Responsive backbones based on alternating triazole-pyridine/benzene copolymers: From helically folding polymers to metallosupramolecularly crosslinked gels

Step-growth polymerization using Cu-catalyzed 1,3-dipolar cycloaddition reactions, commonly referred to as "click chemistry," has been used to prepare poly[(1,2,3-triazol-4-yl-1,3-pyridine)-alt-(1,2,3-triazol-1-yl-1,3-phenylene)]s. The recently discovered strong preference of the 2,6-bis(1,2,3-triazol-4-yl)pyridine (BTP) subunits to adopt an anti-anti conformation enables the extended heteroaromatic polymer strands to adopt a helical conformation, as shown by circular dichroism (CD) spectroscopy. Addition of various transition metal ions leads to coordinative crosslinking and therefore efficient gelation of the polymer solutions. The integration of the BTP scaffold in the main chain of the described polymers illustrates a synthetically inspired approach to readily access new functional macromolecules with potential applications as sensing and magnetic/emissive materials.