Electron-Transfer Reactions in Non-Aqueous Media. VI. A Temperature-Dependence Study of the Reduction of cis-[CoCl2(en)2]+ by Iron(II) in Me2SO

1979 ◽  
Vol 32 (10) ◽  
pp. 2275 ◽  
Author(s):  
L Spiccia ◽  
DW Watts
Keyword(s):  
Electron Transfer ◽  
Temperature Dependence ◽  
Transfer Process ◽  
Iron Atom ◽  
Aqueous Media ◽  
Transfer Reactions ◽  
Electron Transfer Process ◽  
First Order ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of the reduction of cis-[CoCl2(en)2] � (en = ethylenediamine) by iron(II) in Me2SO have been studied at four temperatures. The rate law has the form d[CoIII]/dt = kK [COIII][FeII]/(1+K[FII]) The pseudo-first-order rate constants determined at high [Fell] have been resolved into k and K, and their independent temperature dependence has been studied. The results are totally consistent with an inner-sphere electron-transfer process in which the precursor complex contains a double bridge using both the cis-chloro ligands and in which the iron atom is octahedrally coordinated.

Electron-Transfer Reactions in Non-Aqueous Media. V. Solvent Effects in the Reduction of CoN3(NH3)52+ by Iron(II)

1979 ◽  
Vol 32 (10) ◽  
pp. 2139 ◽  
Author(s):  
TJ Westcott ◽  
DW Watts
Keyword(s):  
Electron Transfer ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Transfer Reactions ◽  
Tetrahedral Coordination ◽  
First Order ◽  
Precursor Complex ◽  
Stage Process ◽  
Pseudo First Order ◽  
Reversible Formation

The reduction of CoN3(NH3)52+ by iron(II) is rate-determined by a two-stage process involving the reversible formation of an azide-bridged precursor complex prior to electron transfer in each of the solvents water, Me2SO, aqueous Me2SO and HCONMe2. The activation parameters in H2O and Me2SO, and the trends shown with increasing Me2SO concentrations in aqueous Me2SO, are similar to the properties of the previously studied CoCl(NH3)52+ and CoBr(NH3)52+ systems and contrast with the reduction of COF(NH3)52+. The results are consistent with a bridged precursor complex octahedral at both the iron and cobalt atoms in water but with tetrahedral coordination about the iron in Me2SO. In HCONMe2, as in the reduction of COF(NH3)52+, COCl(NH3)52+ and COBr(NH3)52+, the precursor complex is a significant part of the reacting solutions, and as a result the experimental pseudo-first-order rate constants for the loss of CoIII are not linearly dependent on the concentration of FeII. The initial spectra of the reacting solutions in this system also indicate significant concentrations of the precursor complex.

Electron-Transfer Reactions in Non-Aqueous Media. IV. A Temperature-Dependence Study of the Reduction of CoCl(NH3)52+ by Iron(II) in N,N-Dimethylformamide

1979 ◽  
Vol 32 (7) ◽  
pp. 1425 ◽  
Author(s):  
KR Beckham ◽  
DW Watts
Keyword(s):  
Electron Transfer ◽  
Temperature Dependence ◽  
Equilibrium Constant ◽  
Rate Constant ◽  
Iron Atom ◽  
Rate Constants ◽  
Aqueous Media ◽  
Transfer Reactions ◽  
Complex Functions ◽  
Temperature Dependences

A detailed study has been made of the temperature dependence of the rate of reduction of CoCl-(NH3)52+ by iron(II) in N,N-dimethylformamide. The observed rate constants (kobs) for this reaction are complex functions of an equilibrium constant (K) for the formation of a bridged intermediate, the rate constant for electron transfer in this bridged intermediate (k), and the iron(II) concentration. From studies of the dependence of kobs on iron(II) concentration at five temperatures the temperature dependences of both K and k have been resolved, yielding respectively ΔH� -20k�12 kJ mol-1, ΔS� -44�40 J K-1 mol-1 and ΔH* 107�4 kJ mol-1, ΔS* 57�16 J K-1 mol-1. The results are interpreted in terms of a bridged intermediate in which the iron atom is tetrahedrally coordinated.

