Synthesis, characterization, antimicrobial activity, DFT and molecular docking studies of the N-salicylidene-glycinato and their metal mixed ligand complexes with caffeine

Abstract

Schiff base glycinate derived from the condensation of salicylaldehyde and glycine in basic media have been synthesized the N-salicylidene-glycinato (LH) and characterized by infrared, UV-Visible, NMR and DFT. The mixed Schiff base and caffeine complexes [M (LH)2 (caf)2]; M= Cu(II), Ni(II), Cd(II) and Zn(II) with LH= N-salicylidene-glycinato and caf= caffeine, were prepared and characterized by the molar conductance, FTIR, UV-Visible 1H & 13C NMR and TGA/DTA. The ligand (LH) acts in a chelate manner (NO) donor and coordination of caffeine by N9 through metal ions. The molar conductance reveals that the metal complexes are non-electrolytes. The postulated octahedral structure of the obtained complexes is also confirmed by the spectroscopic data and thermal analysis. The antimicrobial activity of the complexes was evaluated against eight bacteria species and four fungal strains. The results of their tests show that the metal (II) complexes are more effective against several bacterial and fungal strains. The results of the molecular docking show that the mixed Schiff glycine caffeine complexes have good affinity with the protein kinase (CK2).