Copper Catalysis of the Oxidation of Iodide by [FeIII(bpy)2(CN)2]+ in Acetonitrile

Wang, Xiaoguang; Stanbury, David M.

doi:10.1021/jp046782q

Cited by 13 publications

(23 citation statements)

References 11 publications

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“…The oxidation of the iodide ion and its mechanism under different experimental conditions has been of interest for years due to its applications especially in energy production and solar cells. [1][2][3][4][5][6][7][8][9] A number of studies explored the mechanism of the oxidation of the iodide ion by various transition metal complexes that can be used to enhance the efficiency of the dye-sensitized solar cells (DSSCs). The applications of transition metal complexes based upon ruthenium, cobalt, copper, nickel, and iron metals have been surfaced as sensitizers in DSSCs.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of the oxidation of iodide by dicyanobis(phenanthroline)iron(III) in a binary solvent system

Khattak

Khan

Summer

et al. 2020

Int J of Chemical Kinetics

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Oxidation of the iodide ion is an important facet of the solar cells such as perovskite solar cells and dye-sensitized solar cells. The rate of reaction undoubtedly depends upon several factors. Such parameters include reaction media, electrolyte, and the nature of solvents, and electrolyte. If these factors are optimized then the rate of the reaction can be controlled and could be used to get the maximum benefit out of it such as economically and industrially cost-effective uses of the reaction and globally environmentally benign. We studied the kinetics of the oxidation of the iodide ion in the binary solvent system that consisted of 10% (v/v) tertiary butyl alcohol and water. The transition metal complex such as dicyanobis(phenanthroline)iron(III) oxidizes the iodide ion spontaneously without any external triggering with a fast rate at 293 ± 1 K. The reaction was probed under the pseudo-first-order condition with an excess concentration of the iodide ion over dicyanobis(phenanthroline)iron(III) at 0.06 M ionic strength. The reaction was observed independent of the concentration of dicyanobis(phenanthroline)iron(III), that is, the zero order and third order with respect to the iodide ion in the selected solvent system. An overall third-order was observed for the redox reaction. The value of the multiplication product of the molar absorptivity (ɛ), path length of the cuvette (b), and overall rate constant (k) was deduced to be 1.59 × 10 6 M −3 s −1. The observed zero-order rate constant of the reaction was increased by the fractional (1.5) power of the concentration of protons in the excess concentration of acid 1 mM to 0.1 M. The multiplication product of ɛ⋅b to the fractional order rate constant (k′) was found 0.773 M −1.5 s −1 that confirms protonation of triiodide in acidic-10% (v/v) tertiary butyl alcohol-water. The effect of ionic strength showed a similar impact in different compositions of solvents such as 5, 10, and 20% (v/v) tertiary butyl alcoholwater. The observed zero-order rate constant was decreased upon increasing the ionic strength in each medium consisting of the binary solvent system.

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Section: Introductionmentioning

confidence: 99%

Kinetics of the oxidation of iodide by dicyanobis(phenanthroline)iron(III) in a binary solvent system

Khattak

Khan

Summer

et al. 2020

Int J of Chemical Kinetics

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“…At this stage the electron is transferred to ferricyanide giving rise to reduced ferrocyanide along with production of HI 2 AE ion, which in the slow step gives rise to I 2 )AE . Production of I 2 )AE ion in aqueous [22,23] and in acetonitrile medium [24,25] has already been reported. Alternatively [26,27] hydrogen ion with iodide ion may give rise to HI 2 ) in the first step, which may react with Fe III giving rise to reduced Fe II and HI 2 AE .…”

Section: Mechanism Without Added Ruthenium(iii) (Single Catalyzed Reamentioning

confidence: 87%

“…However, due to the instability of this oxidant in solution, related oxidants like [Fe III (bpy) 2 (CN)] + have been shown to be highly effective as sensitizers in photochemical cells of the Gra¨tzel type [21][22][23]. Recently oxidation of iodide ions by various iron(III) complexes in acetonitrile has been reported and it has been shown that trace levels of copper ions are the potent catalysts for the reaction [24,25]. We have already reported first order kinetics with respect to [Fe(CN) 6 ] 3) and [H + ] ions and second order w.r.t.…”

Section: Introductionmentioning

confidence: 99%

Ruthenium(III) catalysis in the reaction of hexacyanoferrate(III) and iodide ions in perchloric acid medium

