Biological assays and theoretical density functional theory calculations of Rh(I), Ir(III), and Ru(II) complexes of chiral phosphinite ligand

Abstract

Four metal complexes, IL-OPPh2-Ru-p-cymene (3), IL-OPPh2-Ru-benzene (4), IL-OPPh2-Ir-Cp* (5), IL-OPPh2-Rh-COD (6), have been evaluated for in vitro antioxidant activity such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and reducing power activity. Maximum scavenging activity (71.43%) was obtained with IL-OPPh2-Ru-p-cymene, whereas IL-OPPh2-Rh-COD showed the highest reducing power ability. The complexes were also studied for their antimicrobial activity against three Gram-positive and three Gram-negative bacteria. In addition, DNA binding of the complexes was evaluated using calf thymus DNA. Both Ru(II) complexes exhibited good DNA-binding activity while the other complexes did not have any activity. Furthermore, ab initio quantum calculations of four complexes were also carried out using density functional theory to better understand their chemical behaviors.