EPR Study on the Intercalation of Azoles into Transition Metal Oxides

Four azoles of different chemical structure were intercalated into MoO3, V2O5, and WO3 oxides synthetized via polycondensation of corresponding oxo-acids under the solvothermal conditions. Structural and morphology peculiarities of these hybrid materials were characterized using X-ray and neutron diffraction, electron microscopy and EPR spectroscopy. The EPR measurements provided the evidence that azole molecules coordinate monomers and oligomers of molybdic, tungstic and vanadic acids during the course of solvothermal synthesis of azole-oxide hybrid structures. This coordination is accompanied with reorganization of growing oxide frame leading to the unprecedently high azole loading. As the result, the azole-intercalated layered oxides with high concentration of ordered paramagnetic centers are formed.