Stabilization of Reactive Organometallic Intermediates Inside a Self‐Assembled Nanoscale Host

Trapped in a cage: A supramolecular metal–ligand assembly is utilized to stabilize two reactive organometallic intermediates in aqueous solution. While these organometallic complexes decompose in organic solution within hours and in the presence of water within minutes, binding into the supramolecular cage renders them inert for several weeks. Despite their stabilization, the guest molecules are still able to react stoichiometrically with CO.