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A Class of Fe III Macrocyclic Complexes with Alcohol Donor Groups as Effective T 1 MRI Contrast Agents
Abstract Early studies suggested that FeIIIcomplexes cannot compete with GdIIIcomplexes as T1MRI contrast agents. Now it is shown that one member of a class of high‐spin macrocyclic FeIIIcomplexes produces more intense contrast in mice kidneys and liver at 30 minutes post‐injection than does a commercially used GdIIIagent and also produces similar T1relaxivity in serum phantoms at 4.7 T and 37 °C. Comparison of four different FeIIImacrocyclic complexes elucidates the factors that contribute to relaxivity in vivo including solution speciation. Variable‐temperature17O NMR studies suggest that none of the complexes has a single, integral inner‐sphere water that exchanges rapidly on the NMR timescale. MRI studies in mice show large in vivo differences of three of the FeIIIcomplexes that correspond, in part, to their r1relaxivity in phantoms. Changes in overall charge of the complex modulate contrast enhancement, especially of the kidneys.
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- Award ID(s):
- 1710224
- PAR ID:
- 10128041
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 59
- Issue:
- 6
- ISSN:
- 1433-7851
- Page Range / eLocation ID:
- p. 2414-2419
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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