Polymer complexes. LXV. Potentiometry, theoretical and molecular docking studies of azo allylrhodanine derivatives and their metal complexes in monomeric and polymeric forms

摘要

Azo dyes of 3-allyl-5-((4-derivative phenyl)diazenyl)-2-thioxothiazolidin-4-one ligands (HLn) are synthesized and characterized using different spectroscopic techniques. The X-ray diffraction, XRD, pattern of the ligand (HL2) is polycrystalline nature. The geometrical structures of the ligand are carried out by HF method with 3-21G basis set. Molecular docking was used to predict the binding between azo dye ligand and the receptor of prostate cancer mutant 2q7k-hormone and the receptor of breast cancer mutant 3hb5-oxidoreductase. The predicted pK(a) obtained by docking measurements for the ligands are in agreement with experimental values. The predicted and expermently calculated pK(H) values of the ligands increases in the order HL3, HL2 and HL1 as expected from Hammett's constant (sigma(R)). The proton-ligand dissociation constants of HLn and their metal stability constants with Mn2+, Co2+, Ni2+ and Cu2+ have been determined potentiometrically in monomeric and polymeric forms using 2,2'-azobisisobutyronitrile as initiator. The potentiometric studies were carried out in 0.1 M (KCl) and 50% (by volume) DMSO-water mixture. The effect of temperature was studied at 298, 308 and 318 K and the corresponding thermodynamic parameters (Delta G, Delta H and Delta S) were derived and discussed. The dissociation process is non-spontaneous, endothermic and entropically unfavorable. The formation of the metal complexes has been found to be spontaneous, endothermic and entropically favorable. 2016 Elsevier B.V. All rights reserved.