Noncovalent Trapping and Stabilization of Dinuclear Ruthenium Complexes within a Coordination Cage

A dinuclear ruthenium complex, [(η⁵-indenyl)Ru(CO)₂]₂, was noncovalently enclathrated within a self-assembled coordination cage. In the cavity, rapid cis–trans isomerization and ligand exchange between the terminal and bridging carbonyls were suppressed, and only the carbonyl-bridged cis configuration was observed by X-ray crystallographic analysis.