Fabricating organometallic wheel-and-axle compounds for the creation of dynamically porous crystalline materials.

A family of organometallic compounds has been designed based on half-sandwich ruthenium complexes [(arene)Ru(L)X2] (X = Cl, I); this showed dynamic host–guest properties towards volatile molecules, caused by small local reversible structural rearrangements. These features are derived from the supramolecular organization of the compounds in the solid state, based on a so-called wheel-and-axle pattern, which is known to favour guest inclusion. The molecular features of the Ru complexes (arene size and shape, ligand size and chemical properties, and halogen nature) were screened in order to optimize the final performance of the materials. The design strategy has proven to be successful, affording materials capable of allowing dynamic exchange of volatile molecules by gas–solid processes and solid–solid transformations without loss of crystallinity. [ABSTRACT FROM AUTHOR]