Synthesis, spectral characterization of novel 4-[(E)-(6-amino-4-hydroxypyridin-2-yl)diazenyl]-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one and their transition metal complexes: Biological activities, electrochemical detection of isotretinoin drug

Azo dyes, containing one or more azo groups (–NN–), represent an important class of synthetic colorants widely used in textile, printing, and cosmetic industries due to their vibrant coloration and high colorfastness. Their chemical versatility enables structural modifications to achieve desired optical and physicochemical properties. In addition to their industrial applications, azo dyes can function as ligands in coordination chemistry, forming complexes with transition metals through nitrogen atoms. These metal–ligand interactions significantly influence the electronic, magnetic, and luminescent properties of the resulting complexes, offering potential applications in catalysis, sensors, and optoelectronic devices. However, concerns have arisen over their possible degradation into carcinogenic aromatic amines, prompting regulatory restrictions on certain azo dyes. Furthermore, the compound 5-methyl-2-phenyl-4H-pyrazol-3-one exhibits notable biological activities, including antimicrobial, anti-inflammatory, and antioxidant effects, suggesting its potential for pharmaceutical development. Characterization of synthesized complexes is performed using various spectroscopic techniques, while their biological and electrochemical activities are evaluated through antimicrobial assays, docking studies, and voltammetric techniques. Notably, a modified glassy carbon electrode containing [Co(AMP)₂]/GCE demonstrates effective detection of Isotretinoin across a range of concentrations. These findings highlight the multifunctionality of azo-based compounds and their derivatives, underscoring their relevance in both material science and biomedical research.