Crystal Structure and Supramolecular Assembly of a Novel Copper(II) Cyclam 3,5‐Dinitrobenzoate Complex

ABSTRACT A novel copper(II) complex, Cu(mac)(dinit) 2 , where “mac” denotes a macrocycle 1,4,8,11‐tetraazacyclotetradecane (cyclam), and “dinit” denotes 3,5‐dinitro benzoate (3,5‐(NO 2 ) 2 C 6 H 3 COO), has been synthesized and structurally characterized by single‐crystal x‐ray diffraction. The complex exhibits a distorted octahedral geometry in which the Cu(II) ion is located on an inversion center and is equatorially coordinated by four nitrogen atoms of the cyclam macrocycle, while the axial positions are occupied by two monodentate carboxylate oxygen atoms from the 3,5‐dinitrobenzoate ligands. Notably, no coordinated water molecules are present either within the coordination sphere or in the crystal lattice. The axial Cu─O bond distances (2.465 Å) are significantly shorter than those reported for related hydrated analogues, indicating stronger axial coordination in the present system. The crystal packing is further stabilized by intra‐ and intermolecular N─H···O hydrogen‐bonding interactions, which generate a two‐dimensional layered supramolecular network. This structural arrangement highlights the role of electron‐deficient aromatic carboxylate ligands in modulating both the coordination environment and the supramolecular organization of macrocyclic Cu(II) complexes. The structural conclusions are supported by complementary elemental analysis, FT‐IR and UV–visible spectroscopy, thermogravimetric analysis, magnetic susceptibility measurements, and ground‐state density functional theory (DFT) calculations, which together provide a comprehensive understanding of the physicochemical properties of the complex.