Three mixed ligand mononuclear Zn(II) complexes of 4-acyl pyrazolones: Synthesis, characterization, crystal study and anti-malarial activity

Three novel mixed ligand Zn(II) complexes {complex 1 = [Zn(L1)(2)(bpy)], complex 2 = [Zn(L2)(2)(bPY)], complex 3 = [Zn(L2)(2)(phen)], where bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline} of 4-(4-chlorobenzoyl)-2-(3-chlorophenyl)-5-methyl-2,4-dihydro-3H-pyrazol-3-one (HL1) and 4-(4-chlorobenzoyl)-5-methyl-2-(p-tolyl)-2,4-dihydro-3H-pyrazol-3-one (HL2) were synthesized and characterized by H-1 and C-13 NMR, FTIR, TG-DTA, UV-Vis, elemental analysis, molar conductance and single crystal X-ray structure determination. Based on analytical and spectroscopic techniques, all the three Zn(II) complexes were found to have a distorted octahedral geometry. The ligands and the complexes were screened for antimalarial activity against plasmodium falciparum. The zinc(II) complexes showed greater antimalarial activity than their parent ligands. (C) 2020 Elsevier Ltd. All rights reserved.