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Synthesis and Relaxometric Properties of Gadolinium(III) Complexes of New Triazine‐Based Polydentate Ligands
Author(s) -
Tei Lorenzo,
Benzi Marina,
Kielar Filip,
Botta Mauro,
Cavallotti Camilla,
Giovenzana Giovanni Battista,
Aime Silvio
Publication year - 2009
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200900189
Subject(s) - chemistry , triazine , denticity , gadolinium , lanthanide , moiety , micelle , molecule , stereochemistry , crystallography , polymer chemistry , organic chemistry , aqueous solution , crystal structure , ion
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 H 4 L1 ) and a lipophilic moiety (see H 4 L2 ). Luminescence‐lifetime determinations revealed the presence of a single H 2 O molecule coordinated for [Eu( L1 )]. A complete 1 H‐NMR relaxometric study was carried out for the octacoordinated [Gd( L1 )] and [Gd( L2 )] complexes. A remarkably long H 2 O residence lifetime ( 298 τ M =5.2 μs) was found by 17 O‐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.