Pillarplexes: A Metal–Organic Class of Supramolecular Hosts

Novel octanuclear NHC complexes of
gold­(I) and silver­(I) form metallocavitand
structures with very defined tubular cavities and are able to selectively
host linear molecules, exemplarily demonstrating 1,8‑diaminooctane as a model
guest molecule. The solubility of the host-compounds
is easily adjusted by simple anion exchange reactions so that the
compounds can be made soluble in water wherein they exhibit a high
longtime stability. The gold­(I) complex is emissive in aqueous solutions,
which enables a determination of the binding constant to the diamine
via luminescence quenching. The host–guest interaction was
further investigated by isothermal titration calorimetry, NMR spectroscopy,
and X-ray crystallography.