Molecular Gyrotops with a Five-Membered Heteroaromatic Ring: Synthesis, Temperature-Dependent Orientation of Dipolar Rotors inside the Crystal, and its Birefringence Change
Molecular Gyrotops with a Five-Membered Heteroaromatic Ring: Synthesis, Temperature-Dependent Orientation of Dipolar Rotors inside the Crystal, and its Birefringence Change
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DOI：
10.1021/acs.cgd.6b00508
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发表时间：
2016-08-01
影响因子：
3.8
通讯作者：
Setaka, Wataru
中科院分区：
文献类型：
--
作者：
Masuda, Toshiyuki;Arase, Junko;Setaka, Wataru
三维阵列的偶极转子被构造为单晶的分子陀螺，这是一个大笼分子与桥接的偶极转子。在这项研究中，我们合成了一种新的分子gyrotops与五元杂环，即，呋喃-二基（1）、噻吩-二基（2）和硒代苯-二基（3），并研究了晶体内偶极转子的温度依赖性取向和旋转。不幸的是，呋喃衍生物1没有结晶;然而，另一种分子gyrotops，即，图2和图3示出了偶极转子的三维阵列。在2和3中观察到晶体内部偶极转子取向的热有序-无序转变，其中硒代衍生物3的转变温度低于噻吩衍生物2的转变温度。这可能归因于分子结构的细微差异，例如，对应于旋转轴的两个Si-C（芳基）键之间的交叉角。根据晶体结构的热变化，通过分析晶体的双折射，观察到单晶的光学性质随温度的变化。
Three-dimensional arrays of dipolar rotors were constructed as single crystals of molecular gyrotops, which are macrocage molecules with a bridged dipolar rotor. In this study, we synthesized novel molecular gyrotops with a five-membered heteroring, i.e., furan-diyl (1), thiophene-diyl (2), and selenophene-diyl (3), and investigated the temperature-dependent orientation and rotation of the dipolar rotors inside the crystal. Unfortunately, furan derivative 1 did not crystallize; however, crystal structures of the other molecular gyrotops, i.e., 2 and 3, showed three-dimensional arrays of dipolar rotors. Thermal order-disorder transitions of the dipolar rotor orientation inside the crystal were observed in 2 and 3 with the transition temperature in selenophene derivative 3 being lower than that of thiophene derivative 2. This may be ascribed to subtle differences in the molecular structure, e.g., the intersection angle between two Si-C(aryl) bonds corresponding to the rotation axis. In accordance with the thermal change of the crystal structure, temperature-dependent optical properties of a single crystal were observed by analysis of birefringence of the crystal.