The synthesis, structural and mesomorphic properties of five tetrabenzopentaphene derivatives are presented. All the compounds exhibit columnar mesophases which have been characterized by optical microscopy, differential scanning calorimetry and X-ray diffraction. The thermogravimetric analysis of the ester derivatives reveals that they suffer a decomposition process to the anhydride derivative at temperatures above 200 °C. The influence of the length of the terminal alkyl chains on the mesomorphic behaviour of the compounds has been studied. The structural characterization of the compounds has been completed with the study of their aggregation in solution by means of NMR. The fluorescent properties of the compounds are reported as well as a preliminary study of the photoconductivity of one of them.
本文介绍了五种四苯并五并噻吩衍生物的合成、结构和介观性质。所有化合物都呈现柱状介相,并通过光学显微镜、差示扫描量热法和 X 射线衍射法对其进行了表征。酯类衍生物的热重分析表明,在温度高于 200 °C 时,它们会分解为酸酐衍生物。研究了末端烷基链的长度对化合物介形行为的影响。通过核磁共振研究了这些化合物在溶液中的聚集情况,从而完成了对其结构特征的描述。报告还介绍了这些化合物的荧光特性,以及对其中一种化合物的光电导性进行的初步研究。
Synthesis of Extended Triphenylenes by Palladium-Catalyzed [2+2+2] Cycloaddition of Triphenylynes
The synthesis of ortho-(trimethylsilyl)triphenylenyl triflates 7 is described. Fluoride-induced decomposition of these triflates leads to the generation of didehydrotriphenylenes (triphenylynes) 6. These arynes undergo [4+2] cycloadditions with dienes to afford the corresponding Diels-Alder adducts or palladium-catalyzed formal [2+2+2] cycloadditions to afford extendedtriphenylenes.