Complexation behaviors of polyether-type fluorescent reagents having anthracene units at their terminals

A, new fluorescent reagent,N,N'-(4,7,10-trioxatridecane-1,13-diyl)bis(anthr acene-9-carbonamide)(5), and its analogues(1 similar to 4 and 6), which hav e two anthracene moieties at both terminals of linear polyethers, were synt hesized. Their complexation behavior with alkaline earth cations was invest igated by fluorescence spectrometry, fluorescence lifetime, and H-1 NMR spe ctrometry. When metal ions were added to these reagent solutions, fluoresce nce spectral changes were observed. In particular, 5 showed a drastic chang e in the fluorescence spectra accompanied by metal ion binding. The fluores cence spectra of 5 completely changed from that of monomer to excimer emiss ion. All reagents formed a 1 : 1 complex with alkaline earth cations. The H -1 NMR spectra of 5 with alkaline earth cations suggested the stacking of t wo anthracene moieties with each other. However, the interactions between t wo anthracenes were weak on the ground state for the other compounds (1 sim ilar to 4 and 6).