Fullerene and ruthenium dual end-functionalized thermosensitive polymers: synthesis, characterization, electrochemical properties, and self-assembly

Abstract

A general procedure for the synthesis of well-defined fullerene end-functionalized metallopolymers with a metal complex terminal group is described. Several fullerene and tris(bipyridine)ruthenium dual end-functionalized poly(N-isopropylacrylamide) (PNIPAM) metallopolymers were prepared using three successive reactions involving a living radical polymerization, an end-group transformation, and a metal–ligand complexation. Initially, the bipyridine end-fuctionalized PNIPAM polymers were prepared by reversible addition fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide using a bipyridine-functionalized RAFT agent. The terminal groups (Ph–CS–S–) of the RAFT-prepared PNIPAM polymers were transformed into C₆₀ end-groups by their reactions with C₆₀ in the presence of azobisisobutyronitrile (AIBN). The bipyridine end-groups of the fullerene end-functionalized PNIPAM macroligands were finally complexed with ruthenium ions to produce well-defined fullerene and ruthenium dual end-functionalized PNIPAM thermosensitive metallopolymers. The detailed molecular characterization of these products and their precursors confirmed the composition and structure of these new metallopolymers. This modular strategy represents a new, straightforward, and versatile methodology for the preparation of new fullerene-monotelechelic macroligands and metallopolymers.