一种含Tröger碱单元的AIE分子的独特力致荧光增强 行为

We demonstrate a unique mechano-luminochromic (MLC) effect of an aggregation-induced emission (AIE)-active luminogen (AIEgen), DTPE-TB, which is characterized by the evidently changed emission intensity but unimpressively shifted emission colors of the molecular solid. This behavior is termed mechanofluoro enhancement (MFE), which is quite distinct from the commonly reported AIEgens with the MLC property. The MFE effect originates from the special design of the DTPE-TB molecule, in which the two tetraphenylethene (TPE) units play the role of AIE, and the Tröger's base unit takes the part of a mechanical force supporter. Therefore, when the DTPE-TB molecular solid is subjected to mechanical forces, the Λ-shaped Tröger's base unit releases external forces by changing its dihedral angle. Meanwhile, the TPE units nearly keep unchanged in the molecular arrangement. Accordingly, the DTPE-TB solid shows an evidently enhanced emission under pressure due to the aggravated restriction of intramolecular motions but a slightly shifted emission wavelength due to the tiny variations in molecular packing.