两种新碗形分子的合成及其纤维状晶的研究

Studies on Synthesis of Two Novel Bowl-like Molecules and Their Fibrous Crystals

以香兰素为原料,采用三聚法合成了2种外围脂肪族基团碳数分别为3和5的环三亚藜芦基(cyclotriveratrylene,CTV)系衍生物碗形分子——CTV-3和CTV-5,其中,用先关环后衍生化的合成路线克服了因CTV-5的外围基团太长、分子对称性不好而无法用传统方法合成的难题。产物的化学结构经1H NMR、13CNMR、质谱以及元素分析确认。在偏光显微镜下观察到纤维状晶叠加在碗形分子的向列液晶织构上。纤维状晶是从液晶态冷却时形成并装饰在原液晶织构上的一种结晶形态。通过SEM测定,观察到纤维状晶实际上是由厚度约为100～200nm、宽度为2～5μm的无限长的单层片晶组成的多层片晶,而片晶则是由直径约为100nm的微纤组成的。微纤可以推断是碗形分子柱的束状聚集体。

Two novel bowl-like cyclotriveratrylene （CTV）, i.e. CTV-3 and CTV-5 termed according to the different peripheral groups with carbon number 3 and 5 respectively, were synthesized. CTV-3 was prepared by a the typical trimerization via a muhistep sequence from vanillin, however it remains restricted to the preparation of the CTV-5 with larger peripheral group and less molecular symmetry via this conventional method. In this paper, an alternative synthesis route with first closing ring and then derivatization was designed to prepare CTV-5. The chemical structures of the products were characterized by means of ^1H NMR,^13C NMR, mass spectrometry and element analysis. For the final products CTV-3 and CTV-5, many fibrous crystals were observed under polarized optical microscopy, which crystallized during the cooling from nematic phase, and decorated the so-called liquid crystal grainy texture. By means of scanning electron microscope, it can be observed the fibrous crystals were actually very long multi-layer lamelIae, which consist of single layer lamellae with the thickness of about 100 to 200rim,width of 2 to 5μm and infinite length. The single layer lamellae were further composed of fibrils which diameter was about 100nm. It could be deduced that these fibrils were the aggregates of bowlic molecular columns.