Design and Synthesis of Fluorinated Dendrimers for Sensitive ¹⁹F MRI

To achieve high sensitivity for ¹⁹F MRI, a class of novel dendritic molecules with multiple pseudosymmetrical fluorines was designed and efficiently synthesized. Through iterative bromination and Williamson ether synthesis under mild conditions, a fluorinated dendrimer with 540 pseudosymmetrical fluorines was conveniently prepared without performing the group protection in a convergent way. The dendrimer is characterized by a strong ¹⁹F NMR peak and short relaxation times. Eventually, an appreciably enhanced ¹⁹F MRI at an extremely low concentration (18.5 μM) was achieved, which demonstrated the potential utility of such dendritic molecules in highly sensitive ¹⁹F MRI.