摘要

The formation constants K (ML) of Clarithromycin (CLA) and Roxithromycin (ROX) with Fe(III) and Fe(II) ions in methanol have been determined at various temperatures using a conductometric technique. The interaction yields complexes with metal-to-ligand compositions of 1:1. The conductivity data were analyzed using a computer program based on 1:1 stoichiometry from which the stability constants and the limiting molar conductance were obtained. The stability of these complexes was found to increase with temperature. Compared with Fe(II), Fe(III) forms more stable complexes with ROX and CLA. The values of the thermodynamic parameters enthalpies (Delta H (a similar to)), entropies (Delta S (a similar to)), and the derived Gibbs energies (Delta G (a similar to)) were deduced from the dependence of the formation constants on temperature. The positive values of Delta H (a similar to) and Delta S (a similar to) indicate that the complexation processes is enthalpically unfavorable but entropically favored. The negative values of Delta G (a similar to) show the ability of the studied ligand to form stable complexes and that the complexation process is favorable.

  • 出版日期2012-8