Evolution of palladium(II) complexes as DNA intercalator and artificial metallonuclease

Abstract

New complexes of Pd(II) with only thiophene derivatives and also thiophene derivatives with benzene-1,2-dithiol (bdt) were synthesized and deliberately investigated. All synthesized complexes were characterized by elemental analysis, conductivity measurements, thermogravimetric analysis, magnetic moment measurements, electronic spectra, 1H NMR, FT-IR and LC–MS. Antibacterial study was carried out against pathogenic bacteria like Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Serratia marcescens, and Pseudomonas aeruginosa. Toxic property of synthesized complexes was determined using in vitro brine shrimp (Artemia cysts) lethality bioassay technique. The complexes were screened for DNA-binding study using UV–Vis absorption titration and relative viscosity measurement study. Hypochromism with bathochromic shift in absorption titration and increase in viscosity indicate the intercalative binding of the complexes with CT-DNA. Intercalative mode of binding of the complex with CT-DNA was also shown by molecular modelling. DNA cleavage study of the complexes was performed by gel electrophoresis experiment using pUC19 DNA. All complexes are very effective artificial metallonuclease, which promote the cleavage of DNA from supercoil to open circular form. Anti-tuberculosis activity was tested using Mycobacterium tuberculosis H37RV bacteria by LJ medium conventional method.