PMSE 171 |
| Dendronized carborane containing polymers were successfully synthesized by the “graft-from” approach using a divergent dendron growth to up to the fourth generation. Nitroxide mediated polymerization (NMP) proved effective in polymerizing the carborane-functionalized styrenic monomer to produce a well defined polymer with high boron content (~26% B by weight) and narrow polydispersity index (PDI < 1.1). Dendronization of the carborane functionalized polymer was achieved via deprotonation of the acidic carborane proton in the para position followed by reaction of the polyanion with a benzylidene protected bisMPA anhydride. Complete removal of the benzylidene protecting group was achieved by a combination of Pd-catalyzed hydrogenolysis and acid-catalyzed deprotection. This is a key step to the successful synthesis of monodisperse higher generation dendronized polymers. Carborane containing dendronized polymers 1-4 generation dendrons were synthesized with a maximum molecular weight (Mw) of ca. 114 kDa ([G-4]-(OH)16). The fourth generation polymer, [G-4]-(OH)16, is water soluble at a concentration of 1 mg/mL and affords a B content of about 12% by weight. The products were analyzed by 1H and 13C NMR and SEC.
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Polymers for Biomedical Applications
8:30 AM-12:10 PM, Tuesday, 12 September 2006 San Francisco Marriott -- Salon B1, Oral
Division of Polymeric Materials: Science & Engineering |