New Ru(III) 2,6-Bis(2-Benzimidazolyl)Pyridine Complexes Bearing P-Sub-Benzyl Thiosemicarbazones Schiff Base: Synthesis, Characterization, DNA Binding and Anti-cancer Activity.

The six mononuclear Schiff's base Ru(III) complexes viz., [Ru(BZP)(LA)].2NO (MRA), [Ru(BZP)(LB)].2NO (MRB), [Ru(BZP))(LC)].2NO (MRC), [Ru(BZP))(LD)].2NO (MRD), [Ru(BZP)(LE)].2NO (MRE) and [Ru(BZP)(LF)].2NO (MRF), were synthesized using of (BZP=2,6-bis(2-benzimidazolyl)pyridine and p-sub-benzylthiosemicarbazones (BTS) [(Sub=4-NO (LA), 4-N(CH) (LB), 4-Cl (LC), 4-OCH (LD), 4-OCHPh (LE), and 4-OH (LF)] as an ancillary ligands. The thiosemicarbazones ligands (LA-LF) were obtained by the condensation of p-substituted benzaldehyde and thiosemicarbazide. These complexes were characterized by elemental analysis, IR, ESR, ESI-MS, electronic absorption spectroscopy. The geometry was optimized by theoretical calculation using DFT and structure reveals that MRA-MRF adopt octahedral geometry. Further, the complexes were examined for anti-cancer against Leukemia cancer cell line K562 and shown significant responses to these cells. Moreover, DNA binding studies were conducted with all complexes MRA-MRF and the binding constant (K) were found i.e., 1.10×10, 1.54×10, 2.87×10, 1.67×10, 1.98×10 and 1.59×10, respectively. It was found that DNA binds in intercalation mode which is also validated by the docking studies.