作者:Kenneth E. Maly、Caroline Dauphin、James D. Wuest
DOI:10.1039/b610666h
日期:——
Diaminotriazines are known to self-associate in solution, in the solid state, and on surfaces via characteristic hydrogen bonding motifs. Although complementary hydrogen bonding between diaminotriazine derivatives and carboxylic acids has been shown to induce mesomorphic properties, the hydrogen-bonded self-association of diaminotriazines to form liquid crystalline phases has not been reported. Here, we describe the synthesis and mesophase characterization of biphenyldiaminotriazines bearing one alkoxy side-chain (compound 3) or two alkoxy side-chains (compound 2). Although compound 3 does not show any mesomorphism, derivatives of compound 2 exhibit thermotropic columnar mesophases as shown by polarized optical microscopy, differential scanning calorimetry, and variable-temperature X-ray powder diffraction. The results are consistent with self-assembly of a hexameric hydrogen-bonded rosette that can stack to form columnar mesophases, suggesting that the association of diaminotriazines by hydrogen bonding can play an important role in directing molecular organization in liquid crystalline phases.
已知二氨基三嗪通过特征性氢键结构在溶液、固态和表面上能够自组装。虽然二氨基三嗪衍生物和羧酸之间的互补氢键已被证实可以诱导介晶性质,但二氨基三嗪通过氢键自组装形成液晶相尚未见报道。本文描述了带有一个烷氧基侧链(化合物3)或两个烷氧基侧链(化合物2)的联苯二氨基三嗪的合成和介晶相表征。虽然化合物3不显示任何介晶性,但化合物2的衍生物表现出热致柱状介晶相,这通过偏光显微镜、差示扫描量热法和可变温X射线粉末衍射得到证实。结果表明,六聚体氢键玫瑰环可以堆积形成柱状介晶相,说明二氨基三嗪通过氢键结合在液晶相分子组织中起重要作用。