New diorganotin(IV) complexes with some Schiff bases derived from β-diketones: synthesis, spectral properties, thermal analysis, and antibacterial activity

Abstract

The Schiff bases H2La, H2Lb, and H2Lc have been prepared from the reaction of 2-amino-4-chlorophenol with acetylacetone, benzoylacetone, and dibenzoylmethane, respectively. Organotin(IV) complexes [SnPh2(La)] (1), [SnPh2(Lb)] (2), [SnPh2(Lc)] (3), and [SnMe2(Lc)] (4) have been synthesized from the reaction of SnPh2Cl2 and SnMe2Cl2 with these Schiff bases. The synthesized complexes have been characterized by elemental analysis and FT-IR, 1H, 13C, and 119Sn NMR spectroscopy. Spectroscopic data suggest the Schiff bases are completely deprotonated and coordinated tridentate to tin via imine nitrogen and phenolic and enolic oxygen atoms; the coordination number of tin is five. Thermal decomposition of the complexes has been studied by thermogravimetry. The in vitro antibacterial activities of the Schiff bases and their complexes have been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. H2La, H2Lc, and all complexes exhibited good activities and have potential as drugs.