High-Molecular-Weight Poly[2]catenanes Prepared by Hydroxyl-Alkyne Click Chemistry

Abstract

Due to the combination of flexibility and mobility, polycatenanes have the potential in constructing various functional materials. To date, most of the previous works have reported poly[2]catenanes with a degree of polymerization (DP) of around 20. However, it remains a significant challenge to synthesize poly[2]catenanes with a higher DP value. Hydroxyl−yne click polymerization, bearing the merits of obtaining polymers with high DP values, short reaction time, and mild condition, is promising to be employed in preparing poly[2]catenanes with high DP values. Herein, a strategy using hydroxyl−yne click chemistry to fabricate poly[2]catenanes was proposed. With two hydroxyl groups on both the rings, [2]catenane monomer M1 was prepared. Meanwhile, hexaethylene glycol was alkyne functionalized as M2. With bicyclo[2.2.2]-1,4-diazaoctane (DABCO) catalyzing, M1 and M2 reacted via a hydroxyl−yne click reaction at room temperature. The DP of resultant poly[2]catenane reached up to 36. In addition, tetraphenylethylene (TPE) was modified with propiolic acid to obtain M3. Then, poly([2]catenane-alt-TPE) with aggregation-induced emission (AIE) properties was obtained via the polymerization between M1 and M3 as well.