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Chemistry - A European Journal

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Relaxation (Nuclear physics), Gadolinium, Contrast media (Diagnostic imaging) -- Synthesis, Magnetic resonance imaging, Macrocyclic compounds, Ligands (Biochemistry)


Electron‐spin relaxation is one of the determining factors in the efficacy of MRI contrast agents. Of all the parameters involved in determining relaxivity it remains the least well understood, particularly as it relates to the structure of the complex. One of the reasons for the poor understanding of electron‐spin relaxation is that it is closely related to the ligand‐field parameters of the Gd3+ ion that forms the basis of MRI contrast agents and these complexes generally exhibit a structural isomerism that inherently complicates the study of electron spin relaxation. We have recently shown that two DOTA‐type ligands could be synthesised that, when coordinated to Gd3+, would adopt well defined coordination geometries and are not subject to the problems of intramolecular motion of other complexes. The EPR properties of these two chelates were studied and the results examined with theory to probe their electron‐spin relaxation properties


This is the pre-peer reviewed version of the following article: Borel, A., Bean, J. F., Clarkson, R. B., Helm, L., Moriggi, L., Sherry, A. D., & Woods, M. (2008). Towards the Rational Design of MRI Contrast Agents: Electron Spin Relaxation Is Largely Unaffected by the Coordination Geometry of Gadolinium (III)–DOTA‐Type Complexes. Chemistry–A European Journal, 14(9), 2658-2667, which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

Note: At the time of writing Mark Woods was affiliated with the University of Texas at Dallas.



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