Argentivorous molecules: structural evidence for Ag(+)-π interactions in solution.

Tetra-armed cyclens bearing aromatic side arms were prepared by the reductive amination of cyclen with substituted benzaldehydes. When equimolar amounts of Ag(+) ions were added to the ligands, the aromatic rings covered the Ag(+) ions incorporated in the ligand cavities, as if the aromatic ring "petals" caught the Ag(+) ions in the way an insectivorous plant (Venus flytrap) catches insects. The ligands are called "argentivorous molecules". Evidence of intramolecular Ag(+)-π interactions in solution and in the solid state is reported.