and 2.301(2) Å. Some intramolecular contacts are observed between the central atom and the oxygen atoms of sulfonate groups at the maximum equatorial angle (Bi···O 3.122(3), 3.189(4) Å).     

Study of homo- and cross-coupling competition in the reaction of triarylbismuth(V) dicarboxylates with methyl acrylate in the presence of a palladium catalyst

Triarylbismuth(V) derivatives Ar₃Bi(O₂CR)₂ (Ar = Ph, m-Tol, p-Tol; R = H, Me, Et, n-Bu, t-Bu, n-C₅H₁₁, CF₃, CH₂Cl, CCl₃, Ph) were prepared in good to excellent yields by reaction of Ar₃Bi with equimolar amounts of t-BuOOH in the presence of an acid. These compounds were tested in the C-arylation reaction of methyl acrylate, as a model substrate, in the presence of palladium catalyst (4 mol%). It was found that triphenylbismuth dicarboxylates are very active phenylating agents under mild conditions (20 °C). The effect of the carboxylic group, the effect of the nature of the palladium catalyst and the effect of oxygen on the reactivity of the organobismuth compounds and on the selectivity of the C-arylation reaction were studied. Methyl cinnamate, the C-phenylation product, and biphenyl, the homo-coupling by-product, were obtained in all cases. Triphenylbismuth divalerate Ph₃Bi(O₂CBu)₂ is the most reactive compound among the triphenylbismuth dicarboxylates studied.     

Thermal ring-opening reaction of N-polynitromethyl tetrazoles: facile generation of nitrilimines and their reactivity

Thermal ring-opening reaction of N-(R-dinitromethyl)-5-nitrotetrazoles (R=NO₂, F, Cl) yielded highly reactive N-(R-dinitromethyl)-nitrilimine intermediates under mild conditions. These species underwent facile and regiospecific reaction with nitriles and acetylenes to afford the corresponding nitrotriazoles and nitropyrazoles in 50-90% yields. Treatment of N-(chlorodinitromethyl)-5-nitrotetrazole with the excess of azide led to a unique compound with the molecular formula C₂N₁₄. Based on the analytical data, it was assigned a structure of diazidomethylenecarbonohydrazonic diazide.     

A comparative study of triphenylamine,triphenylphosphine, triphenylarsine,triphenylantimony and triphenylbismuth as ligands in the rhodium-catal yzed hydroformylation of 1-dodecene

Triphenylarmine, triphenylphosphine, triphenylarsine, triphenylantimony and triphenylbismuth were evaluated on the basis of olefin to aldehyde conversion, and also on the basis of the normal/iso (n / i) product ratio, as ligands in the rhodium-catalyzed hydroformylation of 1-dodecene. Two series of reactions were conducted which differed only in total reaction time (120 minutes vs 135 minutes) and in the ligand/rhodium ratio (60:1 vs 300:1). Both reactions series employed 35 grams of 1-dodecene, a 176 ppm rhodium charge, 100 psig of 1:1 H₂ / CO, and a reaction temperature of 90° C. In the 60:1 vs 330:1 reaction series, triphenylamine gave olefin conversions and n / i ratios of 2.0%, 2.0 vs 5.8%, 1.8; triphenylphosphine gave 95%, 4.4 vs 86.9%, 8.7; triphenylarsine gave 58%, 3.1 vs 85.8%, 3.5; triphenylantimony gave 13.0%, 6.1 vs 3.5%, 9.1 respectively. Triphenylbismuth failed to promote hydroformylation in both reaction series. These data demonstrate that regiospecificity, as measured by the n / i product ratio, varies inversely to increased ligand basicity.     

Products of the Radiation-Chemical and Thermal Decomposition of Mercury Fulminate

The products of the radiation-chemical and thermal decomposition of mercury fulminate were examined by IR spectroscopy and X-ray diffraction analysis. Upon radiolysis to 20% conversion, the fulminate ion underwent decomposition (G (decomposition) = 20 molecule/100 eV) with the formation of HgO (G = 9 ± 1 molecule/100 eV), CN^– ions, and CO₂. The final solid products of the radiolysis are Hg(CNH)₂, a cyanide complex, the mercury carbonate oxide HgCO₃ · 3HgO, the mercury cyanide oxide Hg(CN)₂ · HgO, and paracyanogen (CN)_n. In the thermolysis, the final solid products of decomposition are the mercury carbonate oxide HgCO₃ · 2HgO, a cyanide complex, and the cluster Hg_nC_mN_oO_p.     

