Reduction Of Indium Research Articles

Bimetallic neutral and anionic complexes of transition metal (Co, Mn) carbonyls with indium(III) phthalocyanine.

Heterobimetallic {[Co(CO)4]-[InIII(Pc2-)]} (1) and (Cp*2Cr+){[Mn(CO)5]-[InIII(Pc˙3-)]}·2C6H4Cl2 (2) complexes based on indium(III) phthalocyanine (Pc) were obtained as crystals. The complexes were synthesized by single (1) and double (2) reduction of indium(III) phthalocyanine chloride in the presence of transition metal carbonyls. Complex 1 contains dianionic Pc2- macrocycles. Thus, the coordinated Co(CO)4 carbonyl accepts an electron in the one-electron reduction forming a diamagnetic [Co(CO)4]- anion. Complex 2 contains a heterobimetallic {[Mn(CO)5]-[InIII(Pc˙3-)]}- anion and paramagnetic Cp*2Cr+ counter cations. Therefore, in the double reduction, electrons are transferred to Mn(CO)5 forming a diamagnetic [Mn(CO)5]- anion and to the Pc2- macrocycle forming a paramagnetic radical Pc˙3- trianion. Such assignments for 1 and 2 are in line with optical spectra, crystal structures and the data of magnetic measurements. The spectrum of 1 in the UV-visible range is similar to that of the starting InIIIClPc. The formation of 2 is accompanied by an essential blue-shift of the Q-band of Pc as well as by the appearance of an intense NIR band at 1005 nm characteristic of Pc˙3-. Compound 1 is EPR silent and diamagnetic, whereas the value of the effective magnetic moment of 2 is 4.24μB at 300 K, which corresponds to the contribution of S = 1/2 (Pc˙3-) and S = 3/2 (Cp*2Cr+) spins. Both weakly coupled paramagnetic centers (J = -0.41 cm-1) are observed in the EPR spectra.

Synthesis and reactivity of indium(I) 1-carba-closo-undecachlorododecaborate.

The arene-solvated indium(I) species [In(C7H8)3][CHB11Cl11] (1) and [In(C6H5Br)1.5][CHB11Cl11] (2) were obtained by a redox reaction involving the silver salt Ag[CHB11Cl11] and indium powder at 80 °C in a toluene or bromobenzene solution. These thermally stable compounds react with triphenylphosphine and the N-heterocyclic carbene 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene under reduction of indium(I) to indium metal and oxidation of the ligands to phosphonium and imidazolium cations contrary to the more commonly observed disproportionation reactions. The presence of 2 equiv of carbene led to deprotonation of the anion to give the dianion [CB11Cl11](2-). Interactions of In(+) with soft donor ligands such as phosphines, olefins, alkynes, and aromatics are weak, and a crystalline solid was only obtained with the nonvolatile phosphinoacetylene Mes2PC≡CPh (Mes = 2,4,6-Me3C6H2). The structure of this compound displays In···C interactions involving the triple bond and the π system of one mesityl group but no In···P contact. Solutions of 2 in fluorobenzene also showed moderate activity as the catalyst for intramolecular hydroamination of primary and secondary aminopentenes. The new compounds were characterized by multinuclear NMR spectroscopy and X-ray diffraction for compounds 1, 2, and 4-6.

Indium–silver alloy nanocrystals glass with fluorescence: A model in borosilicate glasses

We demonstrated a model to realize the growth of indium–silver alloy nanocrystals in borosilicate glass by sol–gel method plus a controlled atmosphere. The presence of spherical indium–silver alloy nanoparticles with 5 nm average grain size and good dispersed form in borosilicate glass was confirmed by transmission electron microscopy imaging. Reduction of indium–silver ions to indium–silver alloy neutral nanocrystals was revealed through X-ray powder diffraction and X-ray photoelectron spectra (XPS). Remarkably, indium–silver alloy nanocrystals borosilicate glass exhibited fluorescence at around 423 nm which nominated it as the candidate glass for laser sources, nonlinear media and photonic applications.

