Dinuclear bismuth(III) complex constructed by isoniazid-derived Schiff base: Synthesis, crystal structure, and biological activity

A new bismuth(III) Schiff-base complex [Bi-2(HL)(2)(NO3)(4)(CH3OH)]center dot 2CH(3)OH was prepared by reaction of the equivalent molar of Schiff-base ligand [H2L = (E)-N '-(2-hydroxy-4-methoxybenzylidene)isonicotinohydrazide] and Bi (NO3)(3)center dot 5H(2)O with the assistance of mannitol. The complex was structurally characterized by elemental analysis, spectroscopic methods (FT-IR, MS, (HNMR)-H-1, and (CNMR)-C-13) and single crystal X-ray diffraction. The molecular structure of the complex reveals that the ligand forms a 1:1 complex with bismuth(III) ion. It is composed of two 7-coordinated bismuth(III) ions, two tetradentate O2N-donor ligands, four nitrate ions, and three methanol molecules. The complex and its free ligand were evaluated against gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa). The complex was more active than the ligand against all bacterial strains. Their cytotoxic activity was also investigated against SNU-16 cell. The complex is approximately three times more potent than the ligand, with the IC50 values 0.35 and 1.18 mu M for the complex and its ligand, respectively.

Automated summary

A new bismuth(III) Schiff-base complex has been synthesized and structurally characterized. The complex exhibits high activity against bacteria and tumor cells.