Post modification of acetylene functional poly(oxindole biphenylylene) by photoinduced CuAAC

Abstract

A novel strategy to obtain side chain modified poly(oxindole biphenylylene) (PDXI) by photoinduced copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction is described. In the first step, an alkyne-functionalized poly(oxindolebiphenylylene) (PDXI-alkyne) is synthesized by superacid-catalyzed condensation of isatin with aromatic hydrocarbons. Subsequently, poly(ethylene glycol) methyl ether (Me-PEG), 1-pyrenemethanol (Py-OH) and 1,3-dibromopropane (DBP) are functionalized by azide groups via simple nucleophilic substitution reaction. Visible-light-induced CuAAC reaction between PDXI-alkyne and the corresponding azide functionalized click components employing dibenzoyldiethylgermane (DBDEG) as photoactivator resulted in the formation of PDXI-PEG, PDXI-Py and insoluble network, respectively. Successful modification of PDXI was confirmed by the spectral, (H-1 NMR, FT-IR, Fluorescence), chromatographic (GPC) and thermal (DSC) investigations.