Osmium(VIII) oxidation of arsenic(III) in aqueous sulphuric acid

The oxidation of As^III by Os^VIII or Os^VI in aqueous H₂SO₄ follows the rate law:

Oxidation of chromium(III) by alkaline hexacyanoferrate(III)

Alkaline hexacyanoferrate(III) oxidation of freshly prepared solutions of Cr^III (pH>12) at 27°C follows the rate law, Equation 1:

Solvent effects on the anation ofcis-diaquo-bis-ethylenediamine cobalt(III) by L-proline

The anation kinetics of the title complex were investigated spectrophotometrically in aqueous methanol, ethanol, ipropanol, t-butanol and dioxane, and the following rate law was established:

Formation of Tc(III)-EDTA complex

Tc(III)-EDTA complex has been synthesized by the ligand substitution reaction of hexakis-(thiourea) technetium(III) ion with EDTA. The complex exhibits absorption maxima at 368 and 470 nm. The formation reaction proceeds predominantly as follows:

Kinetic studies of the oxidation ofN-(2-hydroxycyclohexyl)-ethylenediaminetriacetatochromate(III) by periodate

The kinetics of the oxidation of [Cr^III(H₂O)(XOH)], (XOH=N-(2-hydroxycyclohexyl)ethylenediaminetriacetate) to Cr^VI by periodate have been investigated in aqueous solution at various pH values (6.00–7.20) and temperatures (15.0–35.0°C). The reaction follows the rate law:

Effect of ionic strength and ionic interactions on the oxidation of Fe(II)

The rates of oxidation of Fe(II) in NaCl and NaClO ₄ solutions were studied as a function of pH (6 to 9), temperature (5 to 25°C), and ionic strength (0 to 6m). The rates are second order with respect to [H⁺] or [OH^–] and independent of ionic strength and temperature. The overall rate of the oxidation is given by

Thermokinetic Studies of the Process for Electrorefining Silver

In this work some calorimetric measurements were also carried out on the electrorefining silver by using different current densities with a Calvet type microcalorimeter at room temperature. The ratio (R) of the measured heat (

Kinetics of substitution of aquo ligands fromcis-diaquo-bis-(biguanide) cobalt(III) and chromium(III) ions by aspartic acid in ethanol—water mixtures

The kinetics of substitution of aqua ligands fromcis-diaqua-bis(biguanide)cobalt(III) and chromium(III) ions by aspartic acid in EtOH–H₂O media have been studied spectrophotometrically in the 30 to 45°C range. We propose the following rate law for the anation

Kinetics and mechanism of oxidation of chromium(III)-tetraoxalylurea complex by periodate

A novel chromium(III) complex of tetraoxalylurea was prepared. In aqueous solutions, [Cr^III(H₂L)(H₂O)]⁺ (H₂L = diprotonated tetraoxalylurea) is oxidized by IO ₄ ^– according to the rate law

Substitution of aqua ligands fromcis-diaqua-bis(bipyridyl) ruthenium(II) by 1, 10-phenanthroline in aqueous medium

The kinetics of aqua ligand substitution fromcis-[Ru(bipy)₂(H₂O)₂]²⁺ by 1, 10-phenanthroline (phen) have been studied spectrophotometrically in the 35 to 50°C temperature range. We propose the following rate law for the reaction within the 3.65 to 5.5 pH range:

Ionic Mobility, Structure, Phase Transition, and Conductivity in (NH4)3Sb4F15

Fluoride and ammonium ion dynamics in (NH₄)₃Sb₄F₁₅ was studied by ¹H and ¹⁹F NMR spectroscopy in the range 180-440 K. Types of ionic motion were determined, and their activation energies were estimated. The crystal structure of a single crystal of (NH₄)₃Sb₄F₁₅ (space group ) was solved. In the range K, a reversible phase transition has been found. Based on the experimental values of conductivity of (NH₄)₃Sb₄F₁₅ ( S/cm at T = 440 K), this antimony(III) fluoride is classified as a superionic conductor.     

