Computer Augmented Modeling of Complexes of L-Phenylalanine and Maleic Acid under Organic Media: Biomimetic Studies

Abstract

Chemical speciation of ternary complexes of Co (II), Ni (II) and Cu (II) ions with L-Phenylalanine and Maleic acid has been studied by Calvin-Wilson technique at different concentration range of 0 - 50% v/v Organic-water mixture maintaining an ionic strength of 0.16 mol·L-1 at 298.0 K. Alkali metric titrations were carried out in different relative concentrations (M:L:X = 1:2.5:2.5, 1:2.5:5.0, 1:5.0:2.5) of metal (M) to phenylalanine (L) to maleic acid (X). The different values of stability constants of ternary complexes were calculated, and various models were refined with MINIQUAD75. The best fit chemical models containing MLXH, MLX and ML2X for Co (II), Ni (II) and Cu (II) species were arrived based on stability statistical parameters. The chemical speciation is discussed based on distribution diagrams, drawn using HYSS HYPERQUAD. Effect of errors in concentration of ingredients on stability constants was also studied.