Binary and ternary nickel (II) complexes with 2-methylquinoline-8-carboxylic acid and some amino acids HenríquezYurgenis HernándezLino UrdanetaNeudo GalarragaElier SantorelliAngel LandaetaVanessa R. Rodríguez-LugoRafael E. AraujoMary Lorena LubesVito 2019 <p>In this work, the ligand 2-methylquinoline-8-carboxylic acid (HL) was prepared using a modification of a previous protocol, and its protonation constants were studied. The stability constants of the binary nickel (II) – ligand L<sup>−</sup> and the ternary nickel (II) – ligand L<sup>−</sup> – amino acids (B<sup>−</sup>) systems were investigated. The amino acids selected for this study were glycine (Gly), α-alanine (αAla), β-alanine (βAla), proline (Pro), serine (Ser), methionine (Met), threonine (Thr), phenylalanine (Phe), aspartic acid (Asp), glutamic acid (Glu), histidine (His) and cysteine (Cys). The stability constants were pH-metrically measured in 1.0 mol dm<sup>−3</sup> NaCl at 25°C. The least squares program LETAGROP was used for the analysis of the potentiometric data. Species distribution diagrams as a function of pH are briefly discussed.</p>