Bis-ureidodeazapterin (Bis-DeAP) as a general route to supramolecular star polymers

Supramolecular recognition unit Bis-DeAP, 1, containing two high affinity hydrogen-bonding acceptor-acceptor-donor-donor (AADD) arrays was designed to self-assemble into cyclic assemblies. It was prepared through a highly scalable synthesis and was further functionalized with 2-bromo-2-methylpropanoyl bromide and used to initiate the polymerization of methylmethacrylate (MMA). Bis-DeAPPMMA polymers quantitatively self-assembled into star polymers in toluene. In DMF Bis-DeAP-PMMA forms a mixture of star polymers and unassembled polymers. Bis-DeAP was also functionalized with polyethylene glycol (PEG) polymers. The Bis-DeAP-PEG polymers formed star polymers in DMF; however, higher molecular weight polymeric assembles that varied with concentration were observed in water. Mixing studies in toluene indicated that the self-assembled star polymers are kinetically stable and resist mixing even at elevated temperatures. In DMF, kinetically controlled structures are initially observed, however, mixing occurs at a faster rate and assembled star polymers show a decrease in polydispersity index (PDI) over time. In addition, Bis-DeAP functionalized PS and PMMA were mixed in DMF to generate a star copolymer through self-assembly. (C) 2008 Elsevier Ltd. All rights reserved.