Reversible Single Crystal to Single Crystal Transformation through Fe−O(H)Me/Fe−OH₂ Bond Formation/Bond Breaking in a Gas−Solid Reaction at an Ambient Condition

A single crystal of an iron compound containing a Fe−OH2 bond, on exposure to methanol vapor at an ambient condition, transforms to another single crystal with the formation of a Fe−O(H)Me covalent bond at the cost of breaking the Fe−OH2 bond. The methanol complex, upon exposure to atmospheric water vapor at room temperature, goes back to an original water-coordinated complex. The full reversibility of this gas−solid system was established by X-ray crystallography and IR spectroscopy.