Observation of Circularly Polarized Luminescence of the Excimer from Two Perylene Cores in the Form of [4]Rotaxane

A perylene‐based [4]rotaxane was synthesized by the Sonogashira coupling of the 2:2 inclusion complex consisting of two alkynylperylenes and two γ‐cyclodextrins with terphenyl‐type stopper molecules. The [4]rotaxane showed orange emission attributable to the spatially restricted alkynylperylene excimer with a high fluorescence quantum yield of Φf=0.15. The excimer emission was circularly polarized as a result of the asymmetrically twisted perylene pair under the influence of chirality of γ‐cyclodextrin. The glum value of the excimer emission was determined to be −2.1×10−2 at 573 nm, as large as those of the corresponding known pyrene‐based series. This is the first example, in which circularly polarized luminescence was clearly observed from the excimer of a pair of perylene cores. A doubly perylene‐threaded [4]rotaxane was synthesized by using an amphiphilic alkynylperylene as an axle component. The [4]rotaxane showed only orange excimer emission that was circular polarized with a high |glum| value. Although the excited state of perylene is short‐lived, the spatially restricted pair was forced to form an excimer twisted in an asymmetric manner (see figure).