Methionine anation of aquachromium(III)

The kinetics of anation of chromium(III) species, [Cr(H₂O)₆]³⁺ and [Cr(H₂O)₅OH]²⁺, by DL-methionine have been studied spectrophotometrically. Effects of varying [methionine]_T, [H⁺], and temperature were investigated. The results are in accord with a mechanism involving a fast 11 outer-sphere association between chromium(III) species and amino acid zwitterion, followed by transformation of the outer-into inner-sphere complex by slow interchange. The rate law consistent with the mechanism is as follows:

Kinetics of the manganese(III)-oxalate reaction in acidic sulphate media

The kinetics of the reaction of manganese(III) with oxalic acid (OA) has been studied in H₂SO₄ solutions. Under the experimental conditions of 6 × 10^–3 <>₀ < 0.4=" mol=">^–3 and [H₂SO₄]₀ 0.2 mol dm^–3 the observed pseudo-first order rate constant k _obs follows the expression

Kinetics and mechanism of anation of hexaaquochromium(III) by 2-aminopyridine

The kinetics of substitution of aqua ligands from the hexaaquochromium(III) ion by 2-aminopyridine (2-ampyH⁺) in aqueous medium has been studied spectrophotometrically in the 40–55° C range. The rate law involving the outer sphere complex formation has been established at pH 2.7 as

Kinetic study of hydrogen peroxide reaction with hydroxonitrilotri(methylenephosphonato)iron(III) complex

The decomposition of hydrogen peroxide in the presence of hydroxonitrilotri(methylenephosphonato)iron(III), [Fe(NTMP)(OH)^4–], was studied in nitrate media (=0.10–0.26 M) over the 0.2–0.5 mM concentration range for the iron complex and the temperature range 26–40°C. The rate law;

Kinetics of the oxidation of [N-(2-hydroxyethyl)-ethylene-diamine-N,N′,N′-triacetato]cobalt(II) by N-bromosuccinimide

The kinetics of the oxidation of [N-(2-hydroxyethyl)-ethylene-diamine-N,N,N-triacetato] cobalt(II), [Co^II-(HEDTA)]^–, by N-bromosuccinimide, NBS, have been studied in aqueous solutions and water-methanol solvent mixtures under various conditions. The reaction stoichiometry indicates that one mole of NBS reacts with one mole of [Co^II(HEDTA)]^–. In aqueous solutions the reaction obeys the following rate law:

Dissociation Constants of Protonated Cysteine Species in NaCl Media

The sulfur-containing biomolecule, cysteine has a role in physiological and natural environment because of its strong interactions with metals. To understand these interactions of metals with cysteine, one needs reliable dissociation constants for the protonated cysteine species [ CH(CH₂SH)COOH; H₃B⁺]. The values of dissociated constants, p , for protonated cysteine species (H₃B⁺ H⁺ + H₂B, K ₁; H₂B H⁺ + HB^–,K ₂; HB^– H⁺ + B^2–,K ₃) were determined from potentiometric measurements in NaCl solutions as a function of ionic strength, 0.5–6.0 mol-(kgH₂O)^–1 and between 5, and 45°C. The equations

Antimony(III) Chloride Complexes with Benzylpyridines: Synthesis and Luminescence. Crystal Structure of Bis(2-benzylpyridinium) Pentachloroantimonate(III)

The antimony(III) chloride complexes with 2- and 4-benzylpyridine were synthesized and studied using elemental analysis, X-ray diffraction analysis, IR spectroscopy, and luminescence spectroscopy. The crystal structure of bis(2-benzylpyridinium) pentachloroantimonate(III) was determined. The crystals are triclinic: a = 9.628(1) Å, b = 15.284(2) Å, c = 19.174(2) Å, = 99.962(2)°, = 101.233(2)°, = 99. 216(2)°; Z = 4, (calcd) = 1.591 g/cm³, space group P , R = 0.0358. The structure consists of polymeric chains of [Sb₂Cl₁₀]^4n– _n anions and [C₁₂H₁₁NH]⁺ cations combined into a framework by the N–H···Cl hydrogen bonds. The electronic and geometrical factors responsible for a relatively low intensity of the luminescence emitted by the complexes of antimony(III) chloride with 2- and 4-benzylpyridine at 77 K are discussed.     

Trace metal ion catalysis; kinetics and mechanism of oxidation of metol by hydrogen peroxide in the presence of iron(III) sulphate in acid perchlorate

The kinetics of oxidation of N-methyl-p-aminophenol (metol) by H₂O₂ in the presence of trace levels of Fe^III have been studied in an HClO₄ medium. The reaction mechanism is complex and the catalytic role of Fe^III in the sulphato form is indicated. The following rate law accounts for the experimental observations:

O-H ... O(S) hydrogen bonds in 2-hydroxy(thio)benzamides. Survey of spectroscopic and structural data

