Solid Phase Morphological Diversity of a Rare Vanadium Cubane (V₄O₁₆) Based Metal Organic Framework

Abstract

A Cu(II) connected V₄O₁₆-cubane based metal organic framework, Cu₂(phen)2(V4O8)(PO4)4 [Cu₂V₄O₁₆-2D] was synthesized under hydrothermal conditions. This is the first example of transition metal connected V₄O₁₆-cubane based MOF. X-ray single crystal data shows the alternate arrangement V₄O₁₆-cubane and Cu(phen)(O)3 square pyramidal unit in two dimensions. These two-dimensional sheets are stacked on top of each other to form a three-dimensional architecture. Cu₂V₄O₁₆-2D shows two types of solid state morphologies of the same phase, which was confirmed by scanning electron microscopy. It is noteworthy that this type of morphological difference of the solid phase in an extended metal–organic hybrid material is rare and has not been perceived in the polyoxovanadate based MOFs literature. Cu₂V₄O₁₆-2D was further characterized by powder X-ray diffraction (PXRD), thermal gravimetric analysis (TGA), IR-spectroscopy, scanning electron microscopy (SEM), and elemental analysis. We also studied the static magnetic and gas adsorption properties for Cu₂V₄O₁₆-2D.