Destruction of 2,4 Dichlorophenol in an Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

The processes of degradation of 2,4-dichlorophenol (2,4-DCP) under the action of atmospheric pressure of dielectric barrier discharge (DBD) in oxygen were studied. It was shown that the degradation of 2,4-DCP proceeds efficiently. Degree of decomposition reaches 90%. The degradation kinetics of 2,4-DCP obeys the formal first-order kinetic law on concentration of 2,4-DCP. The effective rate constants depend weakly on the experimental conditions and are equal to ~0.2 s^?1. Based on experimental data, the energy efficiency of decomposition of 2,4-DCP was determined. Depending on the conditions, the energy efficiency was in the range of (8–90) × 10^?3 molecules per 100 eV. The composition of the products was studied by gas chromatography (GC), gas chromatography–mass spectrometry (GC–MS), energy-dispersive X-ray spectroscopy (EDX), attenuated total reflection-fourier transform infrared (ATR-FTIR) spectroscopy, electron spin resonance (ESR) spectroscopy and UV/Visible spectroscopy. It was shown that about ~20% of 2,4-DCP is converted to CO₂, while the other part forms an organic film on the reactor wall. The substance formed is close to the carboxylic acids in chemical composition and exhibits electrical conductivity and paramagnetic properties. Almost all of the chlorine contained in the 2,4-DCP is released into the gas phase. The active species of the afterglow react with liquid hexane, forming the products of its oxidation. Some assumptions regarding the pathway of the process are discussed.     

Tantalum Dimethyldithiocarbamate Complexes

The reaction of Ta(NMe₂)₅ with CS₂ gave the tantalum(V) dimethyldithiocarbamate complex [Ta(^MeDtc)₄](^MeDtc) (I). An ionic structure of the complex with a dodecahedral coordination of the tantalum atom was determined for toluene (I · Tol) and THF (I · THF) solvates by X-ray diffraction (CCDC no. 1544283 and no. 1544284, respectively). The reaction of I with CH₂Cl₂ leads to exchange of the outersphere anion to give the known complex [Ta(^MeDtc)₄]Cl (II). The cyclic voltammogram of II in CH₃CN exhibits a quasi-reversible transition at E _1/2 =–0.735 V corresponding to the Ta^V/Ta^IV pair.     

Synthesis and structure of trimethylantimony dimethacrylate

The reaction of trimethylantimony with methacrylic acid in the presence of tert-butyl hydroperoxide gave trimethylantimony dimethacrylate Me₃Sb(O₂CCMe=CH₂)₂ whose structure was confirmed by elemental analysis and IR, ¹H and ¹³C NMR, and mass spectra. According to the X-ray diffraction data, the title compound is a trigonal–bipyramidal antimony complex with three methyl group in the pyramid base and two methacrylate ligands in the apices.     

Spatial interaction of jets propagating in an accompanying supersonic flow

A numerical method of calculating a three-dimensional laminar supersonic underexpanded jet escaping into an accompanying supersonic flow is developed. The simplified Navier-Stokes equations for a steady-state three-dimensional flow are employed. Numerical calculations are carried out for several cases relating the outflow of jets from a four-nozzle assembly into an accompanying supersonic flow, and a number of the characteristics of three-dimensional flows of this kind are presented.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 88–93, November–December, 1972.     

Mixed-ligand cluster [Mo3S4(Dtp)2(μ-AcO)Cl(Me2Bipy)]: Synthesis and structure

Mixed-ligand cluster [Mo₃S₄(Dtp)₂(μ-AcO)Cl(Me₂Bipy)] · CHCl₃ (I · CHCl₃), where Dtp is (EtO)₂PS₂, was synthesized by the reaction of the molybdenum aqua complex [Mo₃S₄(H₂O)₉]⁴⁺ with 4,4′-dimethyl-2,2′-bipyridine (Me₂Bipy) and phosphorus sulfide (P₄S₁₀) in ethanol followed by chromatographic separation on silica gel and crystallization in the presence of acetic acid. The crystal structure of I · CHCl₃ was determined by X-ray diffraction analysis. The synthesized compound was characterized by the IR and NMR spectra and elemental analysis. The electronic structure of the synthesized compound was established, and its electrochemical behavior in a solution was studied.     

Decyclization of chiorocyclohexanone hydroperoxides under the action of ferrous salts

The decomposition of 2-chloro-, 2,2-dichloro-, and 2,6-dichloro-substituted cyclohexanone hydroperoxides on treatment with ferrous chloride and sulfate to give chloro-substituted aliphatic acids was investigated. A method for the synthesis of 2,6,6-trichlorohexanoic and 2,6,7,11-tetrachlorododecane-1,12-dioic acids was elaborated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 143–146, January, 1996.     

