Ionothermal Synthesis and Characterization of a Layered Propylene Diammonium Gallium Phosphate, (C₃H₁₂N₂)₆[Ga₁₂P₁₆O₆₄] · 4.3 H₂O

Abstract

Abstract A new propylene‐1,3‐diammonium gallium phosphate of composition (C 3 H 12 N 2 ) 6 [Ga 12 P 16 O 64 ] · 4.3 H 2 O (LUH‐1) was obtained by ionothermal synthesis using a deep‐eutectic solvent (DES) composed of choline chloride and tetrahydro‐2‐pyrimidione as reaction medium. The structure‐directing agent propylene‐1,3‐diammonium was generated in situ by the thermally induced decomposition of the amide component of the DES. Single‐crystal X‐ray structure analysis revealed that LUH‐1 is built from macroanionic tetrahedral gallium phosphate layers and layers of interlamellar propylene‐1,3‐diammonium cations, with the latter exhibiting two‐fold disorder. The one‐dimensional 12‐membered ring channel system is occupied by highly disordered water molecules. As indicated by thermogravimetry and powder X‐ray diffraction the water molecules can be desorbed from LUH‐1 at ca. 100 °C with retention of the layered inorganic‐organic hybrid structure. Crystal data for LUH‐1: Trigonal system, space group $P{\bar 3}$ c 1 (No. 165), Z = 1, a = 12.905(4), c = 18.317(8) Å, T = 297 K.