Design and synthesis of tunable schiff base complexes from bis-(2-oxoindolin-3-ylidene)anthracene-9,10-dione: Integrated structural, biological, and molecular modeling insights

Abstract

Three novel compounds, each featuring a tetra-dentate ligand known as 1-((2-oxoindolin-3-ylidene)amino)-2-((2-oxoindolin-3-ylidene)amino)anthracene-9,10-dione (BIA), have been successfully synthesized. These molecules exhibit the unique characteristic of forming complexes with Cu(II), Ru(III), and VO(II) metal ions, resulting in distinct metal-organic structures.Structural characterization was performed using elemental analysis, magnetic properties measurement, FT-IR spectroscopy, and electronic spectroscopy. Moreover, the stoichiometry in solution was determined through both continuous variation and molar ratio analysis. These analyses have shown that the copper and ruthenium complexes exhibit an octahedral geometric configuration. Conversely, the vanadyl (VO) complex demonstrates a distinct square pyramidal structure.Density functional theory (DFT) computations were employed to confirm the geometrical configurations of the prepared complexes. The synthesized BIA ligand and its corresponding metal complexes were assessed for their in vitro antimicrobial. The results indicated that the RuBIA complex emerged as the most efficacious agent against both bacterial and fungal growth, outperforming established medications like Ofloxacin and Fluconazole as standard drugs with sequenceBIA < VOBIA < CuBIA <RuBIAcomplex.Additionally, the study evaluated the in vitro cytotoxicity of the synthesized compounds against Hep-G2, MCF-7, and HCT-116 cancer cell lines. The results suggested that the RuBIA complex had the highest potency (IC50 =3.42–6.45 µg/µl), followed by CuBIA(IC50 =4.42–7.85 µg/µl), and VOBIA(IC50 =5.72–8.35 µg/µl), indicating their potential as promising anticancer agents. The DPPH radical scavenging activity was also assessed, and all complexes displayed greater efficacy than Ascorbic acid. Investigations employing molecular docking methodologies were undertaken to discern the interaction mechanisms of the aforementioned complexes. The findings revealed that the incorporation of metal ions substantially bolstered the molecular affinities, with the sequence of binding potency as follows: RuBIA> CuBIA > VOBIA complex>BIA ligand.