Synthesis, structure determination and characterization of APDAB200, a newaluminophosphate prepared with 1,4-diaminobutane

The title compound (C4H14N2)[Al4P4O17] has been synthesized hydrothermally with 1,4-diaminobutane as the structure-directing agent, and its structure has been solved from X-ray powder diffraction data. The compound crystalliz es in the monoclinic space group P2(1)/c (No. 14) with a = 19.6721(4) Angst rom, b = 9.2201(2) Angstrom, c = 9.7478(2) Angstrom and beta = 95.60 degree s. The structure contains two types of layers (layers A and B). Layer A con tains one tetrahedrally coordinated aluminum and one trigonal bipyramidal [ AlO5] unit connected to five different phosphorus atoms. In layer B, two [A lO5] trigonal bipyramids share an edge to form the Al2O8 double pyramid uni t. Each oxygen atom of the shared edge also forms a bridge to another trigo nal bipyramidal unit. Such aluminate tetramer was previously observed in Al PO4-12 and in the layered aluminophosphates UiO-13 and UiO-14. Stacking of layers A and B along the a-axis generates a three-dimensional network with 10 ring zigzag channels (4.2 x 6.0 Angstrom) along the c-axis and eight rin g zigzag channels along the a-axis. These channels intersect to form a two- dimensional channel system. The framework is closely related to that of AlP O4-12 which is made up of layers B connected to AlPO4 sheets containing onl y tetrahedral aluminum. The compound was characterized by MAS, Al-27 2D-5Q MAS and Al-27-P-31 CP/MAS correlation NMR spectroscopy. All Al-27 as well a s P-31 NMR signals have been assigned to the different crystallographic sit es of the structure. (C) 2000 Elsevier Science B.V. All rights reserved.