Comparative 4f-4f absorption spectral study for the interactions of Nd(III) with some amino acids: Preliminary thermodynamics and kinetic studies of interaction of Nd(III):glycine with Ca(II)

摘要

Spectral analysis of Nd(III) complexes with some amino acids viz.; glycine, l-alanine, l-phenylalanine and l-aspartic acid in the presence and absence of Ca ~(2+) was carried out in some organic solvents; CH _3OH, CH _3CN, DMF and dioxane using comparative absorption spectra of 4f-4f transitions. The study was carried out by evaluating various energy interaction parameters like Slator-Condon (F _k), Lande factor (ξ _(4f)), nephelauxetic ratio (β), bonding parameter (b ~(1/2)), percent-covalency (δ) by applying partial and multiple regression analysis. The values of oscillator strength (P _(obs)) and Judd-Ofelt electric dipole intensity parameter T _λ (λ = 2, 4, 6) for different 4f-4f transitions have been calculated. On analysis of the variation of the various energy interaction parameters as well as the changes in the oscillator strength (P _(obs)) and T _λ values, reveal the mode of binding with the different ligands. Kinetic studies for the complexation of Nd(III):glycine:Ca(II) have also been discussed at different temperatures in DMF medium and from it the values of activation energy (E _a) and thermodynamic parameters like ΔH°, ΔS° and ΔG° for the complexation are evaluated.