Juglone-derived Eu(III) and Gd(III) complexes: synthesis, characterization, photoluminescence properties, cytotoxic activities, thermal analyses, DFT perspectives, and VEGFR2 docking simulation

Two new seven coordinate Eu(III) and Gd(III) complexes have been synthesized from 5-hydroxy-1,4-naphthoquinone (HNQ). Elemental analysis, UV-Vis, IR, MALDI-TOF, and TGA have all been used to explore the structural characterization of these compounds. Moreover, the cytotoxic activities and photoluminescent characteristics of the synthesized Eu(III) and Gd(III) complexes were investigated. Complexes excited at 275 nm displayed emission bands from 310 to 600 nm. The complexes have metal-based f-f transitions. Also, the cytotoxic effects of ligands and complexes on HTB-54 and A549, two non-small cell lung cancer cells, were examined in this work. For the lung cancer cell lines A549 and HTB-54, the ligand’s IC50 values have been found to be 23.40 and 9.05 μM, respectively. The optimized geometries of the ligand Juglone and its Eu(III) and Gd(III) complexes were determined using DFT with the B3LYP hybrid functional. Several computational analyses were performed, including molecular electrostatic potential (MEP) mapping, HOMO-LUMO molecular orbital analysis, and quantum chemical reactivity descriptors. These studies provided insights into the reactive sites, chemical reactivity, biological activity, and overall stability of the title compounds. Furthermore, to validate the experimental findings and gain deeper insights into the interactions, the anticancer activity of the synthesized compounds was evaluated through molecular docking simulations.