Photosciences and Photonics Section, Chemical Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology (NIIST) and Network of Institutes for Solar Energy, CSIR, Trivandrum, India.
J Phys Chem B. 2012 Nov 1;116(43):13071-80. doi: 10.1021/jp305349h. Epub 2012 Oct 18.
Star-shaped molecules consisting of a 1,3,4-oxadiazole core derivatized with alkoxy-substituted phenyl ethynylenes, FD12 (dodecyl) and FD16 (hexadecyl) were synthesized. These molecules exhibited enantiotropic columnar mesophases over a wide temperature range, with the liquid crystalline phases exhibiting strong blue fluorescence. On cooling, FD12 transformed into a transparent glass at room temperature wherein the liquid crystalline texture was retained. The glassy film remained stable over a period of one year and exhibited blue luminescence with an absolute quantum yield of 26%. The oxadiazole derivatives formed stable luminescent gels in decane and study of their morphology by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated formation of interlocked network of self-assembled fibers. X-ray diffraction (XRD) analysis of the xerogel of these derivatives indicated oblique columnar ordering of the molecules within the fibers. The length of the alkyl substituent was observed to have a significant effect on the absorption and fluorescence properties of the gels, which was attributable to the role of the alkyl substituents in controlling the nature of the molecular packing within the self -assembled fibers of the gels.
星形分子由 1,3,4-恶二唑核心衍生而来，其中芳基乙炔基被烷氧基取代，分别是 FD12（十二烷基）和 FD16（十六烷基）。这些分子在很宽的温度范围内表现出各向异性柱状介晶相，液晶相表现出强烈的蓝色荧光。FD12 在冷却时在室温下转变为透明玻璃，保留了液晶织构。玻璃态薄膜在一年的时间内保持稳定，并表现出具有 26%的绝对量子产率的蓝色发光。恶二唑衍生物在癸烷中形成稳定的发光凝胶，通过扫描电子显微镜 (SEM) 和透射电子显微镜 (TEM) 研究其形态表明形成了自组装纤维的互锁网络。这些衍生物的干凝胶的 X 射线衍射 (XRD) 分析表明分子在纤维内呈斜柱状排列。观察到烷基取代基的长度对凝胶的吸收和荧光性质有显著影响，这归因于烷基取代基在控制凝胶自组装纤维内的分子堆积性质方面的作用。
