Modular synthesis of poly(perylene bisimides) using click chemistry: a comparative study

A systematic study of the influence of the chemical substitution pattern of side chain polymers carrying perylene bisimide (PBI) pendants is presented. To achieve a high comparability, the modular approach of copper-catalyzed azide-alkyne cycloaddition (CuAAC, click chemistry) was chosen to attach six differently substituted PBI azide moieties to a poly(propargyloxystyrene) backbone to obtain poly (perylene bisimides), PPBIs. The N, N' substituted PPBIs differ structurally in two ways. On the one hand, the N-swallow-tail substituent was varied between hydrophilic oligoethyleneglycol and hydrophobic alkyl groups. On the other hand, the length of the N'-alkyl spacer, connecting PBI moiety and polymer backbone, was varied from (CH2)(6) to (CH2)(8) and to (CH2)(11). The polymer analogous reactions between PBI-azides and poly(propargyloxystyrene) were monitored by H-1 NMR and were found to be nearly quantitative in all cases. The resulting PPBIs exhibit M-n around 60 000 g mol(-1) and narrow PDIs of 1.1. Structure-property relationships of all polymers were elucidated by studying their thermal behaviour using DSC and their structural properties with XRD measurements.