The structure-directing effect of n-propylamine in the crystallization of open-framework aluminophosphates

Using n-propylamine as a template, deioned water and secondary-butanol (butan-2-ol) as solvents, a three-dimensional (3D) open-framework aluminophosphate [C3NH10]·[HAl3P3O13] (1) and a two-dimensional layered aluminophosphate [C3NH10]3·[Al3P4O16] (2) were crystallized from the initial mixtures with compositions of Al2O3: 2.4 P2O5: 5.0 n-propylamine: 100 H2O/butan-2-ol, respectively. They are characterized by X-ray powder diffraction (XRD), thermogravimetric (TG), and elemental (CHN) analyses and structurally determined by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the monoclinic space group P21/c with a = 0.85831(13) nm, b = 1.7677(3) nm, c = 1.04353(12) nm, β = 123.887(9)°, and V = 1.3143(3) nm3. Compound 2 crystallizes in the monoclinic space group P21/c with a = 1.1313(2) nm, b = 1.4874(3) nm, c = 1.8020(6) nm, β = 125.07(2)°, and V = 2.4817(11) nm3. The results show that the properties of solvent have a significant influence on the structure-directing effect of n-propylamine in the crystallization of the open-framework aluminophosphates.