Highly Soluble Tris-hydroxypyridonate Gd(III) Complexes with Increased Hydration Number, Fast Water Exchange, Slow Electronic Relaxation, and High Relaxivity1

• Published in: Journal of the American Chemical Society Vol. 129; no. 7; pp. 1870 - 1871
• Main Authors: Werner, Eric J., Avedano, Stefano, Botta, Mauro, Hay, Benjamin P., Moore, Evan G., Aime, Silvio, Raymond, Kenneth N.
• Format: Journal Article
• Language: English
• Published: United States 21-02-2007
• Subjects: GADOLINIUM COMPLEXES; HYDRATES; HYDROXIDES; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; magnetic resonance imaging; molecular mechanics modeling; MOLECULAR MODELS; MRI; PYRIDINE; RELAXATION TIME; STRESS RELAXATION; SYNTHESIS
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja068026z

The design, synthesis, and relaxivity properties of a highly soluble TACN-capped hydroxypyridonate Gd(III) complex are presented. Molecular mechanics modeling was used to help design a complex capable of possessing three water molecules in the inner metal coordination sphere, an attractive property for high-relaxivity MRI contrast agents. The measured relaxivity of 13.1 mM-1s-1 is consistent with three coordinated waters and represents one of the highest known relaxivities of any low-molecular weight Gd complex. An extremely fast water exchange rate, long electronic relaxation time, and unique pH dependent relaxivity of the complex are also discussed. B.P.H. acknowledges support from the Environmental Management Science Program, Office of Science, U.S. Department of Energy (grant 73759). Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.