科研之友
微信
新浪微博
Facebook
分享链接
摘要
A series of D-A typed phenothiazine derivatives functionalized by formyl group (PCAn, n = 1, 2, 4 and 6) with different lengths of N-alkyl chains have been designed and synthesized to systematically investigate the effect of chain length on their solid-state fluorescence properties. The results showed that these compounds emitted strong fluorescence in solutions and solid states with 52%, 42%, 49% and 45% solidstate absolute fluorescence quantum yield (43F), respectively. Their emission wavelengths were strongly affected by solvent polarity, indicating intramolecular charge transfer (ICT) transitions. Interestingly, PCAn solids exhibit not only naked-eye visible and reversible mechanochromic behavior, but chain length-dependent emission properties. PCA1 shows smaller fluorescence spectrum shifts (22 nm) under mechanical force stimuli. Homologs with longer alkyl chains exhibit similar mechanochromic behaviors but larger fluorescence contrasts after grinding except for PCA6. Moreover, the fluorescence emission of ground solid PCA1 and PCA4 can recover at room temperature, PCA2 need high temperatures for fluorescence to be restored, and XRD and DSC revealed that the transformation between crystalline and amorphous states upon various external stimuli was responsible for the MFC behavior. This work demonstrates the feasibility of tuning the solid-state optical properties of fluorescent organic compounds by combining the simple alteration of chemical structure and the physical change of aggregate morphology under external stimuli.
- 出版日期2017-12
- 单位山西师范大学
