Complexation of Group IIIA metals with asymmetric tridentate ligands: Synthesis, characterization, formation constants and cytotoxicity

Abstract

A series of new aluminum(III), gallium(III) and indium(III) complexes with some tridentate Schiff base, viz., N-{pyridine-2-ylmethyl}-2-hydroxy-5-methoxy-benzylideneamine [HL 1], N-{pyridine-2-ylmethyl}-2-hydroxy-benzylideneamine [HL 2], N-{pyridine-2-ylmethyl}-2-hydroxy-5-nitro-benzylideneamine [HL 3], N-{pyridine-2-ylmethyl}-2-hydroxy-5-bromo-benzylideneamine [HL 4], N-{pyridine-2-ylethyl}-2-hydroxy-5-methoxy-benzylideneamine [HL 5], N-{pyridine-2-ylethyl}-2-hydroxy-benzylideneamine [HL 6], N-{pyridine-2-ylethyl}-2-hydroxy-5-nitro-benzylideneamine [HL 7], N-{pyridine-2-ylethyl}-2-hydroxy-5-bromo-benzylideneamine [HL 8], with the general formula [ML 2][Y] (M = Al 3+, Ga 3+, In 3+; Y = NO 3 −, ClO 4 −) were synthesised and characterized by elemental analysis, 1H NMR, FT-IR, UV–Vis spectrophotometry and mass spectrometry. The thermodynamic formation constants of the complexes were determined spectrophotometrically at constant ionic strength ( I = 0.10 M NaClO 4) and at 25 °C in methanol. The trend of formation constants of the complexes are as follow: Al < Ga < In 5 -OMe > 5 -H > 5 - NO 2 > 5 -Br Also, their cytotoxic activities were evaluated in four various cell lines which showed their moderate cytotoxic effect.