Structure Determination of Novel Aluminophosphate Synthesized Using Diethylamine as Structure Directing Agents

Three-dimensional crystal structure of novel aluminophosphate PST-5 solved using a powder charge flipping method

“…Aluminophosphates were synthesized as described below. 10,12 H 3 PO 4 (3.84 g, 85%, Daejung) was dissolved in doubly distilled water (5.63 g) and the solution was stirred for 1 h. Aluminum isopropoxide (AIP, 6.95 g, 98%, Aldrich) was slowly added dropwise to doubly distilled water (5.64 g) with vigorous stirring to achieve hydrolysis. The phosphoric acid solution was then combined with the hydrolyzed aluminum hydroxide solution with vigorous stirring and the mixture was stirred for further 1 h. Diethylamine (DEA, 2.45 g, 99.5%, Aldrich) was added dropwise to the mixture with vigorous stirring.…”

“…Diffraction patterns obtained were indexed using the DIC-VOL06 program implemented in the FullProf program suite. 10 The initial structure of DEA in the framework was obtained by the MM2 method implemented in ChemBio3D. 25 Subsequently the parallel tempering algorithm implemented in the Free Objects for Crystallography program was applied to determine the framework structure containing DEA.…”

“…9 Furthermore, the presence of amorphous phases in the polycrystalline material hampers accurate structure determination. 10 Aluminophosphates are usually unstable or are transformed into other topological structures under heat treatment in the presence of water; they are indeed prone to decompose or give way when irradiated by an electron beam. 11 Therefore, it is extremely difficult to readily determine the structures of aluminophosphates.…”

“…13 This synthetic approach, using a low-cost amine, is intriguing because the hydrolysis of the aluminum precursor, and solvent evaporation prior to hydrothermal treatment, can produce various novel aluminophosphates. 10,12 Recently, the novel aluminophosphate obtained from a controlled hydrothermal synthesis using DEA as the structuredirecting agent was also found to have a tetragonal structure in which the lattice parameters were a ¼ 14.44938 (18)Å and c ¼ 18.27743(18)Å. 8 The corresponding novel structure was determined unambiguously using the powder charge ipping (pCF) method, 14,15 and was designated as "CNU-2".…”