Synthesis, structural characterization, and properties of triorganotin complexes of Schiff base derived from 3‐aminobenzoic acid and salicylaldehyde or 2,4‐pentanedione

Abstract

Six new triorganotin 3‐(salicylideneamino)benzoates (1a–1c) and 3‐(4‐oxo‐2‐penten‐2‐ylamino)benzoates (2a–2c), 3‐(2‐HOC6H4CH=N)C6H4COOSnR3, and 3‐(CH3COCH=C(CH3)NH)C6H4COOSnR3 (R = Ph, a; Cy, b; Bu, c) have been synthesized by one‐pot reaction of 3‐aminobenzoic acid, salicylaldehyde (or 2,4‐pentanedione), and triorganotin hydroxide and characterized by elemental analysis, infrared, and nuclear magnetic resonance (1H, 13C, and 119Sn) spectra. The crystal structures of 1a, 1b, and 2a–2c have been determined by the single crystal X‐ray diffraction. Complexes 1a and 2a exhibit a 44‐membered macrocyclic tetramer and a polymeric zigzag chain, respectively, in which tin atoms show trans‐[C3SnO2] trigonal bipyramidal geometry with the axial positions being occupied by the carboxylate oxygen atom and the phenolic (or ketone) oxygen atom from another ligand. Complex 1b adopts a distorted tetrahedral geometry at tin, and there are two molecules differing in the relative orientation of the carboxylate toward the imino group. Compounds 2a⋅CH3OH, 2b⋅H2O, and 2c⋅H2O are five‐coordinated mononuclear adducts with one coordinated solvent molecule and display different supramolecular organizations in which there are the centrosymmetric R22(16), R42(22), and R64(34) macrocycle motifs formed by the O–H⋅⋅⋅O, N–H⋅⋅⋅O, and C–H⋅⋅⋅O hydrogen bonds. The fluorescence spectrum indicates that the complexes may be explored for potential blue luminescent materials. Compared to cisplatin, these compounds exhibit enhanced cytotoxic efficacy and can be considered as anticancer agents for further study.