Investigation of derivatized schiff base ligands of 1,2,4-triazole amine and their oxovanadium(IV) complexes: Synthesis, structure, DNA binding, alkaline phosphatase inhibition, biological screening, and insulin mimetic properties

A series of novel azomethine precursors were derivatized by the condensation of 4H-1,2,4-triazole-4-amine with salicylaldehyde (HL (1)) (saltrz), 2,3-dihydroxybenzaldehyde (HL (2)) (dhtrz), 2-hydroxy-1-naphthaldehyde (HL (3)) (ndtrz) and 5-chloro-2-hydroxybenzaldehyde (HL (4)) (cltrz). Subsequently, oxovanadium(IV) complexes of the type [VO(saltrz)(2)] (1), [VO(dhtrz)(2)] (2), [VO(ndtrz)(2)] (3), and [VO(cltrz)(2)] (4) were synthesized by the reactions of vanadyl(V) isopropoxide [VO(OCHMe2)(3)] with the ligands HL (1)-HL (4). The synthesized compounds were characterized by the melting point method, elemental analysis, FT-IR and 1H and C-13 NMR spectroscopies, the molar susceptibility and conductivity methods, and by the thermogravimetry. Ligands HL (3) and HL (4) were also characterized by single crystal analysis. The binding modes of SS-DNA with the compounds were confirmed by the hypochromism and red/blue shift of the UV-Vis spectra. The negative DG values of the compound-DNA adducts show that the binding is a spontaneous process. The complexes were found to be persuasive inhibitors of enzyme alkaline phosphatase (ALP). The in vitro screening of the antimicrobial activities of the synthesized compounds revealed significantly enhanced activities of oxovanadium(IV) complexes as compared to their respective ligands. The promising results were obtained in studying the insulin mimetic of the synthesized compounds.