ISSN:
1572-8927
Keywords:
Hydrogen bonds
;
solvent effects
;
solvatochromic parameters
;
m-cresol
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The enthalpies, entropies, and equilibrium constants for the hydrogen bonded complexes of m-cresol with ten bases in cyclohexane solvent have been determined by calorimetric and spectroscopic methods. The logarithm of the equilibrium constant correlates well with the dipole moment of the base and the solvatochromic parameter β which measures the electron donating ability of the base. The enthalpy and entropy data show that the dipole term does not enter into the log K correlation as a consequence of electrostatic interactions between acid and base in the complex. The free base-solvent interaction, which appears to be dipolar in origin, reduces the entropy of the free base and hence contributes to a favorable entropy change for complex formation. The present data are compared to previously reported data obtained in CCl4 solvent. Solvent effects on the thermodynamic parameters in CCl4 and cyclohexane appear to be related to dipolar interactions by m-cresol and the bases with the two solvents.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00646181
Permalink
