Synthesis and thermal analysis of disubstituted propiolates bearing terphenylene mesogen
作者:Lie Chen、Yiwang Chen、Weihua Zhou、Xiaohui He、Yanlin Song、Zhijie Zhang
DOI:10.1007/s10973-009-0199-9
日期:2010.2
Novel disubstituted propiolates bearing chromophoric terphenylene mesogenic groups, namely, 4′-cyano-4-terphenylyl-2-octynate M(CN) and 4′-methoxyl-4-terphenylyl-2-octynate M(OCH3) are synthesized, where the terphenyl groups are connected to the C≡C through ester linkage directly. Using transition-metal catalysts such as the classical MoCl5- and WCl6-based metathesis catalysts, the polymerization of the M(CN) and M(OCH3) are carried out in a series of different solution, however, did not obtain any products. It suggests that the WCl6- and MoCl5-based catalysts are poisoned by the polar groups, on the other hand, the bulk terphenyl groups and the long alkyl chain around the C≡C bond might inhibit the reaction. M(CN) displays monotropic nematicity, whereas M(OCH3) exhibits enantiotropic nematicity and smecticity (SmAd) with a bilayer arrangement when cooled and heated. Ultraviolet spectroscopy and photoluminescence measurements also show that the terphenyl groups endow disubstituted propiolates with strong UV light absorption and high photoluminescence.
合成了具有色品特苯介质基团的新型二取代丙炔酸酯,分别为4′-氰基-4-特苯基-2-辛酸酯M(CN)和4′-甲氧基-4-特苯基-2-辛酸酯M(OCH3),其中特苯基团通过酯键直接与C≡C连接。通过使用过渡金属催化剂,如经典的基于MoCl5和WCl6的复分解催化剂,在一系列不同的溶液中进行M(CN)和M(OCH3)的聚合实验,然而未能获得任何产物。这表明WCl6和MoCl5基催化剂被极性基团毒化,另一方面,体积较大的特苯基团和C≡C键周围的长烷基链可能抑制了反应。M(CN)显示出单向性向列相,而M(OCH3)在冷却和加热时则表现出对称性向列相和层状相(SmAd),呈双层排列。紫外光谱和光致发光测量结果也表明,特苯基团赋予了二取代丙炔酸酯强烈的紫外光吸收和高光致发光性能。