Closing the Loop: Triazolylpyridine Coordination Drives the Self-Assembly of Metallomacrocycles with Tunable Topologies for Small-Molecule and Guanine-Quadruplex Recognition.

The 2-(1,2,3-triazol-4-yl)pyridine motif, with its facile "click" synthesis and remarkable coordinative properties, is an attractive chelate for applications in the metal-directed self-assembly of intricate three-dimensional structures. Organic ligands that bear two such chelates bridged by flexible hinge moieties readily undergo self-assembly with metal ions of different coordination geometries to generate a series of topologically diverse metallomacrocycles that can be used for numerous applications. Herein, the synthesis and self-assembly of one such ligand with zinc(II), copper(II), and palladium(II) ions is reported, and the stability of the resulting metallomacrocycles described. An investigation into the use of these metallomacrocycles for the recognition of both small-molecule substrates, such as deoxyguanosine monophosphate, and larger biological assemblies, such as DNA and RNA guanine quadruplexes, is also described.