Role of crystallization water molecules on hydrogen-bonded structures and dielectric phase transitions in amino trimethylene phosphonic acid-based crystals

Three hydrogen-bonded organic salts (HTBA)2(H4ATMP)·(H2O)3 (1), (HTBA)6(H3O)(H2.5ATMP)2·(H2O)2 (2) and (HTBA)6(H3ATMP)2·H2O (3) were synthesized by combining different molar ratios of amino trimethylene phosphonic acid (H6ATMP) and tert-butylamine (TBA). There are three-dimensional hydrogen-bonded networks in 1–3. The crystallization water molecules that are loosely trapped in the supramolecular hydrogen-bonded networks in 1 and 2 undergo order–disorder transitions whose dynamic changes are likely to be responsible for dielectric transitions and relaxations.