Circularly polarized luminescence enables selective recognition of electron-deficient acceptors
Due to the integration of excited state information and chiral information,circularly polarized luminescence can provide an additional information channel for common fluorescent probes,which is expected to play a unique role in the field of molecular recognition.In this work,we designed and synthesized a Y-type pyrene-glutamate chiral molecule(Py-Glu)containing two pyrene chromophores.Selective recognition of octafluoronaphthalene(OFN)among 11 electron-deficient acceptors was realized by using the turn-on circularly polarized luminescence from Py-Glu/acceptor co-assemblies.Py-Glu self-assembled into nanosphere structures at a low concentration(1 × 10-5 M in N,N-dimethylformamide(DMF)/water,v/v=1∶9),which could transform into nanofibers upon nanosphere fusion by increasing concentration to 3 × 10-4 M.Obvious circular dichroism signals of the nanospheres and nanofibers indicated an effective chirality transfer from molecular to supramolecular level.Co-assembly of electron-rich Py-Glu with a library of electron-deficient halogenated or cyano-substituted aromatic hydrocarbons caused irregularly changed fluorescence intensity,which was difficult to achieve precise molecular recognition.In contrast,L-Py-Glu/OFN system showed the ability of turn-on circularly polarized luminescence(CPL)while other acceptors remained CPL silence,which provided a new method for the selective recognition of electron-deficient acceptors by circularly polarized luminescence.