Synthesis of poly[2]catenane having rigid linkage by 1,3-dipolar cycloaddition of diazido[2]catenane with 4,4′-diethynylbiphenyl

A novel poly[2]catenane having rigid triazole rings between [2]catenane moieties was synthesized by the 1,3-dipolar cycloaddition of diazido[2]catenane with 4,4′-diethynylbiphenyl. The reaction proceeded effectively under mild conditions and gave a polymer in high yield. The number average molecular weight (Mn) of the polymers was 1.5 × 104-2.5 × 104. A cyclic dimer consisting of two [2]catenane moieties and two biphenylene units was formed along with the polymer. The cyclodimerization was suppressed by performing the reaction at a low temperature without lowering the yield or molecular weight of the polymer. The novel poly[2]catenane had higher solubility in some solvents than the corresponding non-catenated polymer having a similar primary structure.