Thermodynamic studies of 2-(5-bromo-2-pyridylazo)-5-diethylamino)phenol Cu(II), Co(II), Ni(II) and Zn(II) complexes

Topçu S., Menek N., Eren E.

Dyes and Pigments, vol.50, no.1, pp.29-33, 2001 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 50 Issue: 1
  • Publication Date: 2001
  • Doi Number: 10.1016/s0143-7208(01)00027-4
  • Journal Name: Dyes and Pigments
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.29-33
  • Keywords: Complex formation, Pyridylazo, Spectrophotometric, Stability constant
  • Ondokuz Mayıs University Affiliated: Yes


The metal-ligand mole ratios and the stability constants of the Cu(II), Co(II), Ni(II) and Zn(II) complexes at 2-(5- bromo-2-pyridylazo)-5-diethylamino)phenol were determined using a spectrophotometric method at different temperatures (20, 30, 40 and 50±0.1 °C) and ionic strengths (0.05, 0.1 and 0.2) in 30% (v/v) aqueous ethanol. Plots of thermodynamic stability constants at zero ionic strength (In K°) versus T-1 gave linear curves; the ensuing complex formation (ΔH° and ΔS°) values calculated from these plots. The changes in free energy for each metal-ligand system were evaluated. © 2001 Elsevier Science Ltd. All rights reserved.