Nouveaux ligands bases de Schiff

Abstract

The present work concerns the elaboration and structural characterization, using three analysis techniques; IR and UV-visible spectroscopy, as well as the structural study by X-ray diffraction on single crystal of a series of new Schiff bases namely: • (E)-2-(2,6- dichlorobenzylideneamino)benzonitrile, I-Antha and I-Anthb, • (E)-2-(4- nitrobenzylidene amino)benzonitrile II-Anth, • le (E)-2-(4-nitrobenzylideneamino)benzenesulfonamide III-Sulf, • le (E)-2-(2,4-dichlorobenzylideneamino) benzenesulfonamide IV-Sulf, • le (E)-2-(2- hydroxybenzylideneamino)benzenesulfonamide V-Sulf. et • le (E)-2-(((3,5-dichloropyridine-2-yl-)imino)methyl)phenol VI-APy The structural modification on the different positions of the base molecule, allows to improve its biological profile conferring antibacterial properties. In fact, Schiff bases derived from Sulfanilamide have shown exceptional potency, based on the minimum concentrations of MIC inhibition, which for the majority is very low. On the other hand, the antioxidant activity of our Schiff bases was evaluated by different methods (DPPH•, ABTS+•, the chelation effect, CUPRAC, reducing power, FRC) which allowed us to confirm the antioxidant capacity of the two Schiff bases which have a hydroxyl group. Indeed, the EC50 values for the VI-Apy base were consistently lower than those of V-Sulf and sometimes even lower than the reference antioxidants. This suggests that VI-Apy appears as a more powerful antioxidant agent. On the other hand, a cytotoxicity test is carried out on the larvae of Artemia salina and which has shown that only the derivatives of anthranilonitrile (I-Anth and II-Anth) and o-aminopyridine (VI-Apy) exhibited potent cytotoxicity (LC50 between 44.19 and 69.73 µg/mL), whereas sulfanilamide derivatives (III-Sulf, IV-Sulf and V-Sulf) were non-toxic (LC50> 1000 µg/mL). As a result, they have a positive outlook because they can be used in pharmaceutical applications such as antibacterial agents.