Complexation of terpyridine-containing dextrans: toward water-soluble supramolecular structures.

Dextran was functionalized with 6-(2,2':6',2″-terpyridin-4'-yloxy)-hexanoic acid using two different ratios of terpyridine to dextran, leading to terpyridine-functionalized dextran esters possessing different degrees of substitution (DS = 0.23-0.41). The intra- and intermolecular complexation behavior of both functionalized biopolymers was studied using Fe(II) metal ions as well as activated Ru(III) complexes. The complexation behavior in the first case was studied by UV-visible and viscosity titration experiments. In the latter case, a water soluble comb-polymer could be obtained when using a PEG- functionalized terpyridine Ru(II) moiety for complexation. Moreover, nanoprecipitation was applied to self-assemble the functionalized dextrans into nanoparticles.