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Kinetics and Mechanism for the Redox Reaction between Hexaaquathallium(III) and Sulfur Dioxide in Acidic Aqueous Solution

Oxidation of dissolved sulfur dioxide, SO2·nH2O, HSO3– and SO32–, by hexaaquathallium(III) has been studied in acidic aqueous solution with ionic strength 1.0 mol dm–3 at 25 °C. The stoichiometry of the reaction has been determined: [Tl(H2O)6]3++ SO2(aq)+ 2H2O →[Tl(H2O)6]++ HSO4–+ 3H+. The kinetics has been studied by use of stopped-flow spectrophotometry under pseudo-first-order conditions with eOxidation of dissolved sulfur dioxide, SO2·nH2O, HSO3– and SO32–, by hexaaquathallium(III) has been studied in acidic aqueous solution with ionic strength 1.0 mol dm–3 at 25 °C. The stoichiometry of the reaction has been determined: [Tl(H2O)6]3++ SO2(aq)+ 2H2O →[Tl(H2O)6]++ HSO4–+ 3H+. The kinetics has been studied by use of stopped-flow spectrophotometry under pseudo-first-order conditions with e

New Methods for Synthesis of Platinum(II) Dimethyl Sulfide Complexes

Different methods for the synthesis of anionic dimethyl sulfide platinum complexes of the type Q[PtCl3(Me2S)] (Q = triphenylbenzylphosphonium, Ph3PBzl, or tetrabutylammonium, BU4N) and [Pt(mu-Cl)Cl(Me2S)]2 are reported. The compounds Q[PtCl3(Me2S)] were prepared by interaction of [PtCl4]2- with an excess of Me2S in non-aqueous media, reduction of [PtCl5(Me2S)]- with hydrazine sulfate, bridge-split

Kinetics and Mechanism for Manganese-Catalyzed Oxidation of Sulfur(IV) in Aqueous Solution

The kinetics for manganese-catalyzed autoxidation of sulfur(IV) (SO2.nH2O, HSO3-, SO32-) in aqueous solution has been studied spectrophotometrically at 25-degrees-C, 1 < pH < 4, [S(IV)] almost-equal-to 2.3 X 10(-5) M, 1 X 10(-6) M less-than-or-equal-to [Mn(II)] less-than-or-equal-to 1.5 X 10(-3) M, [Mn(III)] less-than-or-equal-to 4 X 10(-8) M, [O2] almost 2.5 X 10(-4) M, and low ionic strength. In

Phenylation of Platinum(II) Thioether Complexes by Tetraphenylborate(III) in Solid State and Nitromethane Solution

Platinum(II) complexes of the type [Pt(thioether)2Cl]+(thioether = dimethyl sulfide, thioxane) are capable of abstracting a phenyl group from the BPh4 counterion with formation of trans[Pt(thioether)2ClPh] compounds. Thermal reactions proceed both in the solid phase and in nitromethane solution at elevated temperature and have preparative importance. Phenylation of the Pt(II) centre also occurs inPlatinum(II) complexes of the type [Pt(thioether)2Cl]+(thioether = dimethyl sulfide, thioxane) are capable of abstracting a phenyl group from the BPh4 counterion with formation of trans[Pt(thioether)2ClPh] compounds. Thermal reactions proceed both in the solid phase and in nitromethane solution at elevated temperature and have preparative importance. Phenylation of the Pt(II) centre also occurs in

Dissociative Reactions to the San Francisco Bay Area Earthquake of 1989

This study systematically evaluated the psychological reactions of a non-clinical population to the October 1989 Bay Area earthquake. Within a week of the earthquake, a checklist of anxiety and dissociative symptoms was administered to a representative sample of approximately 100 graduate students and faculty members from two different institutions in the Bay Area. A follow-up study was conducted

