Synthesis and Relaxometric Properties of Gadolinium(III) Complexes of New Triazine-Based Polydentate Ligands

Two new derivatives based on an s‐triazine structural motif were synthesized by attaching two 2,2′‐hydrazinylidenebis[acetic acid] moieties to the triazine ring to reach an overall heptadenticity for the complexation of lanthanide(III) cations. The remaining reactive site was exploited for the subst...

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Bibliographic Details
Published in:Helvetica chimica acta 2009-11, Vol.92 (11), p.2414-2426
Main Authors: Tei, Lorenzo, Benzi, Marina, Kielar, Filip, Botta, Mauro, Cavallotti, Camilla, Giovenzana, Giovanni Battista, Aime, Silvio
Format: Article
Language:English
Subjects:
Gadolinium complexes
Luminescence
Micellisation
Nuclear Magnetic Relaxation Dispersion (NMRD)
Relaxometric properties
Triazine ligands
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Summary:Two new derivatives based on an s‐triazine structural motif were synthesized by attaching two 2,2′‐hydrazinylidenebis[acetic acid] moieties to the triazine ring to reach an overall heptadenticity for the complexation of lanthanide(III) cations. The remaining reactive site was exploited for the substitution with a functionizable amino group (see H4L1) and a lipophilic moiety (see H4L2). Luminescence‐lifetime determinations revealed the presence of a single H2O molecule coordinated for [Eu(L1)]. A complete 1H‐NMR relaxometric study was carried out for the octacoordinated [Gd(L1)] and [Gd(L2)] complexes. A remarkably long H2O residence lifetime (298τM=5.2 μs) was found by 17O‐NMR in the case of [Gd(L1)]. Micelle formation of the lipophilic complex [Gd(L2)] was evidenced, the critical micellization concentration (cmc) determined, and relaxometric properties of the system investigated.
ISSN:0018-019X
1522-2675
DOI:10.1002/hlca.200900189