Related Experiment Video
Updated: Oct 3, 2025

Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
Ratiometric pH-Responsive 19F Magnetic Resonance Imaging Contrast Agents Based on Hydrazone Switches
Dawid Janasik1, Krzysztof Jasiński2, Władysław P Węglarz2
1Department of Chemical Organic Technology and Petrochemistry, Silesian University of Technology Krzywoustego 4,44-100 Gliwice, Poland.
Abstract:
Hydrazone-based molecular switches serve as efficient ratiometric pH-sensitive agents that can be tracked with 19F NMR/MRI and 1H NMR. Structural changes induced between pH 3 and 4 lead to signal appearance and disappearance at 1H and 19F NMR spectra allowing ratiometric pH measurements. The most pronounced are resonances of the CF3 group shifted by 1.8 ppm with 19F NMR and a hydrazone proton shifted by 2 ppm with 1H NMR.
More Related Videos
Related Concept Videos
Magnetic Resonance Imaging
Other Nuclides: 31P, 19F, 15N NMR
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a...

