A journey from solution to the surface: Expanding the utility of 1,2,3-triazoles in supramolecular chemistry

Since the discovery of the Cu-catalyzed cycloaddition between alkynes and azides ("click" chemistry), the 1,2,3-triazole has seen far reaching applications in drug design, metal sensing and as a general ligation strategy in biochemistry. Apart from its ease of preparation, the polarization imparted by the three electronegative nitrogens of the triazole also generates a strong, neutral C--H hydrogen bond donor capable of interacting with anionic species. With the myriad roles that anions play in our everyday lives, supramolecular chemists are driven to design functional molecules that can monitor and regulate anions across different phases. This lecture will discuss advances made on the C--H···X - interaction within three different contexts: (1) solution phase binding of elliptically shaped macrocycles for linear azides (N 3-) and tetrahedral anions (ClO4 -, ReO4-), (2) creation of anion-responsive self-assembled architectures at two-dimensional surfaces, and (3) synthesis of highly functionalized aryl-triazole monomers in the preparation of anion-binding polymers. The design strategies for each category will be described and highlight how the modularity of the click reaction allows for rapid access to a diverse library of anion binding molecules for a variety of applications.