performed. The absorption spectra are quite similar with the maxima in the range 572 nm (aryl = phenyl)–643 nm (aryl = 2-thienyl) in accordance with time dependent DFT calculations of excitation energies. No fluorescence was observed in solution, while all compounds fluoresce in low temperature solvent glass (77 K) and a weak solid-state fluorescence of phenyl and 2-naphthyl derivatives in red/IR region was
通过氧化二聚反应,合成了5个5,5'-位置上具有相同芳基的Pechmann
染料的3个N-类似物(芳基=苯基,2-
萘基,2-
噻吩基)和3,3'-位置上的羧基酯基。相应的5-芳基-
吡咯烷
酮酯。通过随后的N-甲基化制备在大多数有机溶剂中具有改善的溶解度的衍
生物。通过X射线衍射和密度泛函理论(DFT)计算,证实该
染料为E异构体,即具有全反式1,6-二芳基-
1,3,5-己三烯骨架,中心C C键有轻微扭曲。。没有观察到E / Z光异构化。完整分配1 H和13进行13 C NMR信号。根据随时间变化的激发能DFT计算,吸收光谱与最大值在572 nm(芳基=苯基)–643 nm(芳基= 2-
噻吩基)范围内非常相似。在溶液中未观察到荧光,而所有化合物在低温溶剂
玻璃(77 K)中均发出荧光,并且在红色/ IR区域检测到苯基和2-
萘基衍
生物的微弱固态荧光。