1Department of Chemistry, Faculty of Science, Razi University, P.O. Box 67148, Kermanshah, I.R. IRAN
2Department of Chemical Research, ACECR, Kermanshah, I.R. IRAN
The complexation reactions of some transition metal ions and 2-aminopyridine (2-ampy) were studied potentiometrically in aqueous solution at µ=0.1 M and 25 °C. The overall stability constants log β’s of all species are obtained by computer refinement of pH-volume data with using the BEST computer program. Several models were tested and the best one accepted according to the least sum of squared deviations. The main species are MHL, ML, ML2, ML3, and ML2(OH)2. For ML complexes the order of stability confirms the Irwing-Williams series.