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A Class of Fe III Macrocyclic Complexes with Alcohol Donor Groups as Effective T 1 MRI Contrast Agents
Author(s) -
Snyder Eric M.,
Asik Didar,
Abozeid Samira M.,
Burgio Ariel,
Bateman Gage,
Turowski Steven G.,
Spernyak Joseph A.,
Morrow Janet R.
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201912273
Subject(s) - in vivo , contrast (vision) , gadolinium , chemistry , nuclear magnetic resonance , alcohol , mri contrast agent , genetic algorithm , crystallography , physics , biochemistry , organic chemistry , biology , microbiology and biotechnology , evolutionary biology , optics
Early studies suggested that Fe III complexes cannot compete with Gd III complexes as T 1 MRI contrast agents. Now it is shown that one member of a class of high‐spin macrocyclic Fe III complexes produces more intense contrast in mice kidneys and liver at 30 minutes post‐injection than does a commercially used Gd III agent and also produces similar T 1 relaxivity in serum phantoms at 4.7 T and 37 °C. Comparison of four different Fe III macrocyclic complexes elucidates the factors that contribute to relaxivity in vivo including solution speciation. Variable‐temperature 17 O 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 Fe III complexes that correspond, in part, to their r 1 relaxivity in phantoms. Changes in overall charge of the complex modulate contrast enhancement, especially of the kidneys.