Sponsor
We thank the National Institutes of Health (EB-04285, M.W.) and (CA-115531 and RR-02584, A.D.S.) (EB-04609, J.R.M.) and the Robert A. Welch Foundation (AT-584) for financial support of this work.
Published In
Journal of the American Chemical Society
Document Type
Post-Print
Publication Date
8-9-2006
Subjects
Macrocyclic compounds, Contrast media (Diagnostic imaging) -- Synthesis, Ligands (Biochemistry), Magnetic resonance imaging
Abstract
Paramagnetic lanthanide(III) complexes that contain hyperfine-shifted exchangeable protons offer considerable advantages over diamagnetic molecules as chemical exchange saturation transfer (CEST) agents for MRI. As part of a program to investigate avenues to improve the sensitivity of such agents, the CEST characteristics of europium(III) macrocyclic complexes having appended hydroxyethyl groups were investigated. The CEST spectrum of the asymmetrical complex, EuCNPHC3+, shows five distinct peaks for each magnetically nonequivalent exchangeable proton in the molecule. The CEST spectra of this complex were fitted to NMR Bloch theory to yield exchange rates between each of six exchanging proton pools (five on the agent plus bulk water). Exchange between the Eu3+-bound hydroxyl protons and bulk water protons was slow in dry acetonitrile but accelerated incrementally upon stepwise addition of water. In pure water, exchange was too fast to observe a CEST effect. The utility of this class of europium(III) complex for CEST imaging applications is ultimately limited by the small chemical shifts induced by the hydroxyl-appended ligands of this type and the resulting small Δω values for the exchangeable hydroxyl protons.
DOI
10.1021/ja061498t
Persistent Identifier
https://archives.pdx.edu/ds/psu/32565
Citation Details
Woods, M., Woessner, D. E., Zhao, P., Pasha, A., Yang, M. Y., Huang, C. H., ... & Sherry, A. D. (2006). Europium (III) macrocyclic complexes with alcohol pendant groups as chemical exchange saturation transfer agents. Journal of the American Chemical Society, 128(31), 10155-10162.
Description
This is the authors' version of a paper that subsequently appeared in the ournal of the American Chemical Society, vol. 128, no. 31: 10155–10162. The version of record may be found at https://dx.doi.org/10.1021/ja061498t.
Note: At the time of writing Mark Woods was affiliated with the University of Texas at Dallas.