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 1H NMR and were found to be nearly quantitative in all cases. The resulting PPBIs exhibit Mn 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.