NMR relaxometric studies of Gd(III) complexes with heptadentate macrocyclic ligands

Aime, Silvio; Botta, Maurizio; Crich, Simonetta Geninatti; Giovenzana, Giovanni B.; Pagliarin, Roberto; Sisti, Massimo; Terreno, Enzo

doi:10.1002/(sici)1097-458x(199806)36:13<s200::aid-omr324>3.0.co;2-h

Cited by 146 publications

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“…60 ± 80 %) than those measured for the parent compounds [Gd(dota)], [Gd(dtpa)], and [Gd(do3a)]. [30] The increase in the relaxivity is mainly due to the increase in t R caused by the presence of the three bulky residues on the surface of the metal complexes.…”

Section: Resultsmentioning

confidence: 99%

High-Relaxivity Contrast Agents for Magnetic Resonance Imaging Based on Multisite Interactions between aβ-Cyclodextrin Oligomer and Suitably Functionalized GdIII Chelates

Aime

Botta

Fedeli³

et al. 2001

Chem. Eur. J.

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The results reported in this work show that tightly assembled adducts formed by trisubstituted GdIII complexes and a beta-CD multimer (Poly-beta-CD, d.p. ca. 12) may represent very interesting candidates for novel MRI applications wherein a high number of paramagnetic ions endowed with high relaxivity (per GdIII ion) are necessary. The relaxivities found for the paramagnetic adducts represent a remarkable step forward on the relaxivity scale. However, a detailed investigation of the determinants of the relaxation enhancement in these systems shows that their relaxivities are still limited by a nonoptimal tauR and a relatively long exchange lifetime of the coordinated water(s). Moreover, the exchange rate of the water molecule(s) coordinated to the GdIII ion further decreases upon binding to the Poly-beta-CD. It is suggested that this finding is related to the structural properties of the supramolecule, which brings a high density of hydroxyl groups into the proximity of the "guest" complexes, and this yields an overall reinforcement of the hydrogen-bonding network involving the coordinated water(s). On the other hand, such a tight arrangement appears responsible for an enhanced contribution to the observed relaxivity arising from water molecules in the second coordination sphere of the metal center.

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Section: Resultsmentioning

confidence: 99%

High-Relaxivity Contrast Agents for Magnetic Resonance Imaging Based on Multisite Interactions between aβ-Cyclodextrin Oligomer and Suitably Functionalized GdIII Chelates

Aime

Botta

Fedeli³

et al. 2001

Chem. Eur. J.

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“…The Ln(PCTA- [12]) complexes were studied in more detail [341][342][343]. The Eu 3+ complex is quite stable (log k EuL = 18.48) [341] and the Gd 3+ complex, with q = 2, has a much faster water exchange rate than [Gd(DOTA)(H 2 O)] − [343].…”

Section: Pcta and Derivativesmentioning

confidence: 99%

“…The Eu 3+ complex is quite stable (log k EuL = 18.48) [341] and the Gd 3+ complex, with q = 2, has a much faster water exchange rate than [Gd(DOTA)(H 2 O)] − [343]. A temperature dependent 1 H and 13 C NMR study of the Ln(PCTA- [12]) (Ln = Eu, Yb) complexes has shown the presence of two interconverting isomers of quite different populations [341].…”

Section: Pcta and Derivativesmentioning

confidence: 99%

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Structure, Dynamics, and Computational Studies of Lanthanide‐Based Contrast Agents

Peters

Djanashvili

Geraldes

et al. 2013

The Chemistry of Contrast Agents in Medical Magnetic Resonance Imaging

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“…In the case of the symmetrical substitution, the "naked" macrocycle is prepared in the first step and the pendants are introduced in the second step. This strategy was used for preparation of tri(substituted) ligands with acetate (H 3 PCTA) [340,350], glutarate [351], propionate [352], and acetamide pendant arms [353] as well as for phosphonate derivative (H 6 PCTP) [354,355]. A different strategy can be used for ligands with mixed pendant arms.…”

Section: H 3 Pcta and Related Ligandsmentioning

confidence: 99%

Synthesis and Characterization of Ligands and their Gadolinium(III) Complexes

Kotek¹,

Kubíček²,

Hermann³

et al. 2013

The Chemistry of Contrast Agents in Medical Magnetic Resonance Imaging

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NMR relaxometric studies of Gd(III) complexes with heptadentate macrocyclic ligands

Cited by 146 publications

References 0 publications

High-Relaxivity Contrast Agents for Magnetic Resonance Imaging Based on Multisite Interactions between aβ-Cyclodextrin Oligomer and Suitably Functionalized GdIII Chelates

High-Relaxivity Contrast Agents for Magnetic Resonance Imaging Based on Multisite Interactions between aβ-Cyclodextrin Oligomer and Suitably Functionalized GdIII Chelates

Structure, Dynamics, and Computational Studies of Lanthanide‐Based Contrast Agents

Synthesis and Characterization of Ligands and their Gadolinium(III) Complexes

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