Copper based azo dye catalysts for phenoxazinone synthase mimicking efficiency: Structure characterization and bioactivity evaluation

Abstract

The ligands, 4-(2-Hydroxy-naphthalen-1-ylazo)-N-thiazol-2-yl-benzenesulfonamide (H2TNBS) and N-(3,4-Dimethyl-isoxazol-5-yl)-4-(2-hydroxy-naphthalen-1-ylazo)-benzenesulfonamide (H2INBS), synthesized in the current investigation have been characterized and used for synthesizing divalent copper complexes by their reaction with a number of Cu(II) salts. Spectral and analytical methods have been applied for structures’ investigation. Morphology of the synthesized compounds have been investigated using TEM technique which joint with the results of X-ray powder diffraction spectroscopy confirmed the precipitation of both ligands and their complexes in the nanometric scale. Formation of the synthesized complexes in 1:1 or 2:1 (M:L) ratio was asserted by analytical results. Ultraviolet–visible spectra and magnetic moment were used to demonstrate the geometry around the Cu centers to be 4 coordinated square planar. The compounds under interest have been screened against selected microorganisms including Gram-positive and Gram-negative bacteria, unicellular and multicellular fungus showing, in most compounds, enhancement of activity upon chelation. The cell lines A-549 (human lung cancer cell line) and Panc-1 (human pancreatic cancer cell line) have been chosen to check the antitumor efficiency of the synthesized compounds; Vinblastine was used as standard. Finally, the Cu(II) chelates were investigated toward mimicking the protein phenoxazinone synthase using o- aminophenol (OAP) as substrate and DMF is the solvent. The results presented extremely high activity for the chloro complex 4 and nitro complex 6 with TOF numbers from 390.48 and 467.01 h−1, respectively. The least activity afforded by the acetato complexes 2 and 5.