Fast carbonyl exchange in the solid state for β-cyclodextrin/(arene)Cr(CO)3 inclusion complexes

The exchange of carbonyls is a common feature for metal carbonyl compounds in solution whereas in the solid state high interatomic potential energy barriers cause this occurrence to be highly unlikely; it is shown that the compartmentalization of (arene)Cr(CO)3 in the β-cyclodextrin cavity removes any constraint and thereby facilitates the rotation of the Cr(CO)3 group in the solid state.