Psychiatric Disorders Among Tortured Bhutanese Refugees in Nepal

The impact of torture on the distribution of psychiatric disorders among refugees is unknown.We surveyed a population-based sample of 418 tortured and 392 nontortured Bhutanese refugees living in camps in Nepal. Trained interviewers assessed International Classification of Diseases, 10th Revision (ICD-10) disorders through structured diagnostic psychiatric interviews.Except for male sex, history o

Psychometric properties of the Stanford Acute Stress Reaction Questionnaire (SASRQ): : A valid and reliable measure of acute stress

A reliable and valid measure is needed for assessing the psychological symptoms experienced in the aftermath of a traumatic event. Previous research suggests that trauma victims typically experience dissociative, anxiety and other symptoms, during or shortly after a traumatic event. Although some of these symptoms may protect the trauma victim from pain, they may also lead to acute stress, posttra

A 3D Digital Approach to Study, Analyse and (Re)Interpret Cultural Heritage : the Case Study of Ayia Irini (Cyprus and Sweden)

This paper focuses on the on-going doctoral research of the writer. Specifically, the topic of this article is on the methodology, the theoretical approach and the first steps of the research. The general aim is the contribution of 3D documentation and the 3D digital approach to the stylistic and typological study of archaeological collections. The study is applied to the collection of the Ayia Ir

Transition Metal Ions in Atmospheric Waters. 4.1 Metal Ion Catalyzed Autoxidation of Dissolved Sulfur Dioxide

The overall kinetics for manganese(II/III) catalyzed autoxidation of dissolved sulfur dioxide has been studied by UV-vis spectrophotometry. A free-radical mechanism has been proposed, and the rate constant for one of the key reactions between manganese(II) and peroxomonosulfate has been determined by pulse radiolysis. Previous literature on manganese catalyzed autoxidation of SO2(aq) has been thor

Structures of Solvated Cations of Palladium(II) and Platinum(II) in Dimethyl Sulfoxide, Acetonitrile and Aqueous Solution Studied by EXAFS and LAXS

X-Ray absorption edge and EXAFS spectra of the solvated cations of platinum(II) in water, dimethyl sulfoxide and acetonitrile and of palladium(II) in dimethyl sulfoxide have been recorded and analyzed. The cations are four-coordinated. Pt-O in Pt(H2O)4(2+) is 2.01(1) angstrom and Pt-N in Pt(CH3CN)4(2+) is 2.00(1) angstrom. The dimethyl sulfoxide solvated cations of both platinum and palladium contX-Ray absorption edge and EXAFS spectra of the solvated cations of platinum(II) in water, dimethyl sulfoxide and acetonitrile and of palladium(II) in dimethyl sulfoxide have been recorded and analyzed. The cations are four-coordinated. Pt-O in Pt(H2O)4(2+) is 2.01(1) angstrom and Pt-N in Pt(CH3CN)4(2+) is 2.00(1) angstrom. The dimethyl sulfoxide solvated cations of both platinum and palladium cont

cis-Influence and trans-Influence on Bond Distances. Synthesis and Crystal Structures of the Bis(trifluoromethanesulfonates) of Tetrakis(dimethylsulfide)- and Tetrakis(1,4-thioxane)-platinum(II)

Crystals of [Pt{(CH3)2S}4](CF3SO3)2, M(r) = 741.76, and [Pt(C4H8OS)4](CF3SO3)2.H2O, M(r) = 927.93, were prepared by dissolution of platinum(II) hydroxide in solutions of trifluoromethanesulfonic acid in dimethyl sulfide and 1,4-thioxane, respectively. The structures were determined from X-ray intensity data (Mo K-alpha, lambda = 0.7107 angstrom) collected at room temperature with a CAD-4 diffracto

Proton NMR Kinetic Study of Ligand Exchange on Bis(1,4-dithiane)platinum(II), Bis(1,4-dithiane)palladium(II) and Tetrakis(dimethylsulfide)platinum(II) : High Presssure NMR Kinetics 51

