Novel Organically Templated Mixed-Valent Titanium Phosphates with Open Framework Structures: Hydrothermal Synthesis and Characterization

We have hydrothermally synthesized the first reduced titanium phosphates with open-framework structures. The synthetic approach is quite unusual since elemental titanium is used. The full structural, thermal, magnetic, and spectroscopic characterization of a 1,3-diaminopropanetemplated compound, TiIIITiIV(PO4)(HPO4)2(H2O)2·(NH2CH2CH2CH2NH2)0.5, is presented. The frame of the compound is of the octahedral/tetrahedral type with octahedrally coordinated TiIII and TiIV atoms. The template of 1,3-diaminopropane occupies channels with dimensions that are comparable to those of many zeolites. Magnetic measurements are consistent with one d-electron per formula unit. TGA/DTA and IR data will be reported as well. This compound is most likely the first member of a larger class of reduced titanium phosphates. Some preliminary data suggests that similar reduced titanium phosphates with different templates and structures exist as well. All compounds are blue-purple due to Ti(III).