Synthesis, characterization, biological activities, crystal structure and DNA binding of organotin(IV) 5-chlorosalicylates

New organotin(IV) carboxylates, R2SnL2 (R=n-Bu: 1), R2Sn(Cl)L (R=n-Bu: 2), and R3SnL (R=Me: 3; n-Bu: 4; Ph: 5) have been synthesized by stirring 5-chloro-2-hydroxybenzoic acid HL with KOH and R2SnCl2 (R=n-Bu)/R3SnCl (R=Me, n-Bu, Ph) in methanol at room temperature. The complexes along with ligand have been characterized by FTIR, (H-1, C-13) NMR, EI-MS, and single-crystal XRD crystallography. FTIR data indicated bidentate coordination of carboxylate. NMR data suggested six- or five-coordinate geometry of organotin(IV) carboxylates. Single-crystal XRD of 1 demonstrated skew-trapezoidal geometry around the tin center, with the basal plane occupied by four oxygens and the two butyl groups lying in distorted axial position. Complexes 1, 2, and 5 exhibited interaction with SS-DNA (salmon sperm) and suggests intercalating mode of binding. The complexes displayed significant antimicrobial activities against bacterial and fungal strains as compared to free ligand. The hemolytic activity of the complexes was lower compared to Triton-X 100 (positive control, 100% lysis) and higher than phosphate-buffered saline (negative control, 0% lysis). Complex 4 was the most potent inhibitor of bacterial/fungal growth.