Synthesis, spectral characterisation of novel azo–dye 4-((E)-(2-hydroxy-3-methoxy-5-((E)-thiazol-2-yldiazenyl)benzylidene)amino)-1,5-dimethyl-2-phenyl-1H-Pyrazol-3(2H)-One and its Transition Metal Complexes; Differential Pulse Voltammetric Detection of Nitrite and its Biological Activities

The novel azo-azomethine 4-((E)-(2-hydroxy-3-methoxy-5-((E)-thiazol-2-yldiazenyl)benzylidene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (HTDP) and its Cu(II), Co(II) and Ni(II) complexes were synthesized, and their structure was confirmed by using physicochemical techniques. The spectrochemical data indicate that the synthesized ligand is tridentate in nature. The antimicrobial, anti-diabetes (A-DM), and anti-mycobacterium tuberculosis (M-TB) activities against ligands and their metal complexes were screened. The complexes exhibited enhanced bio-efficiency inhibitory results when compared to the HTDP. Excess nitrate poses harmful effects on the ecological system and causes the blue baby syndrome. The modified glassy carbon electrode prepared using Co(HTDP)2 is used for electrochemical sensing of nitrate under different concentrations and displayed good electro-catalytic activity with long linear range (10-80 µmolL-1), sensitivity (0.172 μAμM−1 cm-2) and the LOD (limit of detection) found to be 3.333 µML-1 in PBS (pH 7) Further, the prepared sensor has more stability and showed less pouling property. © 2023 by the authors. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).