Thermodynamics and kinetic investigation of electron transfer reactions of surfactant cobalt(iii) complexes containing diimine ligands with iron(ii) in the presence of liposome vesicles and amphiphilic salt media

RSC Advances ◽  
2014 ◽  
Vol 4 (99) ◽  
pp. 56068-56073 ◽  
Author(s):  
Karuppiah Nagaraj ◽  
Subramanian Sakthinathan ◽  
Sankaralingam Arunachalam
Keyword(s):  
Electron Transfer ◽  
Absorption Spectroscopy ◽  
Order Conditions ◽  
Transfer Reactions ◽  
Kinetic Investigation ◽  
First Order ◽  
Diimine Ligands ◽  
Different Temperatures ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of reductions of surfactant cobalt(iii) complexes by iron(ii) in liposome vesicles (DPPC) and amphiphilic salt ((BMIM)Br) were studied at different temperatures by UV-Vis absorption spectroscopy method under pseudo first order conditions using an excess of the reductant.

Electron-transfer reactions in non-aqueous media. II. Reduction of CoF(NH3)52+, CoCl(NH3)52+ and CoBr(NH3)52+ by iron(II) in dimethyl sulphoxide-water mixtures

1976 ◽  
Vol 29 (1) ◽  
pp. 97 ◽  
Author(s):  
BA Matthews ◽  
DW Watts
Keyword(s):  
Electron Transfer ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Solvent Composition ◽  
Dimethyl Sulphoxide ◽  
Transfer Reactions ◽  
Octahedral Coordination ◽  
Electron Transfer Reactions ◽  
Kinetics Of

The kinetics of the reduction of the cobalt(111) octahedral complexes, CoF(NH3)52+, CoCl(NH3)52+ and CoBr(NH3)52+, by iron((11) in various Me2SO-H2O mixtures have been studied over a range of temperatures. The activation parameters obtained for the chloro and bromo systems are consistent with a change in the stereochemistry of the iron (11) atom in the bridged intermediate from octahedral in water to tetrahedral with increasing Me2SO concentration. The fluoro system, however, has activation parameters which are less sensitive to solvent composition and consistent with the iron(11) atom maintaining octahedral coordination.

scholarly journals Kinetics of dechlorination of atrazine using tin (SnII) at neutral pH conditions

2020 ◽  
Vol 3 (1) ◽  
pp. 49
Author(s):  
Vijay Kumar ◽  
Simranjeet Singh
Keyword(s):  
Aqueous Media ◽  
Spectrometric Analysis ◽  
First Order ◽  
Neutral Ph ◽  
First Order Kinetics ◽  
Condi Tions ◽  
Ph Conditions ◽  
Pseudo First Order ◽  
Reaction Constants ◽  
Kinetics Of

Atrazine is a broad spectrum herbicide of triazine family. It is a chlorine-containing molecule and it can persist in environment. Chemical and biochemical techniques are the main techniques used to decompose the chemicals. In pre-sent study, the dechlorination of atrazine (Atr) via reaction with Sn(II) ion under aqueous media at neutral pH condi-tions was studied. The observed dechlorinated metabolite was 4-Ethylamino-6-isopropylamino-[1,3,5]triazin-2-ol. Identification of dechlorinated product of Atr was performed by using spectroscopic (FTIR) and mass (ESI-MS) spectrometric analysis. The kinetics of the dechlorination of Atr was measured by using pseudo-first order kinetics. The observed reaction constants was, kobs = 6.11x10-2 (at 430 mg/ L of Atr), and kobs = 6.14 x10-2 (at 215 mg/ L of Atr). The calculated half-life (t1/2) period was, t1/2 = 0.204 d (at 430 mg/ L of Atr), and t1/2 = 0.205 d (at 215 mg/ L of Atr).

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