Tin(IV) Complexes With 2‐Formylpyridine Thiosemicarbazones: Structural and Cytotoxic Activity Studies on Bacterial, Fungal, and Cancer Cells

ABSTRACT Tin complexes, Sn(IV)‐TSC 1·MeOH and Sn(IV)‐TSC 2 , with thiosemicarbazones possessing an N 2 S ligation system [ TSC 1 = 4‐(4‐nitrophenyl)‐1‐((pyridin‐2‐yl)methylene)thiosemicarbazide and TSC 2 = 4‐(2‐methoxyphenyl)‐1‐((pyridin‐2‐yl)methylene)thiosemicarbazide] were prepared and structurally characterized. These complexes are found in the space groups P and P 2 1 / n , respectively, with their tin atoms in octahedral environments established by three chlorine atoms and an anionic thiosemicarbazone ligand. All compounds (20 mg/mL in DMSO) were tested for their antibacterial [against Bacillus subtilis , Staphylococcus aureus , Escherichia coli , and Pseudomonas aeruginosa ] and antifungal [against Aspergillus flavus and Candida albicans ] properties. The ligand TSC 2 displayed inhibitions in the S. aureus and E. coli cultures (with zones of 11 and 10 mm, respectively), whereas Sn(IV)‐TSC 1·MeOH and Sn(IV)‐TSC 2 inhibited all bacteria with 11–15 and 14–16 mm, respectively. In the fungal cultures, only Sn(IV)‐TSC 1·MeOH (10 mm) showed an inhibition zone against A. flavus . The ligands' antiproliferative activities were determined against human cancer cells of the lung, breast, liver, and colon, and both ligands afforded the highest activity against the breast MCF‐7 cells. The complexation enhanced the ligands' activities as TSC 1 , TSC 2 , Sn(IV)‐TSC 1·MeOH , and Sn(IV)‐TSC 2 afforded respective IC 50 values of 52.4, 153.7, 18.3, and 63.9 μM. However, against normal baby hamster kidney (BHK) cells, these compounds showed IC 50 data of 54.8, 82.7, 16.1, and 15.3 μM, respectively.