Evolution of hollow nanosphere to microtube in the self-assembly of chiral dansyl derivatives and inversed circularly polarized luminescence

Here, we designed asymmetric (mDS) and symmetrical (dDS) chiral V-shaped molecules by linking one or two dansyl groups to trans-1,2-cyclohexane diamine and investigated the solventregulated structural transformation and inversed circularly polarized luminescence (CPL) in the self-assemblies. Upon increasing water volume fraction (fw) in the mixed solvent of water/acetonitrile, asymmetric mDS self-assembled into hollow nanospheres and microtubes, while solid nanospheres and solid microplates were corresponding to symmetric dDS. During this transformation process, the emission of mDS and dDS was changed from yellow-green to blue and cyan color, which was ascribed to twisted intramolecular charge transfer (TICT) and locally excited (LE) fluorescence of V-shaped DS molecules. The conformation of N,N-dimethyl groups with respect to naphthalene ring also led to the transformation of structures. These tubular and platelike structures had stronger and reversed CPL signals in comparison with spheroidal structures. The chiral information of DS assembly could be effective transferred to achiral Nile red via co-assembly strategy, which endowed Nile red exhibiting inversed induced CPL signal regulated by water fraction. This work provides a method for achieving a variety of self-assembled structures with adjustable chiroptical properties.