Formation of Self-Templated 2,6-Bis(1,2,3-triazol-4-yl)pyridine [2]Catenanes by Triazolyl Hydrogen Bonding: Selective Anion Hosts for Phosphate.

We report the remarkable ability of 2,6-bis(1,2,3-triazol-4-yl)pyridine (btp) compounds 2 with appended olefin amide arms to self-template the formation of interlocked [2]catenane structures 3 in up to 50 % yield when subjected to olefin ring-closing metathesis in CH2 Cl2 . X-ray diffraction crystallography enabled the structural characterization of both the [2]catenane 3 a and the non-interlocked macrocycle 4 a. These [2]catenanes showed selective triazolyl hydrogen-bonding interactions with the tetrahedral phosphate anion when screened against a range of ions; 3 a,b are the first examples of selective [2]catenane hosts for phosphate.