Abstract
Multilevel green fluorescent supramolecular assemblies that derived from macrocyclic confinement–activated yellow fluorescent pseudo[5]rotaxane and subsequently assembled with anionic cyclodextrin derivative sulfobutylether–β–cyclodextrin (SBE–β–CD) were reported. Possessing four cationic coumarin arms, the coumarin–modified dibenzo–24–crown–8 guest (G) could be encapsulated by cucurbit[7]uril (CB[7]) at a 4:1 host–guest stoichiometry to form pseudo[5]rotaxane (G@CB[7]4) in the manner of dynamic slipping, which not only extended the fluorescence intensity of G by 53 times, but also increased the fluorescence lifetime by 5.8–fold from 0.65 to 3.76 ns. Subsequently, SBE–β–CD was co–assembled with G@CB[7]4 to control the topological morphology from small nanoparticles to larger ones, further enhancing fluorescence by 9.9 times along with a blue shift from 530 nm to 515 nm through cascade confinement. Compared with the direct assembly of G and SBE–β–CD through electrostatic interactions, only slight fluorescence increase was shown. After doping the NIR dye sulforhodamine 101 (SR101) acceptor, the G@CB[7]4@SBE–β–CD/SR101 exhibited high energy transfer efficiency to 79%, accompanied by the color changed from green to red under 365 nm irradiation. Moreover, the multicolor tunable emission could be achieved by adding dibenzylammonium chloride to the solution of G@CB[7]4, G@CB[7]4@SBE–β–CD and G@CB[7]4@SBE–β–CD/SR101. Ultimately, the final assemblies were used in multicolor luminescence information storage and cells imaging.
Published Version
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