Synthesis, Characterization, DNA Interaction Study, Antibacterial and Anticancer Activities of New Palladium(II) Phosphine Complexes

Abstract

A series of palladium(II) complexes with N,N-dimethylthiourea and phosphines [tri-p-tolylphosphine (Tptp), benzyl(diphenyl)phosphine (Bdp), cyclohexyl(diphenyl)phosphine (Cdp)] were synthesized by the direct reaction of K₂[(PdCl₄)] with the corresponding phosphines and then with N,N-dimethylthiourea at a molar ratio of 1: 2: 2. The general formula of these complexes is [Pd(L1)₂(L₂)₂]Cl₂, where L1 = N,N-dimethylthiourea (Dmtu), L2 = Tptp, Bdp, Cdp. The complexes were characterized by elemental analyses, multinuclear NMR (¹H, ¹³C, ³¹P), and FT-IR. The complex with cyclohexyl(diphenyl)phosphine was also characterized by single crystal X-ray analysis. The spectral and crystallographic data suggest monodentate coordination of dimethylthiourea through the sulfur atom and of the phosphine ligand through the phosphorus atom and distorted square planar environment of palladium(II). The synthesized complexes have been screened for DNAbinding, antibacterial, cytotoxic, and antitumor activities. The complexes show interaction with DNA via intercalative mode. The complexes show good activity against both gram positive and gram negative bacteria as compared to that of a standard drug, Imipenem. Their antitumor activity against MCF7 tumor cell line was found to be comparable with doxorubicin. MTT assay was used to investigate the cytotoxicity of the studied compounds having activity order: 3 > 2 > 1.