Circularly polarized luminescence (CPL) characteristics of hydrophobic pyrene derivatives/γ-cyclodextrin (γ-CD) complexes in aqueous solution dissolved by grinding

Circularly polarized luminescence (CPL) organic dyes are currently receiving a great interest, but there are still not many reported observations of CPL spectra of hydrophobic dyes from aqueous solution. We have prepared hydrophobic pyrene derivatives and dissolved them into aqueous solutions with γ -cyclodextrin ( γ -CD) by using grinding technique. Among these derivatives, (pyrene-1-carbonyl)serine (PySer) forms a spatially restricted dimer in the hydrophobic chiral cavity of γ -CD and exhibits excimer emission with a high quantum yield of Φ f = 0.68. In addition, circular dichroism and CPL signals were induced for the complex. The strong g CPL value of g CPL = + 2.2 × 10 −3 was obtained, which may be attributed to the interaction between the hydroxyl groups in the side chain of PySer with those of γ -CD and it strengthens the chiral dimeric structure. Graphic abstract