New Fluorimetric Alkali and Alkaline Earth Metal Cation Sensors Based on Noncyclic Crown Ethers by Means of Intramolecular Excimer Formation of Pyrene

• DOI: 10.1021/jp981567t
• Publication Date: 2002-07-26T05:28:13Z
• Authors: Yoshio Suzuki; Tatsuya Morozumi; Hiroshi Nakamura; Masatsugu Shimomura; Takashi Hayashita; Richard A. Bartsh
• Keywords: Excimer; Alkaline earth metal; Proton NMR; Moiety

New fluorescent reagents, 2,2'-[oxybis(3-oxapentamethyleneoxy)]-bis[N-(1-pyrenylmethyl)benzamide)] (4) and its analogues (2, 3, 5) which have two pyrenes at the both terminals of polyoxyethylene compounds, were synthesized, their complexation behavior with alkaline earth cations was investigated by fluorescence spectrometry, lifetimes, 1H NMR spectrometry. These reagents (3−5) showed strong intramolecular excimer emissions around 480 nm in spectra. On metal cations, increase monomer emission 400 accompanied disappearance free observed. formed a 1:1 complex, order complex formation constants Ca2+ ≅ Sr2+ > Ba2+ Mg2+ Li+ for all reagents. spectra these complexes suggested helical structures complexes. Fluorescence spectral changes depended on chain length oxyethylene moiety cations. In cases, supported