Wydział Chemii

Magdalena Rok

Anna Piecha-Bisiorek

Przemysław Szklarz

Grażyna Bator

Lucjan Sobczyk

2015

Chemical Physics

452

53-60

10.1016/j.chemphys.2015.02.018

Naukowa

Angielski

Artykuł

The electric response was analyzed in the vicinity of the structural phase transition at 412 K in the single crystals of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (chloranilic acid, CLA) with 4,4′-di-t-butyl-2,2′-bipyridyl (dtBBP). The dielectric permittivity of the complex measured along the b direction between 300 and 440 K and at frequencies ranging from 500 Hz to 2 MHz indicates two phenomena. At low frequencies, dielectric losses are ascribed to the electric conductivity of the crystal, while at high frequencies, to the dielectric relaxation described by means of the Cole–Cole relationship. The parameters of the dielectric response: the relaxation time, τ, the dielectric increment, ε_ο − ε_∞, and the distribution parameter of the relaxation time, α, were estimated and analyzed. The low-temperature structure of the crystals indicates the antiferroelectric arrangement of the supramolecular hydrogen bonds. The dielectric results also presented for the deuterated crystals of dtBBP·CLA proved that the dynamics of protons in the hydrogen bonds are responsible for the mechanism of phase transition.

phase transition, antiferroelectric, supramolecular complex, semiconducing

http://dx.doi.org/10.1016/j.chemphys.2015.02.018

http://www.elsevier.com