Synthesis of Pyrene End-Capped A6 Dendrimer and Star Polymer with Phosphazene Core via Click Chemistry''

Abstract

Novel hexa-armed and pyrene (Pyr) end-capped phosphazene dendrimer [N3P3-(Pyr()6)] and star polymer with poly(epsilon-caprolactone) (PCL) arms [N3P3-(PCL-Pyr)(6)] were prepared via two series of reactions. In these series, core-first approach was used starting from a hexa-hydroxy functional phosphazene derivative (N3P3-(OH)(6)). It was used as an initiator in the ring-opening polymerization of epsilon-caprolactone to prepare a hexa-armed PCL star polymer (N3P3-(PCL-OH)(6)). Hydroxyl functionalities of N3P3-(OH)(6) and N3P3-(PCL-OH)(6) were then successfully converted into bromide and azide, in turn. Further end-group modifications of azide functional dendrimer precursor (N3P3-(N-3)(6)) and star polymer (N3P3-(PCL-N-3)(6)) were achieved quantitatively via the Cu(I) catalyzed click reaction between azide functional groups and 1-ethynyl pyrene in the final step. Moreover, the pyrene end-capped phosphazene dendrimer and star polymer were used in noncovalent functionalization of multiwalled carbon nanotubes. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3193-3206, 2011