title: A highly selective bicyclic fluoroionophore for the detection of lithium ions.
abstract: The macrobicyclic molecule, 21-(9-anthrylmethyl)-4,17,13,16-tetraoxa-1,10,21-triazabicyclo [8.8.5]tricosane-19,23-dione, I, was designed, synthesized and characterized as a fluoroionophore for the selective, optical detection of lithium ions. Compound I is based on a bridged diazacrown structure, which provides a semirigid binding framework. Binding takes place by electrostatic interactions between the oxygen atoms of the crown and the cation and is transduced to fluorescence emission from an attached anthracene fluorophore. In a 75:25 dichloromethane/tetrahydrofuran solvent mixture, I acts as an intramolecular electron transfer "off-on" fluorescence switch, exhibiting a greater than 190-fold enhancement in fluorescence emission intensity in the presence of lithium ions. The relative selectivity of I for lithium ions over sodium, potassium and ammonium ions was found to be log K(Li+,Na+) approximately -3.36, log K(Li+,K+) approximately -1.77 and log K(Li+,NH4+) approximately -2.78.
authors.affiliation: Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA 01609, USA.
authors.forename: Nantanit
authors.initials: N
authors.lastname: Wanichacheva
authors.forename: Nantanit
authors.initials: N
authors.lastname: Wanichecheva
authors.forename: John S
authors.initials: JS
authors.lastname: Benco
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Lambert
authors.forename: W Grant
authors.initials: WG
authors.lastname: McGimpsey
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry; D007202:Indicators and Reagents; D007477:Ions; D008094:Lithium / Q000032:analysis*; D008958:Models, Molecular; D013050:Spectrometry, Fluorescence
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D007202:Indicators and Reagents; D007477:Ions; D008094:Lithium