Kinetics of displacement of dimethyl sulphoxide (dmso) from [Pt(N–N)(dmso)X]+by X–[N–N = 1,10-phenanthroline, 2,2′-bipyridyl, or 2,2-bis(2′-pyridyl)-1,3-dioxolane; X = Cl or Br]

1990 ◽  
pp. 401-405 ◽  
Author(s):  
Giuliano Annibale ◽  
Luciano Canovese ◽  
Gavino Chessa ◽  
Lucio Cattalini ◽  
Martin L. Tobe
Keyword(s):  
Dimethyl Sulphoxide ◽  
Kinetics Of

Kinetics and Mechanism of Oxidation of Dimethyl Sulphoxide by Mono- and Di-Substituted N,N-Dichlorobenzenesulphonamides in Aqueous Acetic Acid

2003 ◽  
Vol 58 (8) ◽  
pp. 787-794 ◽  
Author(s):  
B.Thimme Gowda ◽  
K. L. Jayalakshmi ◽  
K. Jyothi
Keyword(s):  
Acetic Acid ◽  
Benzene Ring ◽  
Dimethyl Sulphoxide ◽  
Aqueous Acetic Acid ◽  
Isokinetic Temperature ◽  
Free Energies ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of

In an effort to introduce N,N-dichloroarylsulphonamides of different oxidising strengths, four mono- and five di-substituted N,N-dichlorobenzenesulphonamides are prepared, characterised and employed as oxidants for studying the kinetics of oxidation of dimethyl sulphoxide (DMSO) in 50% aqueous acetic acid. The reactions show first order kinetics in [oxidant], fractional to first order in [DMSO] and nearly zero order in [H+]. Increase in ionic strength of the medium slightly increases the rates, while decrease in dielectric constant of the medium decreases the rates. The results along with those of the oxidation of DMSO by N,N-dichlorobenzenesulphonamide and N,N-dichloro-4- methylbenzenesulphonamide have been analysed. Effective oxidising species of the oxidants employed in the present oxidations is Cl+ in different forms, released from the oxidants. Therefore the introduction of different substituent groups into the benzene ring of the oxidant is expected to affect the ability of the reagent to release Cl+ and hence its capacity to oxidise the substrate. Significant changes in the kinetic and thermodynamic data are observed in the present investigations with change of substituent in the benzene ring. The electron releasing groups such as CH3 inhibit the ease with which Cl+ is released from the oxidant, while electron-withdrawing groups such as Cl enhance this ability. The Hammett equation, log kobs = −3.19 + 1.05 σ , is found to be valid for oxidations by all the p-substituted N,N-dichlorobenzenesulphonamides. The substituent effect on the energy of activation, Ea and log A for the oxidations is also analysed. The enthalpies and free energies of activation correlate with an isokinetic temperature of 320 K.

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.

Copper(II)-promoted solvolyses of nickel(II) complexes. II. Tridentate and tetradentate Schiff base ligands containing remote substituents

1973 ◽  
Vol 26 (7) ◽  
pp. 1459 ◽  
Author(s):  
WW Fee ◽  
JD Pulsford ◽  
PD Vowles
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Rate Constants ◽  
Dimethyl Sulphoxide ◽  
Common Mechanism ◽  
Schiff Base Ligands ◽  
Dissociative Mechanism ◽  
Tetradentate Schiff Base ◽  
Kinetics Of ◽  
Mechanism Operative

The kinetics of copper(II)-promoted solvolyses of two series of nickel(II) complexes containing polydentate Schiff bases with various remote substituents, in dimethyl sulphoxide (dmso), are discussed from the viewpoints of rate constants and of enthalpies and entropies of activation. Appearance of an isokinetic relation for the tridentate (ONS donors) reactants may indicate a common mechanism operative within this reactant series. Rate constants appear related to σp values in such a way that a dissociative mechanism appears important for the tridentate reactants, while characterization in terms of associative behaviour is indicated for the tetradentates.

scholarly journals The effect of solvent on the kinetics of the oxidation of 3-methyl-2,6-diphenyl-piperidin-4-one by quinolinium fluorochromate in aqueous organic media

2001 ◽  
Vol 66 (6) ◽  
pp. 359-365 ◽  
Author(s):  
Kuppanagounder Elango
Keyword(s):  
Aqueous Solutions ◽  
Multiple Regression ◽  
Dominant Role ◽  
Dimethyl Sulphoxide ◽  
Organic Media ◽  
Regression Equations ◽  
Effect Of Solvent ◽  
Tert Butanol ◽  
Kinetics Of ◽  
Quinolinium Fluorochromate

The kinetics of the oxidation of 3-methyl-2,6-diphenyl-piperidin-4-one by quinolinium fluorochromate (QFC) have been investigated in aqueous solutions of dimethyl sulphoxide, 1,4-dioxane, tert-butanol and acetone. The influence of the added co-solvent on the reactivity were analysed in the light of various simple and multiple regression equations, viz the Laidler-Eyring, Grunwald-Winstein, Swain and Kamlet-Taft equations. The obtained results showed that the solvation phenomenon plays a dominant role on the reactivity.

Kinetics of the hydrolysis of acetic anhydride and the reaction of 4-nitrophenyl acetate with imidazole in aqueous-organic mixed solvents

1974 ◽  
Vol 27 (7) ◽  
pp. 1423 ◽  
Author(s):  
DG Oakenfull
Keyword(s):  
Acetic Anhydride ◽  
Organic Solvent ◽  
Transition State ◽  
Activity Coefficients ◽  
Butyl Alcohol ◽  
Dimethyl Sulphoxide ◽  
Kinetics Of Hydrolysis ◽  
State Activity ◽  
Kinetics Of ◽  
Hydrolysis Of

With the general aim of elucidating the role of water structure in the kinetics of hydrolysis, a comparative study has been made of the kinetics of the hydrolysis of acetic anhydride and the reaction of 4-nitrophenyl acetate with imidazole in mixtures of water with ethanol, t-butyl alcohol, dimethyl sulphoxide and dioxan. Both rate constants were always reduced by the addition of organic solvent. Transition state activity coefficients were measured for both reactions in dimethyl sulphoxide-water mixtures and compared with the activity coefficient of phenylalanine (a model zwitterionic transition state). Activation parameters were measured for the hydrolysis of aceticanhydride in t-butyl alcohol-water and dimethyl sulphoxide-water mixtures. Semilogarithmic plots of rate constant against Winstein's Y-value were non-linear for some of the solvents and this fact, coupled with the effect of dimethyl sulphoxide on the transition state activity coefficients, leads to the conclusion that specific interactions of the solvent with the reactants and with the transition state could be of major importance in controlling the reaction rate.There was no obvious relationship between the effect of an organic solvent on the kinetics of hydrolysis of acetic anhydride and its effect on the structure of water.

Sign in / Sign up

Export Citation Format

Share Document