Density Functional Theory Computations for Design of Salicylaldoxime Derivatives as Selective Reagents in Solvent Extraction of Copper

Abstract

We have performed density functional theory computations to study interactions of salicylaldoxime (SALO) and its derivatives possessing appropriate alkyl group substitution in the main chain (CM-SALO) or side chain (CS-SALO) with copper, zinc and lead divalent ions. The objective of this study was to understand the underlying interaction mechanisms so as to exploit this knowledge in the design and development of selective reagents for solvent extraction. All computations were performed using plane wave ultrasoft pseudopotentials and Perdew–Burke–Ernzerhof generalized gradient approximation as implemented in the Plane Wave Self consistent field code. The relative order of selectivity, as per the computed interaction energies, was found to be: Cu > Zn > Pb. CM-SALO derivatives exhibited stronger interactions as compared to the CS-SALO derivatives. Our findings were consistent with our experimental results reported earlier and were explained by highest occupied molecular orbital–lowest unoccupied molecular orbital and Lowdin charge analyses.