Effect of auxiliary ligand on the crystalline architectures of copper(II)-sparfloxacin complexes via coordinative and supramolecular interactions

Reactions of sparfloxacin (Hsf) with Cu(II), in the absence or presence of auxiliary ligands (bpy, 2,2′-bipyridine; dmbpy, 4,4′-dimethyl-2,2′-bipyridine) under similar conditions, afforded three coordination complexes, [Cu(Hsf)2(ClO4)](ClO4)(CH3OH)2(H2O)3.75 (1), [Cu(Hsf)(bpy)(ClO4)](ClO4)(H2O) (2), and [Cu2(Hsf)2(dmbpy)2(ClO4)3](ClO4)(C2H5OH)3(H2O)0.75 (3). All three complexes have been structurally characterized by single-crystal X-ray diffraction. In their crystal structures, distinct extended metallosupramolecular architectures, specifically 3D (for 1), 2D (for 2), and 2D + 1D (for 3), are constructed with the aid of secondary interactions involving H-bonding and aromatic stacking.