19F VT NMR: Novel Tm3+ and Ce3+ Complexes Provide New Insight into Temperature Measurement Using Molecular Sensors.

Abstract

In the past few decades, magnetic resonance spectroscopy (MRS) and MR imaging (MRI) have developed into a powerful non-invasive tool for medical diagnostic and therapy. Especially 19F MR shows promising potential because of the properties of the fluorine atom and the negligible background signals in the MR spectra. The detection of temperature in a living organism is quite difficult and usually, external thermometers or fibers are used. Temperature determination via MRS needs temperature-sensitive contrast agents. This article reports first results of solvent and structural influences on the temperature sensitivity of 19F NMR signals of chosen molecules. By using this chemical shift sensitivity, a local temperature can be determined with a high precision. Based on this preliminary study, we synthesized five metal complexes and compared the results of all variable temperature measurements temperature. It is shown that the highest 19F MR signal temperature dependence is detectable for a fluorine nucleus in a Tm3+-complex.