Ligand exchange on square-planar Pt(1,4-dithiane)2(2+), Pd(1,4-dithiane)2(2+), and Pt(Me2S)4(2+) has been studied as a function of temperature and pressure by H-1 NMR line-broadening, isotopic labeling, and magnetization transfer experiments with deuteriated nitromethane as solvent. Second-order rate constants and activation parameters are as follows: for 1,4-dithiane exchange on Pt(1,4-dithiane)2Ligand exchange on square-planar Pt(1,4-dithiane)2(2+), Pd(1,4-dithiane)2(2+), and Pt(Me2S)4(2+) has been studied as a function of temperature and pressure by H-1 NMR line-broadening, isotopic labeling, and magnetization transfer experiments with deuteriated nitromethane as solvent. Second-order rate constants and activation parameters are as follows: for 1,4-dithiane exchange on Pt(1,4-dithiane)2

Guanine-O6 Methylation Reduces the Reactivity of D(GpG) towards Platinum Complexes

06-methylated guanine dinucleotides were used to study the influence of hydrogen bonding on the specific binding of the antitumor drug cDDP, cis-PtCl2(NH3)2, to DNA. In this interaction, the guanine-06 site appears to be important in explaining the preference for a pGpG-N7(1),N7(2) chelate, which results from H-bridge formation with the ammine ligand of cDDP. Guanine-06 methylated dinucleotides an06-methylated guanine dinucleotides were used to study the influence of hydrogen bonding on the specific binding of the antitumor drug cDDP, cis-PtCl2(NH3)2, to DNA. In this interaction, the guanine-06 site appears to be important in explaining the preference for a pGpG-N7(1),N7(2) chelate, which results from H-bridge formation with the ammine ligand of cDDP.Guanine-06 methylated dinucleotides and

trans influence on bond distances. Structures of trans-diiodobis(tetrahydrothiophene)palladium(II) and trans-diiodobis(tetrahydrothiophene)platinum(II)

Crystals of trans-diiodobis(tetrahydrothiophene)-palladium(II) and trans-diiodobis(tetrahydrothiophene)platinum(II) were prepared by dissolving the appropriate metal iodide in tetrahydrothiophene at 353 K and cooling to room temperature. Crystal data at room temperature (Mo K-alpha, lambda = 0.7107-angstrom) are: [PdI2(C4H8S)2], M(r) = 536.54, triclinic, P1BAR, a = 8.4920 (8), b = 8.8248 (1), c =

Solvent Exchange and Complex Formation Reactions of Pd(II) in Aqueous Solution. Mechanistic Information from High Pressure Studies

High pressure NMR and stopped-flow techniques have been employed to study a series of water exchange and complex formation reactions of Pd(II) outlined in (1) and (2). The volumes of activation show an interesting correlation with the partial molar volume of the entering ligand and underline the operation of an associative substitution mechanism in all cases.High pressure NMR and stopped-flow techniques have been employed to study a series of water exchange and complex formation reactions of Pd(II) outlined in (1) and (2). The volumes of activation show an interesting correlation with the partial molar volume of the entering ligand and underline the operation of an associative substitution mechanism in all cases.

Rank Reduction with Convex Constraints

This thesis addresses problems which require low-rank solutions under convex constraints. In particular, the focus lies on model reduction of positive systems, as well as finite dimensional optimization problems that are convex, apart from a low-rank constraint. Traditional model reduction techniques try to minimize the error between the original and the reduced system. Typically, the resulting re

Polarity dependent strongly inhomogeneous In-incorporation in GaN nanocolumns

In this work, GaN/InGaN/GaN nanocolumns (NCs) have been grown by molecular beam epitaxy. Selective area growth (SAG) and self-organized growth (SOG) were performed simultaneously in patterned and unpatterned regions of the same substrate, respectively. The resulting structures show different tip morphologies and structural properties due to the different polarity along the growth direction, namely