Phase transitions in two organic salts based on 1,5-naphthalenedisulfonate

Two phase transition compounds, diethylammonium 1,5-naphthalenedisulfonate (1) and cyclohexylammonium 1,5-naphthalenedisulfonate (2), were screened from a series of organic salts based on 1,5-naphthalenedisulfonate. The phase transition behaviors were studied by differential scanning calorimetry, single-crystal X-ray analysis and dielectric measurements. Compounds 1 and 2 undergo phase transitions at about 202 and 148 K, respectively, accompanied by distinct dielectric changes. The origin of the phase transitions was ascribed to motional changes of the cations in the crystal lattices.