Reduction of indium(III) at dropping mercury electrode in the presence of pyridine in aqueous and ethanol–water media

The reduction of indium(III) at dropping mercury electrode in aqueous as well as in 25% ethanol–water media in the presence of pyridine has been studied at a constant ionic strength (0.1 M KNO3) and at 30 and 40 °C. The reduction is diffusion-controlled but the electrode process is quasi-reversible in both media. The reversible half-wave potential values,E1/2r, have been obtained by Gelling’s method. The plot ofE1/2r versus pyridine concentration is a straight line and the number of ligands,j, was determined from the slope. This shows the formation of a single complex. The stability constant has been determined by Lingane’s method. In(III) forms one complex species with composition 1:1, [In(py)]3+. The values of thermodynamic parameters ΔG, ΔHand ΔSof the complexation reaction have also been determined at 30 °C.

Stimulatory Current at the Edge of an Inactive Conductor in an Electric Field: Role of Nonlinear Interfacial Current–Voltage Relationship

Cardiac electric field stimulation is critical for the mechanism of defibrillation. The presence of certain inactive epicardial conductors in the field during defibrillation can decrease the defibrillation threshold. We hypothesized this decrease is due to stimulatory effects of current across the interface between the inactive conductor and the heart during field stimulation. To examine this current and its possible stimulatory effects, we imaged transmittance of indium-tin-oxide (ITO) conductors, tested for indium with X-ray diffraction, created a computer model containing realistic ITO interfacial properties, and optically mapped excitation of rabbit heart during electric field stimulation in the presence of an ITO conductor. Reduction of indium decreased transmittance at the edge facing the anodal shock electrode when trans-interfacial voltage exceeded standard reduction potential. The interfacial current-voltage relationship was nonlinear, producing larger conductances at higher currents. This nonlinearity concentrated the interfacial current near edges in images and in a computer model. The edge current was stimulatory, producing early postshock excitation of rabbit ventricles. Thus, darkening of ITO indicates interfacial current by indium reduction. Interfacial nonlinearity concentrates current near the edge where it can excite the heart. Stimulatory current at edges may account for the reported decrease in defibrillation threshold by inactive conductors.

Voltammetric Reduction of In(III)-Eriochrome Red B Complexes

The reduction of indium(III)-Eriochrome Red B complex is studied in wide ranges of pH and concentrations by cyclic voltammetry with a linear potential sweep. The ratio of components in the complex is found to be 1 : 2. The mechanism of the electrode process is discussed. It is shown that In(III) can be determined in the presence of Cd(II) and Fe(III).

Current oscillations of indium(III) at a dropping mercury electrode

Abstract Oscillations in currents observed at potentials around the polarographic maximum during the reduction of indium(III) in potassium nitrate solutions have been characterized. Effects of surfactants, supporting electrolyte concentration, mercury drop rate, resistors in series, and temperature are reported. The current–time series data of the oscillations obtained by holding the potential fixed are used to generate a one-dimensional return map. The minima of adjacent peaks of the oscillations are used for the return map. Analysis of the return map reveals the noise, repeatability of the oscillations, and enhances differences observed in the oscillations between potential settings.

Current oscillations in the reduction of indium(III) and gallium(III) in dilute chloride and nitrate solutions at the dropping mercury electrode

Electrochemical oscillations have been observed during the reduction of indium(III) and gallium(III) in 0.02 M chloride and nitrate solutions at a dropping mercury electrode. No external resistance attached in series with the cell was required. The results show that Triton X-100, a common surface active agent, has some influence on the oscillations but was not a prerequisite for the oscillations in the reduction of indium(III).

Mixed-mode oscillations and incomplete homoclinic scenarios to a saddle focus in the indium/thiocyanate electrochemical oscillator

The complex mixed-mode and chaotic oscillations in the reduction of indium(III) at a hanging mercury drop electrode in thiocyanate solution are studied in experimental detail in the parameter plane. With the aid of a simple model developed previously, we critically discuss the relation of the experimentally observed periodic–chaotic sequences with those predicted by the Shil’nikov theory of homoclinic orbits. It appears helpful to distinguish between two fundamentally different types of mixed-mode behavior: ‘‘type 1’’ related to the incomplete homoclinic scenarios observed in the present system and its model; ‘‘type 2’’ related more directly to the Shil’nikov behavior and the classical Rössler type of reinjection mechanism. The definitions and properties of both types of mixed-mode oscillation are worked out in some detail.

