Coordination of new palladium (II) complexes with derived furopyran-3,4‑dione ligands: Synthesis, characterization, redox behaviour, DFT, antimicrobial activity, molecular docking and ADMET studies

Abstract

The synthesis, characterization, theoretical study, electrochemical behaviour and biological activity of new series of Pd (II) complexes were reported with 6-methyl-2-(phenyl(p-tolylamino)methyl)-4H-furo[3,2-c]pyran-3,4(2H)-dione derived ligands. [MLCl2] is the proposed general formula of complexes. The synthesized complexes were prepared and experimentally characterized by elemental analysis, SEM-EDX, FTIR, 1HNMR, UV-Visible spectroscopy, magnetic measurement, conductivity and thermal analysis. FTIR spectroscopy has revealed the coordination mode of complexes through nitrogen and oxygen atoms. The Density Functional Theory calculation was applied to optimize the geometric structure of complexes, whereas Orbital Molecular Frontiers calculations allowed to define their stability. The experimental electronic spectra and magnetic measurement results approved a square planar geometry for all complexes. These results correlate with theoretical calculations. The electrochemical behaviour of ligands and complexes were determined by cyclic voltammetry, which reveal different redox processes of Pd (II) couples for the three complexes. The antimicrobial activity of all compounds was evaluated against different micro-organisms using agar disc-diffusion method. Most of compounds exhibit a remarkable inhibition against standard yeasts and S. aureus Gram positive bacteria. The ADMET study was carried out to predict pharmacokinetic and toxicity of synthesised compounds. Molecular Docking of HL3 and Pd-HL3 against S. aureus was applied in order to study their molecular interactions