Remarkably enhanced excimer formation of naphthylacetate in cation-charged gamma-cyclodextrin.

[reaction: see text] 6(A),6(D)-Bispyridinio-appended gamma-cyclodextrin effectively enhanced the excimer fluorescence of 2-naphthylacetate. This increase derived from the increase of formation of the 1:2 complex between the cation-charged gamma-cyclodextrin and 2-naphthylacetate by the electrostatic interaction between the host and the guest.