Synthesis of Three New Fluorinated Hybrid Inorganic-Organic Materials

Hybrid inorganic-organic frameworks have received considerable attention recently because of their wide range of applications including catalysis, ion exchange, separations, and perhaps most notably gas storage. Our research involves synthesizing nanoporous hybrid materials for hydrogen storage applications, specifically hybrids containing fluorinated or partially fluorinated channels. Theoretical calculations performed on fluorinated analogs of hybrids we have previously synthesized have indicated that these materials adsorb hydrogen more strongly at low pressures than their non-fluorinated counterparts. We present three new hybrids containing fluorinated carboxylates: Zn5 (C4F4O4)2 (C2H2N3)6 (H2O) 3 · H2O (1), Co(C8F4O4)(C10H8N2)(H2O) 2 (2), and Mn(C8F4O4)(C10H8N2)(H2O) (3). Compound 1 is a three-dimensional coordination polymer containing 1,2,4-triazolate and tetrafluorosuccinate anions. Structure 2 is a two-dimensional layered phase containing 4,4'-bipyridine and tetrafluoroterephthalate ligands. The most structurally interesting phase, 3, forms from the reaction of Mn2+ ions with 2,2'-bipyridine and tetrafluoroterephthalic acid and contains dimers of edge-sharing MnN2O4 octahedra connected through the fluorinated terephthalate units. These are some of the first examples of hybrid phases containing perfluorinated carboxylate ligands. The structures and properties of these materials and their potential applications in gas storage will be presented.