Synthesis, structural analysis, and docking studies with SARS-CoV-2 of a trinuclear zinc complex with N-phenylanthranilic acid ligands.

The structure of a trinuclear zinc complex, hexakis(μ 2 -2-anilinobenzoato)diaquatrizinc(II), [Zn 2 (C 13 H 10 NO 2 ) 6 (H 2 O) 2 ] or (NPA) 6 Zn 3 (H 2 O) 2 (NPA is 2-anilinobenzoate or N-phenylanthranilate), is reported. The complex crystallizes in the triclinic space group P-1 and the central Zn II atom is located on an inversion center. The NPA ligand is found to coordinate via the carboxylate O atoms with unique C-O bond lengths that support an unequal distribution of resonance over the carboxylate fragment. The axial H 2 O ligands form hydrogen bonds with neighboring molecules that stabilize the supramolecular system in rigid straight chains, with an angle of 180° along the c axis. π stacking is the primary stabilization along the a and b axes, resulting in a highly ordered supramolecular structure. Docking studies show that this unique supramolecular structure of a trinuclear zinc complex has potential for binding to the main protease (M pro ) in SARS-CoV-2 in a different location from Remdesivir, but with a similar binding strength.