Facile synthesis and grafting of N₂O₂-Cu(II) Schiff base complex onto graphene oxide surface: Aspects of its antimicrobial, anticancer, antiCOVID-19 and photodegradation of methylene blue

In this study, a facile synthesis and grafting method is reported for tetradentate Cu(II) Schiff base complex onto the surface of graphene oxide (GO). The Schiff base Cu-complex was synthesized through the condensation reaction between 2,3-diamino pyridine and 2-hydroxy-1-naphthaldehyde, followed by the addition of Cu(II) ion to afford N2O2-Cu(II) complex. The GO was prepared through a modified Hummers' method and characterized using various spectroscopic and microscopic techniques. The Schiff base Cu-complex was then grafted onto the surface of GO via a simple solution-phase reaction, resulting in the formation of N2O2-Cu(II) Schiff base/GO composite. The fabricated composite was characterized using FTIR spectroscopy, UV-vis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Importantly, the prepared N2O2-Cu(II) Schiff base complex exhibited excellent DNA interaction as well as efficient antimicrobial and anticancer activities. Additionally, it demonstrated potent anticancer activity against hepatocellular carcinoma cells (HepG-2), and colon cancer cells (HCT-116) and exhibited promising activity against the COVID-19 receptor (PDB ID: 6LU7) along with the human DNA receptor (PDB ID: 1BNA). Furthermore, this fabricated heterogeneous catalyst showed enhanced photodegradation of MB with approximate to 92% conversion and four times recyclability. The overall results suggest that the Cu(II) Schiff base/GO composite has potential applications in various medical and environmental fields, including photodegradation/elimination of harmful organic dyes for water treatment applications.