Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5377337 | Chemical Physics | 2006 | 7 Pages |
Abstract
Temperature and frequency dependence of the dielectric permittivity of a mono-tetramethylammonium (TMA) salt of a novel squaric acid derivative, o-phenylenebis(squaric acid) (o-PBSQ), was investigated by ac dielectric measurement. The origin of the anomaly observed around 300Â K and 100Â K was discussed based on the crystal structure analysis at 350, 179, and 112Â K. The space group changes from P42/n (350Â K) to P21 (112Â K) through P21/n (179Â K); o-PBSQ forms a dimer through two ionic hydrogen bonds in three crystal structures. The dielectric behavior around 300Â K is originated from the ion polarization because the structural phase transition around 300Â K is characterized by the translational shifts of the o-PBSQ dimer and TMA. The anomaly around 100Â K may be derived from the proton transfer along the two ionic hydrogen bonds of the o-PBSQ dimer because the transition temperature exhibited a distinct deuteration effect.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Shigefumi Yamamura, Yoko Sugawara, Hiroshi Terao, Michio M. Matsushita, Tadashi Sugawara,