Synthesis and Structure of Triphenylbismuth Dinitrite and Dinitrate

Triphenylbismuth dinitrate (I) and triphenylbismuth dinitrite (II) were synthesized through the reaction of triphenylbismuth dichloride with silver nitrate in an acetone–alcohol (1 : 1) solution or with sodium nitrite in acetone–water (1 : 1) solution. According to X-ray diffraction data, bismuth atoms in Iand II have a distorted trigonal bipyramidal configuration. The intramolecular Bi···N(1,2) contacts in II (2.997(3), 2.982(4) Å) are shorter than similar contacts in I(3.038(3), 3.031(3) Å); the Bi···O(2,4) distances in II and Bi···O(2,5) distances in I are equal to 2.879(2), 2.913(3) and 2.893(3), 2.896(3) Å, respectively.     

半晶化双螺旋介孔MnO2的合成和电化学性质

Mesoporous silica KIT-6 has novel three-dimensional gyroidal channel structure, space group of 1a-3d, and ordered tunable pores up to 10 nm. In this paper, such mesostructured silica was employed as hard template to prepare semicrystalline gyroidal mesoporous MnO2. The structure was investigated by XRD, TEM and HRTEM, and found to be of high quality 1a-3d symmetry, in good accordance with the template structure. The material has a BET surface of 118 m2·g^-1 and pore volume of 0.35 cm3·g^- 1 after eliminating template. Mesoporous MnO2 has shown good electrochemical property as supercapacitor material in 1 mol·L^-1 Na2SO4 and 1 mol·L^-1 LiClO4 solutions, but interesting pseudocapacitance behavior was observed in the case of 6 mol·L^-1 KOH. It was found that mesoporous MnO2 performed stable reversible electrochemical behavior with capacitance of 220 F·g^-1 in a potential range of -0.1-0.55 V vs. Hg/HgO in alkaline solution, demonstrating that it is a promising novel electrode material for the fabrication of electrochemical capacitors.     

Effect of microheterogeneous environments of CTAB,Triton X-100, and Tween 20 on the oxidative degradation of d-fructose by nanoparticles of MnO2

The kinetics of the oxidative degradation of d -fructose by nanoparticles of MnO₂ has been studied in dilute sulfuric acid medium and also in the presence of surfactants of cetyl trimethyl ammonium bromide (CTAB), Triton X-100 (TX-100), and Tween 20. Amorphous nanoparticles of MnO₂ in the form of spherical particulates of size 50–200 nm, as detected by a transmission electron microscope, have been found to exist, supported on two-dimensional gum acacia sheets. The reaction is first order in MnO₂ but complex order with respect to fructose and H⁺. The reaction is inhibited due to adsorption of reaction products on the surface of MnO₂ nanoparticles. The reaction takes place through an intermediate complex formation between β-d -fructopyranose and protonated MnO₂. A one-step two-electron transfer reaction ultimately leads to the formation of an aldonic acid and formic acid. The entropy of activation plays the key role for the reaction in the absence of surfactants. In the surfactant-mediated reaction, partitioning of both the reactants takes place between the aqueous and micellar pseudophases and reaction occurs following Berezin's model. Binding of fructose with the surfactants in the Stern/palisade layer takes place through the ion–dipole interaction and H-bonding while protonated MnO₂ remains at the outer side of the Stern/palisade layer within the micelle. Both the enthalpy and entropy changes associated with the fructose–water interaction, fructose–micelle interaction, and micelle–water interaction finally control the fructose–micelle binding.     

Kinetics and mechanism of free-surface vaporization of zinc, cadmium and mercury oxides analyzed by the third-law method

On the basis of critical comparison of experimental and theoretical values of the E parameter and investigation of the retardation effect of oxygen on the evaporation rate of ZnO, CdO and HgO, it was concluded that the dissociative evaporation of ZnO and HgO proceeds with releasing of atomic oxygen (O) as a primary product of decomposition. By contrast, the mechanism of dissociative evaporation of CdO corresponds to the equilibrium reaction with releasing of molecular oxygen (O₂) as a primary product of decomposition. As was shown, this difference in mechanisms is not related with interatomic OO distances in these oxides. From the analysis of crystal structure for 12 different oxides, which evaporate with releasing of atomic oxygen, and for 13 compounds, which evaporate with releasing of molecular oxygen, it was revealed that the first mechanism is observed for all oxides with the cubic crystal structure. It was proposed that a decisive role in this difference belongs to a local symmetry in the position of O atoms.     

[3+2] Fragmentation of a Pentaphosphido Ligand by Cyanide

The activation of white phosphorus (P₄) by transition‐metal complexes has been studied for several decades, but the functionalization and release of the resulting (organo)phosphorus ligands has rarely been achieved. Herein we describe the formation of rare diphosphan‐1‐ide anions from a P₅ ligand by treatment with cyanide. Cobalt diorganopentaphosphido complexes have been synthesized by a stepwise reaction sequence involving a low‐valent diimine cobalt complex, white phosphorus, and diorganochlorophosphanes. The reactions of the complexes with tetraalkylammonium or potassium cyanide afford a cyclotriphosphido cobaltate anion 5 and 1‐cyanodiphosphan‐1‐ide anions [R₂PPCN]^? ( 6‐R ). The molecular structure of a related product 7 suggests a novel reaction mechanism, where coordination of the cyanide anion to the cobalt center induces a ligand rearrangement. This is followed by nucleophilic attack of a second cyanide anion at a phosphorus atom and release of the P₂ fragment.     