Magnetorefractive effect in magnetic nanocomposites

The magnetorefractive effect in ferromagnetic metal-insulator granular nanostructures (CoFeZr)-SiO_n, Co-Al-O, FeSiO_n, and (CoFe)-(Mg-F) is investigated in the infrared spectral region in a wavelength range from 5 to 20 μm. The magnitude of the effect varies from 0.1 to 1.5% for different nanocomposites and strongly depends on the frequency of light and magnetoresistance. It is shown that the reflection coefficient changes in a magnetic field not only due to the magnetorefractive effect, but also due to the even magnetooptical effect. Simple relations describing this effect are given for the case when the reflection from the substrate is insignificant and in the case of a three-layer (insulator-film-substrate) system. The expression for the frequency dependence of the magnetorefractive effect in nanocomposites is derived and its features in the case of high-frequency spin-dependent tunneling are analyzed.     

Structure and thermal properties of a tungsten sulfide cluster with thiourea ligands

The reaction of [W₃S₄(H₂O)₉]⁴⁺ with thiourea (tu) in hydrochloric acid produces a new cluster complex [W₃S₄(tu)₈(H₂O)]Cl₄?2H₂O containing coordinated thiourea. The complex is characterized by elemental analysis, thermogravimetry, IR, NMR, UV-Vis spectroscopy, and mass spectrometry. The crystal structure is determined by X-ray analysis. The thermal decomposition of [W₃S₄(tu)₈(H₂O)]Cl₄?2H₂O on heating from 20°С to 700°С in He gives WS₂, identified by the X-ray diffraction pattern. DFT calculations for [W₃S₄(tu)₈(H₂O)]⁴⁺ show that HOMO has a comparable contribution from metal- and ligand-centered atomic orbitals.     

Novel tailoring reaction for two adjacent coordinated nitriles giving platinum 1,3,5-triazapentadiene complexes

The tailoring reaction of the two adjacent nitrile ligands in cis-[PtCl(2)(RCN)(2)] (R = Me, Et, CH(2)Ph, Ph) and [Pt(tmeda)(EtCN)(2)][SO(3)CF(3)](2) (8.(OTf)(2); tmeda = N,N,N',N'-tetramethylethylenediamine) upon their interplay with N,N'-diphenylguanidine (DPG; NH=C(NHPh)(2)), in a 1:2 molar ratio gives the 1,3,5-triazapentadiene complexes [PtCl(2){NHC(R)NHC(R)=NH}] (1-4) and [Pt(tmeda){NHC(Et)NHC(Et)NH}][SO(3)CF(3)](2) (10.(OTf)(2)), respectively. In contrast to the reaction of 8.(OTf)(2) with NH=C(NHPh)(2), interaction of 8.(OTf)(2) with excess gaseous NH(3) leads to formation of the platinum(II) bis(amidine) complex cis-[Pt(tmeda){NH=C(NH(2))Et}(2)][SO(3)CF(3)](2) (9.(OTf)(2)). Treatment of trans-[PtCl(2)(RCN)(2)] (R = Et, CH(2)Ph, Ph) with 2 equiv of NH=C(NHPh)(2) in EtCN (R = Et) and CH(2)Cl(2) (R = CH(2)Ph, Ph) solutions at 20-25 degrees C leads to [PtCl{NH=C(R)NC(NHPh)=NPh}(RCN)] (11-13). When any of the trans-[PtCl(2)(RCN)(2)] (R = Et, CH(2)Ph, Ph) complexes reacts in the corresponding nitrile RCN with 4 equiv of DPG at prolonged reaction time (75 degrees C, 1-2 days), complexes containing two bidentate 1,3,5-triazapentadiene ligands, i.e. [Pt{NH=C(R)NC(NHPh)=NPh}(2)] (14-16), are formed. Complexes 14-16 exhibit strong phosphorescence in the solid state, with quantum yields (peak wavelengths) of 0.39 (530 nm), 0.61 (460 nm), and 0.74 (530 nm), respectively. The formulation of the obtained complexes was supported by satisfactory C, H, and N elemental analyses, in agreement with FAB-MS, ESI-MS, IR, and (1)H and (13)C{(1)H} NMR spectra. The structures of 1, 2, 4, 11, 13, 14, 9.(picrate)(2), and 10.(picrate)(2) were determined by single-crystal X-ray diffraction.     

A Novel Tantalum Cluster Chalcohalide Ta4S1.5Se7.5I8

Single crystals of Ta₄S_1.5Se_7.5I₈ are obtained by heating Ta, S, Se and I₂ at 300 °C in 4.0:1.0:8.0:4.4 molar ratio. The structure was determined by X-ray analysis and consists of molecular clusters [Ta₄(μ₄-S)(μ₂-Q_axSe_eq)₄I₈] (Q ≈ Se_0.87S_0.13). The tantalum atoms form a square with long Ta…Ta distances (3.26–3.32 Å), with four dichalcogenide ligands bridging the Ta–Ta edges and a sulfur atom capping the square. Each Ta atom has two terminal iodine atoms. Raman spectroscopy study shows the presence of the characteristic absorption band at 396 cm^?1 which is due to the Ta₄–μ₄-S vibrations. Cyclic voltammetry shows that Ta₄S_1.5Se_7.5I₈ in solid state undergoes quasi-reversible one-electron oxidation which is metal-centered.