Summary From a survey of spectroscopic and structural data of six corresponding 2-hydroxybenzamides and 2-hydroxythiobenzamides (amide, N-methylamide, N,N-dimethylamide, piperidide, morpholide, 2,6-dimethylpiperidide) remarkable similarities between O(N)-H ... O and O(N)-H ... S hydrogen-bonds are obtained, concerning both, hydrogen-bond patterns and hydrogen-bond strengths. In dilute solution the OH groups of all compounds are intramolecularly associated to the (thio)carbonyl O (S) atoms with distinctly larger hydrogen-bond strengths for primary and secondary amides [ (O-H)=2950–3020 cm^–1, (OH)=12.16–11.99 ppm] and thioamides [ (O-H)=2960–3000 cm^–1, (OH)=11.65–11.13 ppm], than for tertiary amides [ (O-H)=3200–3250 cm^–1, (OH)=9.95–8.95 ppm] and thioamides [ (O-H)=3245–3330 cm^–1, (OH)=8.09–7.06 ppm]. In the solid state, the OH groups of the primary and secondary (thio)amides are also engaged in rather strong intramolecular O-H ... O=C [O ... O=2.51 Å, (O-H)=2700–2750 cm^–1] and O-H ... S=C [O ... S=2.90–2.94 Å, (O-H)=2700–2840 cm^–1] hydrogen-bonds; thetrans-NH groups of the primary (thio)amides and the NH groups of the secondary (thio)amides connect the molecules to N-H ... O-H [N ... O=2.93–3.10 Å, (N-H)=3319–3407 cm^–1] hydrogen-bonded chains; the remainingcis-NH groups of the primary (thio)amides give rise to eight-membered cyclic dimers via N-H ... O=C [N ... O=2.93 Å, (N-H)=3226 cm^–1] and N-H ... S=C [N ... S=3.46–3.47 Å, (N-H)=3233–3277 cm^–1] hydrogen-bonds. Contrary, the OH groups of the tertiary (thio)amides are intermolecular associated in the solid state and link the molecules to O-H ... O=C [O ... O=2.63–2.75 Å, (O-H)=3075–3135 cm^–1] and O-H ... S=C [O ... S=3.18–3.26 Å, (O-H)=3130–3190 cm^–1] hydrogen-bonded chains.

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O-H ... O(S)-Wasserstoffbrückenbindungen in 2-Hydroxy(thio)benzamiden. Ein Überblick über spektroskopische und strukturelle Daten

Zusammenfassung Aus einer Zusammenstellung von spektroskopischen und strukturellen Daten von sechs entsprechenden 2-Hydroxybenzamiden und 2-Hydroxythiobenzamiden (Amid, N-Methylamid, N,N-Dimethylamid, Piperidid, Morpholid, 2,6-Dimethylpiperidid) ergeben sich bemerkenswerte Analogien zwischen O(N)-H ... O und O(N)-H ... S H-Brücken, die sowohl die H-Brücken-Muster als auch die H-Brücken-Stärken betreffen. In verdünnter Lösung sind die OH-Gruppen aller Verbindungen intramolekular mit den O(S)-Atomen der (Thio)Carbonylgruppen assoziiert, wobei die H-Brücken bei den primären und sekundären Amiden [ (O-H)=2950–3020 cm^–1, (OH)=12.16–11.99 ppm] und Thioamiden [ (O-H)=2960–3060 cm^–1, (OH)=11.65–11.13 ppm] deutlich stärker sind, als bei den tertiären Amiden [ (O-H)=3200–3250 cm^–1, (OH)=9.95–8.95 ppm] und Thioamiden [ (O-H)=3245–3330 cm^–1, (OH)=8.09–7.06 ppm]. Im Festkörper weisen die primären und sekundären (Thio)Amide ebenfalls sehr starke intramolekulare O-H ... O=C [O ... O=2.51 Å, (O-H)=2700–2750 cm^–1] und O-H ... S=C [O ... S=2.90–2.94 Å, (O-H)=2700–2840 cm^–1] H-Brücken auf; dietrans-NH-Gruppen der primären (Thio)Amide und die NH-Gruppen der sekundären (Thio)Amide verknüpfen die Moleküle über N-H ... O-H H-Brücken [N ... O=2.93–3.10 Å, (N-H)=3318–3407 cm^–1] zu Ketten; die verbleibendencis-NH-Gruppen der primären (Thio)Amide bilden zyklische, über N-H ... O=C [N ... O=2.93 Å, (N-H)=3226 cm^–1] und N-H ... S=C [N ... S=3.46–3.47 Å, (N-H)=3233–3277 cm^–1] H-Brücken gebundene, 8-Ring-Dimere. Im Gegensatz dazu sind die OH-Gruppen der tertiären (Thio)Amide im Festkörper intermolekular assoziiert und verknüpfen die Moleküle über O-H ... O=C [O ... O=2.63–2.75 Å, (O-H)=3075–3135 cm^–1] und O-H ... S=C [O ... S=3.18–3.26 Å, (O-H)=3130–3190 cm^–1] H-Brücken zu Ketten.