Multi-emission regulation of trans-4-[4-(N,N-dimethylamino)styryl]pyridine with a mild host-guest strategy based on H-type β-zeolite

In this work, a mild host-guest strategy based on H-type molecular sieves was developed to regulate the fluorescence emissions of D-π-A molecules under the synergetic effect of aggregation and protonation. Specifically, trans-4-[4-(N,N-dimethylamino)styrylpyridine (DMSP) as a typical D-π-A molecule was adsorbed into the nanopores of H-type β-zeolite. DMSP possessed inherent cyan fluorescence with an emission band around 476 nm. After DMSP entered the acidic nanopores of H-type β-zeolite, the pyridinyl nitrogen of DMSP was protonated, so the intramolecular charge transfer of DMSP was enhanced. This alteration in the structure made the fluorescence emission of DMSP red-shifted. Meanwhile, the J-aggregate of DMSP was generated under its high content in the nanopores of H-type β-zeolite, red-shifting the emission of DMSP as well. Under the synergetic effect of J-aggregation and protonation, a wide-tuning emission of DMSP was acquired by altering the loading amount of DMSP or the Al/Si ratio of H-type β-zeolite. With the regulation of H-type β-zeolite, the fluorescence of DMSP was expanded from cyan to red, accompanied by the red shift of the emission wavelength from 476 nm to 625 nm. Theses host-guest materials of DMSP with H-type β-zeolite had potential applications in multicolor display.