High relaxivity confined to a small molecular space: a metallostar-based, potential MRI contrast agent.

Good things come in small packages: For its moderate molecular weight, the metallostar complex [Fe{Gd2L(H2O)4}3]4− (see picture; L is a bipyridine–poly(aminocarboxylate) derivative) displays exceptionally high proton relaxivity, which is explained in terms of a rigid supramolecular structure, two inner-sphere water molecules with a near-optimal exchange rate, and six efficiently relaxing GdIII centers confined to a small molecular space.

[1]  É. Tóth,et al.  The impact of rigidity and water exchange on the relaxivity of a dendritic MRI contrast agent. , 2002, Chemistry.

[2]  L. Helm,et al.  Structural and Dynamic Parameters Obtained from 17O NMR, EPR, and NMRD Studies of Monomeric and Dimeric Gd3+ Complexes of Interest in Magnetic Resonance Imaging: An Integrated and Theoretically Self-Consistent Approach1 , 1996 .

[3]  E C Wiener,et al.  Development of a tumor-targeting MR contrast agent using the high-affinity folate receptor: work in progress. , 2000, Investigative radiology.

[4]  A. Merbach,et al.  Novel heteroditopic chelate for self-assembled gadolinium(III) complex with high relaxivity. , 2004, Chemical communications.

[5]  J A Frank,et al.  Synthesis and relaxometry of high‐generation (G = 5, 7, 9, and 10) PAMAM dendrimer‐DOTA‐gadolinium chelates , 1999, Journal of magnetic resonance imaging : JMRI.

[6]  V. Jacques,et al.  Designing new MRI contrast agents: a coordination chemistry challenge , 1999 .

[7]  Éva Tóth,et al.  The Role of Water Exchange in Attaining Maximum Relaxivities for Dendrimeric MRI Contrast Agents , 1996 .

[8]  R. Muller,et al.  A tripod gadolinium(III) poly(amino carboxylate) relevant to magnetic resonance imaging: structural and dynamical 17O NMR and 1H NMRD studies , 1998 .

[9]  J. Sieler,et al.  Strukturen zweier isomerer Gadolinium(III)-Polyaminopolycarboxylate -Argumente für signifikante Unterschiede ihrer 1H-NMR-Relaxation/Structures of Two Isomeric Gadolinium(III) Polyamino Polycarboxylates -Relation to their Significant Differences in 1H NMR Relaxation , 1997 .