1,2,5-三苯基吡咯的合成及其聚集程度对发光强度的影响

Synthesis of 1,2,5-Triphenyl-Pyrrole and Effect of Its Aggregation Degree on Photoluminescence Intensity

采用Schulte-Reisch方法,在氯化亚铜催化下,由1,4-二苯基丁二炔与苯胺反应成功制备了1,2,5-三苯基吡咯(TPP)。通过将溶液反应改进为本体反应,不仅提高了收率,而且降低了反应温度,缩短了反应时间。当水的含量在THF-水混合溶剂中低于60%时,因TPP没有产生聚集,其荧光强度基本没有发生变化;但水含量增加到70%时,因聚集紧密程度较低,π—π堆积作用诱发非辐射能量转移,使荧光强度被猝灭;而当水的含量超过80%以上时,TPP呈现高紧密聚集,使分子内旋转受到限制,降低了非辐射能量转移,使发光得到增强。由于乙腈与TPP之间所形成的较强电荷转移相互作用影响了聚集紧密程度,没有呈现高聚集诱导发光增强性质。

1,2,5-triphenylpyrrole （TPP） was firstly prepared by the Schulte-Reisch reaction of 1,4-diphenylbuta-1,3-diyne with aniline catalyzed by copper chloride. Compared to solution reaction in DMF as solvent, the bulk reaction modified in this paper not only increased the yield and reduced the reaction temperature, but also shortend the reaction time. The π-π stacking inter action and the restriction of intramolecular rotation are were involved at the same time when TPP was aggregated in the THF-- water mixtures. When the water volume fraction was under 60 %, the PL intensity of TPP was independent on the water fraction in THF：water mixture. When the water fraction was added to 70%, which induced the non-tight aggregation of TPP, the strong π-π stacking interaction toned the nonradiative deactivation process and led to quenching the fluorescence of TPP; if the water fraction was further increased to 80%, which induced the tight aggregation of TPP, the restriction of intramolecular rotation was, however, preponderant over π-π stacking interaction. Thus the nonradiative channel was blocked and the photolumineseence intensity of TPP was enhanced. The compact degree of aggregation was influenced by aeetonitrile solvent due to the charge transfer interaction between TPP and acetonitrile. The aggregation-induced emission enhancement of TPP in THF-water mixture disappeared in acetonitrile-water mixture.