Ishimaru Shin'ichi, Saito Kazuya, Ikeuchi Satoaki, Massalska-Arodz Maria, Witko Waclaw
Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
J Phys Chem B. 2005 May 26;109(20):10020-4. doi: 10.1021/jp0501244.
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.
通过核磁共振氢谱（¹H NMR）和绝热量热法，对标题化合物4-丁基-4'-异硫氰基-1,1'-联苯（4TCB）在软晶体近晶E（SmE）相中的分子动力学及由此产生的无序性进行了详细研究。经过长时间的两步退火，首次在环境压力下实现了4TCB的有序晶相，并将其用作实验结果分析的参考状态。通过对¹H NMR T₁的分析，在SmE相中确定了四种运动模式。残余熵测定为约6 J K⁻¹ mol⁻¹。这个量级意味着，在高温下SmE相中的大部分无序性在冷却时被消除，除了棒状4TCB分子的头对尾无序性。在375 K以下列出了标准热力学函数。
