Synthesis, structural properties, DFT studies, antimicrobial activities and DNA binding interactions of two newly synthesized organotin(IV) carboxylates

Abstract

Herein, we report the synthesis, characterization and biological evaluations of two novel organotin(IV) carboxylates (1 and 2). The structures of both complexes are confirmed by single crystal X-rays diffraction analysis. Density functional theory (DFT) studies are also executed to compare experimental (X-ray as well as spectroscopic) results with theoretical ones. Excellent correlation is observed between theoretical and experimental results. Furthermore, organotin(IV) carboxylates are evaluated against different bacterial stains (E. coli, S. aureus, K. pneumoniae and B. subtilis) and fungal stains (F. solani, A. fumigatus and A. niger). The complex 1 shows good antibacterial activity against B. subtilis (17 ± 0.32 mm), whereas complex 2 shows good antibacterial activity against E. coli (18 ± 0.41 mm) and B. subtilis (18 ± 0.41 mm). The complex 1 shows significant activity against A. fumigatus (28 ± 0.45 mm) and 2 shows good activity against A. fumigatus (16 ± 0.37 mm). To determine the interaction of organotin(IV) carboxylates with DNA, the interaction studies with salmon sperm DNA (SS-DNA) are also carried out through UV–vis absorption spectroscopy. The Gibbs free energies (ΔG) (−28.02 kJ/mol for complex 1 and -28.43 kJ/mol for complex 2) and high values of binding constants (K) (8.15 × 104 M−1 for complex 1 and 9.62 × 104 M−1 for complex 2) indicate that strong interactions are developed between organotin(IV) carboxylates and SS-DNA.