1. Thermodynamic Investigation andMixed Ligand Complex Formation of 1,4-Bis-(3-aminopropyl)-piperazine and Biorelevant Ligands.
- Author
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El-Sherif, Ahmed A., Shehata, Mohamed R., Shoukry, Mohamed M., and Barakat, Mohammad H.
- Subjects
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THERMODYNAMICS , *LIGANDS (Chemistry) , *METAL complexes , *PIPERAZINE , *PROTON transfer reactions , *METAL ions , *AQUEOUS solutions - Abstract
Thermodynamic parameters for protonation of 1,4-bis(3-aminopropyl)-piperazine (BAPP) and itsmetal complexation with some divalent metal ions were determined in aqueous solution at constant ionic strength (0.1M NaNO3) using a potentiometric technique. The order of -ΔG0 and -ΔH0 was found to obey Co2+ < Ni2+ < Cu2+ > Zn2+, in accordance with the Irving-Williams order. The formation equilibria of zinc (II) complexes and the ternary complexes Zn(BAPP)L, where L = amino acid, amides, or DNA constituents), have been investigated. Ternary complexes are formed by a simultaneous mechanism. The concentration distribution of the complexes in solution was evaluated as a function of pH. Stoichiometry and stability constants for the complexes formed are reported and discussed. The stability of ternary complexes was quantitatively compared with their corresponding binary complexes in terms of the parameter Δlog K. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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