Synthesis and crystal structures of four three-dimensional hybrid materials based on polyoxovanadate bridging macrocyclic copper/nickel complexes

In this research, four hybrid materials, namely [Ni(MC)]3[VO3]6·12.25H2O (1), [Cu(MC)]3[VO3]6 (2), [Ni(PC)]3[VO3]6·2H2O (3), and [Cu(PC)]3[VO3]6·2H2O (4) (MC = 1,8-dimethyl-1,3,6,8,10,13-hexaazacyclotetradecane, PC = 1,8-dipropyl-1,3,6,8,10,13-hexaazacyclotetradecane), were obtained by reacting transition metal macrocyclic complexes with NH4VO3. Subsequently, they were characterized by physico-chemical and spectroscopic methods, and X-ray powder diffraction. Single-crystal structure analysis revealed that the Ni(II)/Cu(II) atoms were coordinated by two oxygen atoms from [VO4] tetrahedra and four nitrogen atoms from ligands, thereby forming a six-coordinate octahedral coordination geometry. Six [VO4] tetrahedra form a hexanuclear [V6O18]6− ring by sharing six μ2-oxygen atoms in complexes 1–4. All complexes exhibited similar three-dimensional structures formed by connections of hexanuclear [V6O18]6− rings with their corresponding cationic moieties.