Synthesis, structure, preliminary antimicrobial and antimalarial studies of 1,1′-(piperazine-1,4-diyl)bis(2-phenylethan-1-one) and its lanthanide, Ce(III), Pr(III), and Nd(III) complexes

Abstract

A dione ligand, 1,1′-(piperazine-1,4-diyl)bis(2-phenylethan-1-one) derived from the reaction of phenylacetylchloride with piperazine and the lanthanides, Ce(III), Nd(III), and Pr(III) complexes of general formula [LnL(NO3)2]NO3 were synthesized. The compounds were characterized by conventional NMR, Mass Infra-Red and UV–vis spectroscopic techniques, melting point, elemental analysis, conductivity, thermogravimetric analysis, magnetic susceptibility, and single X-ray structure determination of the ligand. In vitro, antimicrobial studies indicated that the ligand is active against Staphylococcus aureus, Bacillus Sublitis, Salmonella typhi, and Streptococcus pneumonae. The Ce(III) and Pr(III) complexes were active against all the microorganisms except A. Niger and Pseudomonas aeruginosa whereas the Ce(III) complex showed activity against Staphylococcus aureus, Bacillus Sublitis, and Streptococcus pneumonae. The In vivo anti-plasmodial assay of infected rats indicated that the ligand and Nd(III), Pr(III) complexes have high antiplasmodial potency in comparison to the antimalarial medicine Artesunate. In corroboration with findings on the enhanced antimicrobial properties of the complexes, binding energies from molecular docking correlated strongly with the inhibition zone diameter for Staphylococcus aureus and density functional theoretical studies suggest the presence of the metals account for the improved properties in the following order: Nd(III) > Pr(III) > Ce(III).