472277 Magnetic and Biocompatible Polymerized Ionic Liquids
Herein, we present a magnetic and biocompatible PIL based on poly(ethylene glycol) (i.e., PEG) and the ionic liquid anion tetrachloroferrate(III) (i.e., FeCl4-). We illustrate a molecular design strategy based on a combination of epoxide ring opening anionic polymerization and thiol-ene click chemistry that allows for exquisite control over the molecular structure of the polymer and guarantees scalability appropriate for extensive physical characterization. PIL containing FeCl4- is paramagnetic with a magnetic susceptibility at 30 oC of 30x10-6 emu/g.Oe, as characteristic of materials based on anions containing transition metals with partially filled d-orbitals. Additionally, the PIL significantly modifies the magnetic environment experienced by the 1H of water, as revealed by a decrease in the spin-lattice relaxation time (i.e., T1) of 1H determined from Nuclear Magnetic Resonance (i.e., NMR) from 8 to 0.3 seconds. The structure-property relationships demonstrated in this work makes PILs based on PEG and FeCl4- suitable as a T1-weighted MRI contrast agent. The magnetic and biocompatible nature of PILs is promising for development of novel therapeutic agents (i.e., drugs, proteins, antibodies) based on polymer conjugates that exhibit controlled residence time within the human body; and magnetic functionality for MRI imaging, and facilitated targeting.