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1 H NMR Study of Hindered Internal Rotation of Tetramethylthiuram Disulfide in Binary Dimethyl Sulfoxide‐Chloroform Mixtures
Author(s) -
Bordbar Maryam,
Bijanzadeh Hamid Reza,
Alizadeh Naader
Publication year - 2004
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200400070
Subject(s) - chemistry , chloroform , dimethyl sulfoxide , arrhenius plot , enthalpy , proton nmr , sulfoxide , solvent , arrhenius equation , entropy of activation , stereochemistry , organic chemistry , reaction rate constant , thermodynamics , activation energy , kinetics , physics , quantum mechanics
Hindered internal rotation about the C‐N single bonds joining the thiuram disulfide was studied by 1 H NMR complete line‐shaped analysis in different dimethyl sulfoxide‐chloroform (DMSO‐CDCl 3 ) mixtures. From the temperature dependence of methyls proton spectra, activation parameters (E a , ΔH ≠ , ΔS ≠ , and ΔG ≠ ) were obtained. The Arrhenius plots showed a distinct isokinetic temperature at about 35 °C at which the exchange rate is more or less independent of the solvent composition. The resulting ΔH ≠ against TΔS ≠ plot showed a firmly good linear correlation, indicating the existence of an enthalpy‐entropy composition in an exchange process.