Syntheses, Structural Characterization, Optical and Magnetic Properties of a New Polyoxovanadate-Based Metal-Organic Polyhedron

A new polyoxovanadate-based metal-organic polyhedron, termed V-MOP-19, constructed from pentanuclear {V5O9Cl} clusters and 1,4-naphthalenedicarboxylic acid linkers, was successfully fabricated via the solvothermal method. Structural analysis revealed that V-MOP-19 adopts the cubic symmetry featured with an octahedral pore cage of 15.7 angstrom. Full characterization of V-MOP-19 was measured by Fourier transform infrared (FT-IR), Raman spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), transmission electron microscopy (TEM), thermogravimetric and differential scanning calorimetry analysis (TGA-DSC), N-2 sorption isotherm and elemental analysis (EA). The band gap energy of V-MOP-19, measured by UV-Vis diffuse reflectance spectroscopy (UV-Vis/DRS), is determined to be 2.38 eV. Moreover, the cyclic voltammetry investigation confirms a high correspondence of the band gap value (2.41 eV) with the mentioned UV-Vis/DRS study. In particular, V-MOP-19 exhibits a unique magnetic property with remarkable coercivity and remanent magnetization value. These findings demonstrate that V-MOP-19 could be used as a potential candidate in further photocatalytic and magnetic investigations.