Elucidating the Impact of Molecular Structure on the 19 F NMR Dynamics and MRI Performance of Fluorinated Oligomers.

To understand molecular factors that impact the performance of polymeric 19 F magnetic resonance imaging (MRI) agents, a series of discrete fluorinated oligoacrylates with precisely defined structure were prepared through the combination of controlled polymerization and chromatographic separation techniques. These discrete oligomers enabled thorough elucidation of the dependence of 19 F NMR and MRI properties on molecular structure, for example, the chain length. Importantly, the oligomer size and dispersity strongly influence NMR dynamics ( T 1 and T 2 relaxation times) and MR imaging properties with higher signal-to-noise ratio (SNR) observed for oligomers with longer chain length and shorter T 1 . Our approach enables an effective pathway and thus opportunities to rationally design effective polymeric 19 F MR imaging agents with optimized molecular structure and NMR relaxivity.