From Local Control to Collective Response: Fabrication of Responsive Organometallic Crystalline Materials by Careful Design of Functionalities and Tailoring of the Intermolecular Interactions

The two aminobenzoic acid isomers 4-amino-3-hydroxybenzoic acid and 3-amino-4-hydroxybenzoic acid have been used to synthesize the corresponding half-sandwich Ru(II) complexes [(p-cymene)Ru(kappa N-ligand)X-2] (X = Cl, I). The solid state structures of all the complexes have been elucidated by single-crystal X-ray analysis. In all the cases, the complexes give rise to wheel-and-axle shaped supramolecular entities based on the dimerization of the carboxylic functionalities, with extended hydrogen bond networks involving the NH2, OH, and X groups. The nature of the halogen ligand strongly influences the host- guest properties of the crystalline materials. In fact, the chloride complexes crystallize as nonsolvates and result as inert toward the uptake of volatile organic compounds. Diversely, the replacement of Cl with I gives rise to systems with remarkable efficiency in exchanging volatile guests (acetone) by fast and reversible solid vapor processes based on the breaking and reforming of hydrogen bonds.