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

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 [HL1], N-{pyridine-2-ylmethyl}-2-hydroxy-benzylideneamine [HL2], N-{pyridine-2-ylmethyl}-2-hydroxy-5-nitro-benzylideneamine [HL3], N-{pyridine-2-ylmethyl}-2-hydroxy-5-bromo-benzylideneamine [HL4], N-{pyridine-2-ylethyl}-2-hydroxy-5-methoxy-benzylideneamine [HL5], N-{pyridine-2-ylethyl}-2-hydroxy-benzylideneamine [HL6], N-{pyridine-2-ylethyl}-2-hydroxy-5-nitro-benzylideneamine [HL7], N-{pyridine-2-ylethyl}-2-hydroxy-5-bromo-benzylideneamine [HL8], with the general formula [ML2][Y] (M = Al3+, Ga3+, In3+; Y = NO3−, ClO4−) 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 NaClO4) and at 25 °C in methanol. The trend of formation constants of the complexes are as follow:Al5-H>5-NO2>5-Br5-OMe>5-H>5-NO2>5-BrAlso, their cytotoxic activities were evaluated in four various cell lines which showed their moderate cytotoxic effect.

Graphical abstractTwenty four Schiff base complexes of Al(III), Ga(III) and In(III) were synthesised and fully characterized. Stoichiometry of complexes in solution were evaluated with mole ratio and continuous variation methods. The formation constants of ML1 and ML2 complexes were measured spectrophotometrically using SQUAD program. The cytotoxic activities of complexes were tested in four various cell lines which showed moderate cytotoxic effect.Figure optionsDownload full-size imageDownload as PowerPoint slide