Synthesis and structure of triphenylbismuth bis(pentachlorobenzoate)

Triphenylbismuth bis(pentachlorobenzoate) has been synthesized by the reaction between triphenylbismuth and pentachlorobenzoic acid in the presence of hydrogen peroxide in ether. According to X-ray diffraction data, the bismuth atoms in two crystallographically independent molecules (A and B) have a distorted trigonal bipyramidal coordination. The OBiO and CBiC angles between axial and equatorial substituents are 171.7(3)°, 173.6(3)°, and 105.3(4)°–146.9(4)°. The Bi-O and Bi-C bond lengths are 2.291(8)–2.315(8) and 2.197(11)–2.204(10) Å, respectively. The Bi…O(=C) distances are 2.843(10)–2.857(11) Å.     

Reaction of Triphenylbismuth Bis(arenesulfonates) with Triphenylstibine

Tetraphenylantimony arenesulfonates and diphenylbismuth arenesulfonates were prepared by reaction of triphenylbismuth bis(arenesulfonates) with triphenylstibine in toluene at 25°C. The crystal and molecular structure of diphenylbismuth 2,4-dimethylbenzenesulfonate was studied by single crystal X-ray diffraction. The molecules of the compound in the crystal form chains of Ph₂BiOSO₂C₆H₃Me₂-2,4 fragments linked with oxygen atoms of the sulfo group of the bridging arenesulfonate ligand.     

A new method for the potentiometric determination of lead with alkaline permanganate

A new method for the estimation of lead, based on its oxidation from the bivalent to the quadrivalent state by alkaline permanganate has been devised. The reaction takes place so rapidly in the presence of a mixture of ZnO and HgO that it can be followed potentiometrically. Oxidation of sodium plumbite with KMn0₄ leads to the formation of PbO and MnO. Reduction of KMnO4 with Pb⁺² ions or with sodium plumbite proceeds almost quantitatively in 2.5N NaOH in the absence of Ba⁺² ions and in 1–1.5N NaOH in the presence of these ions. Under these conditions Pb⁺² Pb⁺¹ and Mn0₄ MnO₄^-2, provided that the lead solution is not added too rapidly.     

Effect of ionic and non-ionic surfactants on the reduction of water soluble colloidal MnO<Subscript>2</Subscript> by glycolic acid

Kinetics of the redox reaction between colloidal MnO₂ and glycolic acid have been studied spectrophotometrically by monitoring the decay in the absorbance of colloidal MnO₂ in absence and presence of surfactants. Anionic sodium dodecyl sulfate has no effect, non-ionic Triton X-100 catalyzed the reaction and experiments were not possible in presence of cationic cetyltrimethylammonium bromide due to the precipitation of MnO₂.The reaction followed the same type of kinetic behavior, i.e., fractional-, first- and fractional-order dependencies, respectively, in [glycolic acid], [MnO₂] and [H⁺ ] in both the media. Effects of gum arabic and manganese(II) have also been studied and discussed. Mechanisms in accordance with the experimental data are proposed for the reaction.     

Effect of synthetical conditions, morphology, and crystallographic structure of MnO2 on its electrochemical behavior

Manganese dioxide nanostructures have been synthesized by hydrothermal synthetical method. The crystallographic structure, morphology, and electrochemical properties of obtained MnO₂ are examined by XRD, TEM, cyclic voltammetry, and galvanostatic charge–discharge tests. The results showed that the electrochemical properties of MnO₂ were strongly affected by the crystallographic structure and morphology. The controlling crystallographic structure of MnO₂ can be obtained by altering the molar ratio of KMnO₄/MnSO₄. The morphology was affected by the hydrothermal dwell time and temperature. The optimal synthetic conditions are as follows: the initial molar ratio of KMnO₄/MnSO₄ is 3:1, the reaction lasts 2 h at 120 °C, and the filling factor is 90%. In these prepared conditions, the MnO₂ with the maximum specific capacitance of 259 F g⁻¹ can be obtained. Prepared δ-MnO₂ has a good layer structure and exhibits nanoflower morphology. The XRD studies show that the crystalline degree of this sample is lower, and the average grain size is about 8.3 nm. These results indicate that the product may have potential applications in areas such as electrode materials of supercapacitor and other new storing energy system.