Molecular dynamics and residual entropy in the soft crystal, SmE phase, of 4-butyl-4'-isothiocyano-1,1'-biphenyl

Shin'ichi Ishimaru; Kazuya Saito; Satoaki Ikeuchi; Maria Massalska-Arodz; Waclaw Witko

doi:10.1021/jp0501244

Molecular dynamics and residual entropy in the soft crystal, SmE phase, of 4-butyl-4'-isothiocyano-1,1'-biphenyl

J Phys Chem B. 2005 May 26;109(20):10020-4. doi: 10.1021/jp0501244.

Authors

Shin'ichi Ishimaru¹, Kazuya Saito, Satoaki Ikeuchi, Maria Massalska-Arodz, Waclaw Witko

Affiliation

¹ Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.

PMID: 16852212
DOI: 10.1021/jp0501244

Abstract

Molecular dynamics and resulting disorder in the soft crystal, smectic E (SmE) phase, were studied in detail for the title compound, 4-butyl-4'-isothiocyano-1,1'-biphenyl (4TCB), by (1)H NMR spectroscopy and adiabatic calorimetry. The ordered crystal phase of 4TCB was realized for the first time under ambient pressure after long two-step annealing and used as the reference state in the analysis of the experimental results. Four motional modes were identified in the SmE phase through the analysis of the (1)H NMR T(1). The residual entropy was determined as ca. 6 J K(-1) mol(-1). This magnitude implies that most of the disorder in the SmE phase at high temperatures is removed on cooling except for the head-to-tail disorder of the rod-shaped 4TCB molecule. Standard thermodynamic functions are tabulated below 375 K.