Synthesis, structure, and cytotoxicity of some triorganotin(iv) complexes of 3-aminobenzoic acid-based Schiff bases

Abstract

Six new triorganotin(iv) complexes of 3-aminobenzoic acid-based Schiff bases, 3-(R′-CH═N)C6H4COOSnR3 (1–6) (R′, R = 5-Br-2-HOC6H3, Ph (1); 3,5-Br2-2-HOC6H2, Ph (2); 4-NEt2-2-HOC6H3, Cy (3); 3-OCH3-2-HOC6H3, Cy (4); 2-HOC10H6, Ph (5); 2-HOC10H6, Cy (6)), have been synthesized by the one-pot reaction of equimolar 3-aminobenzoic acid, substituted 2-hydroxybenzaldehyde (or 2-hydroxy-1-naphthaldehyde) and triorganotin(iv) hydroxide, and characterized by elemental analysis, FT-IR, NMR spectroscopy, and X-ray single crystal diffraction. The NMR data (1 J(119Sn–13C) and 119Sn chemical shifts) suggested that these organotin(iv) complexes are all four-coordinated in CDCl3 solution. In the crystalline state, the tin atoms in 1–4 and 6 are four-coordinated and possess a distorted tetrahedral geometry. Complex 5 with crystalline solvents (CH3OH and CHCl3) exhibits a zigzag chain, and the five coordination atoms on the tin atom are arranged in a trigonal bipyramidal geometry in which the carboxylate oxygen atom and the phenolic oxygen atom of the adjacent ligand occupy the axial positions. In all complexes, the 3-(arylmethyleneamino)benzoate ligands are coordinated with tin atoms in monodentate mode. Their cytotoxicity against two human cancer cell lines (A549 and HeLa), UV-Vis, and fluorescence have been determined, and the results reveal that complexes 1–6 have higher cytotoxicity than cisplatin and may be explored for potential blue luminescent materials.

Keywords

• organotin(iv) complex
• 3-aminobenzoic acid
• schiff base
• crystal structure
• cytotoxicity