Spectrophotometric Determination of the Stability Constants of Co(II) and DPKBH (Di-2-Pyridyl Ketone Benzoylhydrazone)
Abstract
In order to have more information about the thermodynamic properties of the complexes formed by Cobalt(II) and DPKBH (di-2-pyridyl ketone benzoylhydrazone) and for the development of speciation methods for cobalt, the respective stepwise formation constants were determined in ethanolic solution 50% (V/V), at pH 5.3 and 25.0°C. The spectrophotometric method of corresponding solutions was used and the following overall formation constants were obtained: β_1 = 5.305 × 10^6 M^(−1) and β_2 = 8.476 × 10^(10) M^(−2). The molar absorptivities of the 1:1 (ε_1) and 1:2 (ε_2) complexes (Co(II):DPKBH) were determined to be 4.475 × 10^3 and 2.994 × 10^4 (M^(−1)cm^(−1)), respectively. The calculated distribution diagram shows the percentage of the species at equilibrium as a function of the free DPKBH concentration.
Additional Information
© 1995 by Marcel Dekker, Inc. Date Received: May 25, 1995, Date Accepted : July 5, 1995. M. E. V. Suárez-Iha is grateful to the Fundação de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) for the financial support. We are also grateful to the NSF (ATM 9Q15775) for providing the financial resources for this project.Additional details
- Eprint ID
- 59369
- Resolver ID
- CaltechAUTHORS:20150810-152946428
- Fundação de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)
- ATM 9Q15775
- NSF
- Created
-
2015-08-11Created from EPrint's datestamp field
- Updated
-
2023-10-23Created from EPrint's last_modified field