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Bright Mono‐aqua Europium Complexes Based on Triazacyclononane That Bind Anions Reversibly and Permeate Cells Efficiently
Author(s) -
Butler Stephen J.,
McMahon Brian K.,
Pal Robert,
Parker David,
Walton James W.
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201301273
Subject(s) - europium , chemistry , permeation , inorganic chemistry , nuclear chemistry , membrane , organic chemistry , biochemistry , ion
A series of five europium(III) complexes has been prepared from heptadentate N 5 O 2 ligands that possess a brightness of more than 10 m M −1 cm −1 in water, following excitation over the range λ =330–355 nm. Binding of several oxy anions has been assessed by emission spectral titrimetric analysis, with the binding of simple carboxylates, lactate and citrate involving a common ligation mode following displacement of the coordinated water. Selectivity for bicarbonate allows the rapid determination of this anion in human serum, with K d =37 m M (295 K). The complexes are internalised quickly into mammalian cells and exhibit a mitochondrial localisation at early time points, migrating after a few hours to reveal a predominant lysosomal distribution. Herein, we report the synthesis and complexation behaviour of strongly emissive europium (III) complexes that bind oxy‐anions in aqueous media with an affinity and selectivity profile that is distinctively different from previously studied systems.