New organically templated gallium oxalate-phosphate structures based on Ga4(PO4)4(C2O4) building unit

Five organic-inorganic hybrid gallium oxalate-phosphates, [Ga-2(PO4)(2)(H2O)(C2O4)(0.5)](C3N2H12)(0.5)(H2O) (1), [Ga-2(PO4)(2)(C2O4)(0.5)] (C2N2H10)(0.5)(H2O) (2), [Ga-2(PO4)(2)(C2O4)(0.5)](C3N2H12)(0.5) (3), [Ga-2(PO4)(2)(H2PO4)(0.5)(C2O4)(0.5)](C4N3H16)(0.5) (H2O)(1.5) (4) and [Ga-2.5(PO4)(2.5) (H2O)(1.5)(C2O4)(0.5)](C4N3H15)(0.5) (5), have been synthesized by using 1,3-diaminopropane, ethylenediamine and diethylene triamine as structure-directing agents under hydrothemial condition. The structures of 1-5 are based on Ga-4(PO4)(4)(C2O4) building unit made up from Ga2O8(C2O4) oxalate-bridging dimer and alternating PO4 and GaO4 tetrahedral units. Compound 1 is layered structure where the building units link together in the same orientation. Corner sharing of these similar layers result in three-dimensional (3-D) structure 2. However, in compound 3, the building units arrange in a wave-like way to generate two types of eight member ring (8MR) channels. Both 4 and 5 contain the layers where the building units have an opposite orientation. Those layers are linked by H2PO4 group and Ga(PO4)(H2O)(3) cluster, respectively, to form 3-D frameworks with 12MR large pore channels. Compounds 2-5 exhibit intersecting 3-D channels where the protoned amines are located. (C) 2006 Elsevier Inc. All rights reserved.