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

Abstract

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. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.