Speciation study of nickel(II)-1,10-phenanthroline-amino acid ternary complexes in 1.0 M NaCl at 25 °C

Abstract

Ternary Ni(II) complexes formed with 1,10-phenanthroline (Phen) and the amino acids glycine (Gly, HL), α-alanine (Ala, HL), β-alanine (βAla, HL), proline (Pro, HL), phenylalanine (Phe, HL), methionine (Met, HL), serine (Ser, HL) and threonine (Thr, HL) were studied in aqueous solution using 1.0 M NaCl at 25 °C as an ionic medium. The systems were studied by potentiometric measurements. Analysis of the potentiometric data was done with the least-squares-based program LETAGROP, supporting the formation of species Ni(Phen)(HL)²⁺, Ni(Phen)(L)⁺, Ni(Phen)(L)(OH), Ni(Phen)₂(L)⁺ and Ni(Phen)(L)₂. Species distribution diagrams were generated and the relative stabilities were analyzed using Δ log₁₀ K, log₁₀ X and % RS values.

Keywords:

• Nickel(II)
• 1,10-Phenanthroline
• Amino acids
• Potentiometric studies
• Ternary complexes
• Stability constants

Acknowledgements

We thank the Dean of Research and Development of the Simon Bolivar University for financial support to complete this work.

Disclosure statement

No potential conflict of interest was reported by the author(s).