Mixed-mode and chaotic oscillations in a simple model of an electrochemical oscillator

We present some preliminary results obtained with a simple three-variable model that should adequately describe the mixed-mode and chaotic oscillations observed during the reduction of indium(III) at mercury in the presence of thiocyanate. This model is the first to satisfactorily reproduce such complex dynamic behavior in an electrochemical system

A criticism of kondziela and biernat's discussion of bond's data for reduction of indium in halide media

A criticism of kondziela and biernat's discussion of bond's data for reduction of indium in halide media

A criticism of Kondziela and Biernat's discussion of bond's data for reduction of indium in halide media

A criticism of Kondziela and Biernat's discussion of bond's data for reduction of indium in halide media

Polarography of indium in thioglycollic and ascorbic acid media

The polarographic reduction of indium in thioglycollic acid is reversible whereas in ascorbic acid it is quasireversible. The formal potentials have been determined by amalgam polarography and the stability constants calculated.

Polarography of indium in glycollate medium

Reversible reduction of indium in glycollic acid has been followed by de polarography and the stability constants of the indium glycollate complexes calculated by the method of DeFord and Hume.

Polarographic studies on the formation constants of complexes of indium with aspirin

A polarographic study of indium–aspirin complexes has been carried out, with the ionic strength kept constant (µ= 1) by adding requisite amounts of sodium perchlorate. The reduction of indium in various concentrations (0–0·36M) is diffusion-controlled but the process is not reversible. The kinetic parameters α and Ks have been calculated by Gelling's method. The value of Ks was about 2 ± 0·5 × 10–3 cm./sec., showing that the reduction is a quasi-reversible process. Since the reduction is quasi-reversible, Gelling's method is used to determine the reversible half-wave potential (E1/2r). Thus, knowing E1/2r, the stability constants of the various complexes in the indium–aspirin anion system have been evaluated by DeFord and Hume's treatment. The values for various complex species present in the solution at 30°, In(Asp)2+, In(Asp)2+, In(Asp)3, In(Asp)4–, and In(Aps)52–, are 3 × 104, 5 × 104, 300 × 104, 650 × 104, and 13,500 × 104, respectively. Since the reduction is diffusion-controlled, indium can be determined polarographically in acetylsalicylate solution.

Reduction of indium after oxidation in fuming perchloric acid

Evidence is given in support of the theory that high results obtained for reduction titrations of iridium solutions which have been fumed with perchloric acid are due to retention in solution of volatile reduction products of the acid.

Reduction of indium at the dropping mercury electrode in lithium chloride medium

The reduction of indium at the dropping mercury electrode in lithium chloride solution has been studied. The reduction is diffusion-controlled but the process is not reversible. The kinetic parameters have been calculated by Matsuda's treatment for quasi-reversible reductions. The ks was found to be of the order of 10−4 cm/s, showing that the reduction is quasi-reversible. The effect of temperature and concentration of lithium chloride on the kinetic parameters have been investigated. As the temperature or concentration of lithium chloride increases, the reduction becomes more reversible.

Reduction of indium at the dropping mercury electrode in non-complexing media

The reduction of indium at the dropping mercury electrode in sodium nitrate and sodium perchlorate solutions has been studied. The induction is diffusion controlled but the process is not reversible. The kinetic parameters α and k s, have been calculated by Gelling's method. The k s was found to be of the order of 1·25 × 10 −3 cm/s, showing that the reduction is a quasi-reversible process. The effect of temperature and concentration of the supporting electrolyte on kinetic parameters have been investigated. The apparent heat of activation Δ H s has been calculated. As the temperature increases or the concentration of the supporting electrolyte decreases, the reduction proceeds towards more reversible side.