Investigation of the structure, electronic properties and bioactivity of indeno[1,2-b]indolones synthesized via ZrO₂/CuO nanocomposites: a comprehensive study using 2D NMR spectroscopy, DFT analysis and molecular docking

In this study, a green and low-cost ZrO₂/CuO nanocomposite (ZrO₂/CuO NC) was synthesized via a simple co-precipitation method and employed as a heterogeneous catalyst for the one-pot and multi-component synthesis of indeno[1,2-b]indolone derivatives. The catalyst, composed of spherical nanoparticles with an average diameter of approximately 38 nm, facilitated the reactions with high product yields, remarkable atom economy and excellent recyclability and showing less than a 10 % decrease in yield after five consecutive cycles. The structures and purities of the synthesized derivatives were confirmed using conventional methods and advanced techniques, including 2D NMR and mass spectrometry. To theoretically evaluate the bioactive potential of the compounds, molecular docking studies were conducted to assess their interactions with protein 3C13, a well-studied therapeutic target associated with breast cancer. The results indicated that compound 4 g forms stable and effective interactions with this protein and can inhibit its enzymatic activity. Finally, DFT-based theoretical calculations using the PBE functional with Grimme's dispersion corrections provided complementary insights into the electronic structure and reactivity of the compounds, corroborating the other findings.