Hydrothermal synthesis and characterization of two novel tungstovanadophosphate derivatives

摘要

Two novel tungstovanadophosphate derivatives, namely [Fe(phen)3]2[PW2~(VI)V~VV_5~(IV)O_(42)] · H2O (1) and [Fe(phen)3]2[PW9V3O_(40)] (2), were synthesized under hydrothermal conditions, and characterized by elemental analysis, IR, ESR, XPS, TGA, and single-crystal X-ray diffraction analysis. The crystal structure analyses reveal that the 'mixed-addenda' Keggin polyoxoanion in 1 is decorated with VO~(2+) units, such that four V atoms are disordered over eight metal sites; the anion in compound 2 has a typical Keggin structure with three V atoms disordered over 12 metal sites. The two compounds are ionic crystals with slightly different packing modes for the polyoxoanions and [Fe(phen)3]~(3+) cations, π-π stacking interactions between phen molecules, weak hydrogen bonding interactions between phen ligands and polyoxoanions, and electrostatic forces lead to an extended 3D supramolecular framework.