Tandon

Mehrotra

Srivastava

et al. 2007

Transition Met Chem

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RuCl 3 can further catalyze the reaction between hexacyanoferrate(III) and iodide ions, which is already catalyzed by the hydrogen ions obtained from perchloric acid. Rate, when the reaction is catalyzed only by the hydrogen ions, was separated graphically from the rate when ruthenium(III) and H + ions both catalyze the reaction. Reactions studied separately in the presence as well as in the absence of RuCl 3 under similar conditions were found to follow second order kinetics w.r.t. [I ) ]. While the rate showed direct proportionality w.r.t. [Fe(CN) 6 ] 3) and [RuCl 3 ]. At low concentrations the reaction shows direct proportionality with respect to [H + ] which tends to become proportional to the square of hydrogen ion concentrations. External addition of [Fe(CN) 6 ] 4) ions retards the reaction velocity while change in ionic strength of the medium has no effect on the rate. With the help of the intercept of the catalyst graph, extent of the reaction, which takes place without adding ruthenium(III) was calculated and it was in accordance with the values obtained from the separately studied reaction in which only H + ions catalyze the reaction. It is proposed that ruthenium forms a complex, which slowly disproportionates into the rate-determining step. Arrhenius parameters at four different temperatures were also calculated.

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“…At this stage an electron is transferred to hexacyanoferrate(III) giving rise to reduced hexacyanoferrate(II) along with production of HI 2 AE ion, which in the slow step gives rise to I 2 ) AE . Production of I 2 ) AE ion in aqueous [19,25,26] and in acetonitrile medium [28,29] has already been reported. Alternatively [30,31] hydrogen ion in the pre-equilibrium step with iodide ion may give rise to HI 2 ) , which may react with Fe III giving rise to reduced Fe II and HI 2 AE .…”

Section: Mechanism Without Added Iridium(iii) (Single Catalysed Reactmentioning

confidence: 88%

“…However, due to the instability of this oxidant in solution, related oxidants like [Fe III (bpy) 2 (CN) 2 ] + have been shown to be highly effective as sensitizers in photochemical cells of the Gra¨tzel type [24][25][26]. Oxidation of iodide ion by (loxo) diiron (III, III) complexes in weakly acidic medium [27] and by various iron(III) complexes in acetonitrile has been reported and it has been shown that trace levels of copper ions are the potent catalysts for the reaction [28,29]. Oxidation of iodide ions by hexacyanoferrate(III) has already been reported by us in which first order kinetics with respect to [K 3 Fe(CN) 6 ] and [H + ] ions and second order with respect to [I ) ] was observed, when the reaction is catalyzed by palladium(II) in hydrochloric acid [30] and ruthenium(III) in sulphuric acid medium [31].…”

Section: Introductionmentioning

confidence: 99%

Iridium(III) catalyzed oxidation of iodide ions in aqueous acidic medium

Tandon

Mehrotra

Srivastava

et al. 2007

Transition Met Chem

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Oxidation of iodide ions by K 3 Fe(CN) 6 , catalyzed by hydrogen ions obtained from hydrochloric acid was found to be further catalyzed by iridium(III) chloride. Rate, when the reaction is catalyzed only by the hydrogen ions, was separated from the rate when iridium(III) and H + ions both, catalyze the reaction. Reactions studied separately in the presence as well as in the absence of IrCl 3 under similar conditions were found to follow second order kinetics with respect to [I ) ]. While the rate showed direct proportionality with respect to [K 3 Fe(CN) 6 ] and [IrCl 3 ]. At low concentrations the reaction shows direct proportionality with respect to [H + ] which tends to become proportional to the square of hydrogen ions at higher concentrations. Strong retarding affect of externally added hexacyanoferrate(II) ions was observed in the beginning but further addition affects the rate to a little extent. Changes in [Cl ) ] and also ionic strength of the medium have no effect on the rate. With the help of the intercept of catalyst graph, the extent of the reaction, which takes place without adding iridium(III), was calculated and was found to be in accordance with the values obtained from the separately studied reactions in which only H + ions catalyze the reaction. It is proposed that iridium forms a complex, which slowly disproportionates into the rate-determining step. Thermodynamic parameters at four different temperatures were calculated.

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Copper Catalysis of the Oxidation of Iodide by [Fe^III(bpy)₂(CN)₂]⁺ in Acetonitrile

Cited by 13 publications

References 11 publications

Kinetics of the oxidation of iodide by dicyanobis(phenanthroline)iron(III) in a binary solvent system

Kinetics of the oxidation of iodide by dicyanobis(phenanthroline)iron(III) in a binary solvent system

Ruthenium(III) catalysis in the reaction of hexacyanoferrate(III) and iodide ions in perchloric acid medium

Iridium(III) catalyzed oxidation of iodide ions in aqueous acidic medium

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