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

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.