engleski

Nonaqueous Route to a Nanocrystalline Metal-Organic Framework VO(C6H5COO)2

Metal–organic frameworks (MOFs) based on transition metal elements are an important family of materials as they provide an opportunity to control the structure dimensionality and, as a consequence, their related properties, such as magnetic ones. In addition, MOFs are also of interest for applications related to their ability to adsorb a wide range of molecules (heterogeneous catalysis) due to their porous structures. In this project, the reaction between VO(OiPr)3, benzoic acid and toluene under solvothermal conditions lead to the synthesis of a new vanadium oxobenzoate [VO(C6H5COO)2]. The compound crystallizes in the monoclinic system with a = 20.6593(7) Å, b = 6.8033(2) Å, c = 9.9598(3) Å, β = 92.15°, space group C2, and Z = 4. The crystal structure has been solved from synchrotron X-ray powder diffraction data using a direct space global optimization technique (program FOX) and refined by the constrained Rietveld method. In addition, a geometry optimization has been performed using the VASP code. We will show how the combination of these three techniques allows solving the structure of this new phase, also if the XRD pattern was poorly resolved. The resulting structure consist of chains, based on corner-sharing VO6 octahedra, separated from each other by the organic part, composed of benzoate moieties. Finally, the electronic and magnetic structures of this new phase will be discussed based on DC magnetization, EPR measurements and DFT calculations.

hybrid; nanocrystalline; characterization

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