Synthesis, structure, Hirshfeld surface analysis, and molecular docking studies of the Cu(II) complex with 3-nitro-4-aminobenzoic acid

The first representative of 3-nitro-4-aminobenzoic acid (3N-4ABA) monoligand metal complexes has been obtained on an example of the Cu(II) complex. The structure of the compound was studied using element analysis, IR- and UV-spectroscopy, and Hirshfeld surface analysis while bioactivity is assessed by molecular docking. Cu(II) ions coordinate two 3N-4ABA molecules bidentately through the oxygen atoms of the carboxylate group, and there are water molecules in the other two positions of the coordination sphere, i.e., all coordinated atoms are only oxygen ones which leads to the formation of the essentially distorted octahedron due to the Janh-Teller effect. Moreover, there is one water molecule in the outer sphere, making this compound a crystal hydrate with the formula of [Cu(3N-4ABA)₂(H₂O)₂]·H₂O. The complicated system of the intermolecular H-bonds and π···π staking interactions incorporate complex molecules into the 3D network. In silico studies of the 3N-4ABA ligand and Cu-complex attested that antimicrobial and antitumor activities indicate a higher affinity of the complex for some key binding sites especially relatively to S. aureus and KDM4 with binding energies of − 9.6 and − 9.2 kcal/mol, respectively.