Syntheses and characterizations of heteroatom-containing open-framework aluminophosphates

Two heteroatom-containing open-framework aluminophosphates, (C3H4N2)(FeAl3P4O16)-Fe-2 and (C3H4N2)(2)CrAl3P4O16 (denoted as MAPO-CJ50, M = Fe, Cr), have been synthesized by using imidazole as the template under solvothermal conditions. The structure of FeAPO-CJ50 is determined by single-crystal X-ray diffraction, and its analogous structure CrAPO-CJ50 is identified by powder X-ray diffraction. The 3-dimensional framework of MAPO-CJ50, constructed by MO4N2 octahedra, AlO4 tetrahedra, and PO4 tetrahedra, contains interconnecting 10- and 8-ring channels. Imidazole molecules are coordinated with framework M3+ ions and interact with each other through pi-pi stacking interactions in the channels. These two compounds show photoluminescent properties due to ligand-to-metal charge transfer. Magnetic measurements reveal that there are antiferromagnetic interactions between M3+ ions in the frameworks of FeAPO-CJ50 and CrAPO-CJ50.