Deactivation of the Cobalt Catalyst for the Cyclotrimerization of Acetylenes in Ionic Liquids: Solvent Effects on the Mechanism and Thermal and Pressure Activation Parameters

2011 ◽  
Vol 30 (15) ◽  
pp. 3919-3922 ◽  
Author(s):  
Teresa Avilés ◽  
Susanna Jansat ◽  
Manuel Martínez ◽  
Francisco Montilla ◽  
Carlos Rodríguez
Keyword(s):  
Ionic Liquids ◽  
Solvent Effects ◽  
Cobalt Catalyst ◽  
Activation Parameters

Solvent effects of ionic liquids: investigation of ferrocenes as electrochemical probes

2010 ◽  
Vol 24 (4) ◽  
pp. 327-334 ◽  
Author(s):  
Claudia Bizzarri ◽  
Valeria Conte ◽  
Barbara Floris ◽  
Pierluca Galloni
Keyword(s):  
Ionic Liquids ◽  
Solvent Effects

Substituent and solvent effects on the reaction between 2,6-Di-t-butyl-α-(3,5-di-t-butyl-4-oxocyclohexa-2,5-dien-1-ylidene)-p-tolyloxyl (galvinoxyl) and phenols

1978 ◽  
Vol 31 (6) ◽  
pp. 1201 ◽  
Author(s):  
N Nishimura ◽  
K Okahashi ◽  
T Yukutomi ◽  
A Fujiwara ◽  
S Kubo
Keyword(s):  
Carbon Tetrachloride ◽  
Binary Mixtures ◽  
Solvent Effects ◽  
Rate Constants ◽  
Isotope Effects ◽  
Mixed Solvents ◽  
Transition States ◽  
Activation Parameters ◽  
Substituted Phenols ◽  
Kinetic Behaviour

Rate constants and associated activation parameters for the reaction of galvinoxyl with substituted phenols were obtained in carbon tetrachloride and in cyclohexane-dioxan binary mixtures. Substantial isotope effects were observed for O-deuterated phenols. The rate constants are correlated with σ+ values. These findings are discussed by considering the polar contribution of substituents to the stabilization of the transition states. In the mixed solvents, the kinetic behaviour is well expressed by the equations which are based on the theory of Kondo and Tokura.

Solvent effects on cycloaddition reactions of potent spin-trapping probe N-tert-butylmethanimine N-oxide: A DFT study

2018 ◽  
Vol 17 (04) ◽  
pp. 1850027 ◽  
Author(s):  
Nivedita Acharjee
Keyword(s):  
Solvent Effects ◽  
Function Analysis ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Solvent Polarity ◽  
Spin Trapping ◽  
Complete Agreement ◽  
Methyl Radical ◽  
Global Properties ◽  
Formation Energies

[Formula: see text]-tert-butylmethanimine [Formula: see text]-oxide is a potent spin-trapping probe for biologically important radicals, and this nitrone undergoes complete regioselective cycloadditions to less electron-deficient monosubstituted olefins. In the present study, solvent effects on the cycloaddition of this nitrone to styrene have been theoretically studied in terms of the global properties of the reactants, electrophilic and nucleophilic Parr function analysis and the activation and reaction energies of located transition states and products. Formation energies of optimized radical adducts were computed to determine their stabilities in different solvents. The cycloaddition is predicted to be completely ortho regioselective which is in complete agreement with experiments and involved earlier C–C bond formation owing to the insufficient depopulation of [Formula: see text]-conjugated carbon atom in styrene and shows varying asymmetry indices in different solvents. Decrease in activation parameters and increase in stability of cycloadducts are predicted with decreasing solvent polarity. Aqueous media destabilize the radical adducts as predicted from the calculated formation energy, enthalpy and free energy of reaction. Hydroxyl as well as methyl radical adducts are predicted to be more stable than superoxide anion radical adducts. These predictions are in complete agreement with the experiments.

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