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APTRA-based luminescent lanthanide complexes displaying enhanced selectivity for Mg2+

Parker, D.; Walter, E.R.H.; Williams, J.A.G.

APTRA-based luminescent lanthanide complexes displaying enhanced selectivity for Mg2+ Thumbnail


E.R.H. Walter


A series of three europium(III) complexes has been created in which an APTRA moiety has been integrated into the sensitising chromophore (APTRA = o‐aminophenol‐N,N,N‐triacetate). The constitutionally isomeric complexes EuL1 and EuL2 feature the APTRA unit linked to a metal‐bound pyridine ring through an alkynyl unit, differing according to the disposition of the APTRA substituents relative to the C≡C unit (para‐N and para‐O respectively). In EuL3, the APTRA ring is directly bonded to the Eu‐coordinated pyridine (para‐O). The metal binding affinities for magnesium, calcium and zinc ions have been measured using emission and excitation spectroscopy. The pyridylalkynylaryl systems, EuL1 and EuL2, offer superior affinity and selectivity for Mg2+. The Mg2+ affinities are surprisingly very different from prior studies on structurally related systems that incorporate organic fluorophores as reporters, as opposed to the macrocyclic Eu complex moiety. A much reduced affinity for calcium and zinc ‐ possibly arising from the lower donor ability of the aryl N or O atoms arising from extended conjugation ‐ means that magnesium ion concentrations can be measured directly in serum for the first time, using such an approach. An apparent dissociation constant for magnesium binding of Kd = 2.4 mM was calculated in the serum background.

Journal Article Type Article
Acceptance Date Mar 13, 2018
Online Publication Date Mar 13, 2018
Publication Date May 28, 2018
Deposit Date Mar 22, 2018
Publicly Available Date Mar 13, 2019
Journal Chemistry - A European Journal
Print ISSN 0947-6539
Electronic ISSN 1521-3765
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 24
Issue 30
Pages 7724-7733
Public URL


Accepted Journal Article (1.3 Mb)

Copyright Statement
This is the peer reviewed version of the following article: Parker, D., Walter, E. R. H. & Williams, J. A. G. (2018). APTRA-based luminescent lanthanide complexes displaying enhanced selectivity for Mg2+. Chemistry - A European Journal 24(30): 7724-7733, which has been published in final form at This article may be used for non-commercial purposes in accordance With Wiley-VCH Terms and Conditions for self-archiving.

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