Control of Channel Size for Selective Guest Inclusion with Inlaid Anionic Building Blocks in a Porous Cationic Metal-Organic Host Framework

Through the introduction of perfluorocarboxylates its counteranions that line the inner surface of each channel in a host cationic metal-organic open framework. stepwise channel-size control has been realized, resulting in wide guest compatibility for [{Ag(L)(CF(3)CO(2))}(6)center dot 6G](infinity) (1 superset of G; G=guest, L=ligand), selective guest recognition for [{Ag(L)(C(2)F(5)CO(2))(6)center dot 4G'](infinity) (2 superset of G'), and a lack of inclusion behavior for [{Ag(L)(C(3)F(7)CO(2))}(6)](infinity) (3; G and G' represent the same or different guest molecules). The cationic frameworks in 1-3 are constructed from the linkage of hexameric inorganic-organic hybrid macrocycles through multiple argentophilic interaction plus pi-pi interactions between pyridyl rings and carbonyl-carbonyl interactions, to which corresponding counteranions are attached. With different anions as intrachannel arms, similar frameworks in complexes 1 superset of G, 2 superset of G', and 3 exhibit percentages of guest-accessible voids of approximately 30-35, 25, and 18% for 1-3, respectively. The highly flexible framework 1 in 1 superset of G contains stretchable channels with up to 21.7% effective-volume change of the solvent-accessible void for inclusion of various guest species in the series of solvates la-m. The pair of complexes 1 superset of G and [Ag(L)(CF(3)CO(2))](infinity) (4), and likewise the pair 2 superset of G' and [Ag(L)(C(2)F(5)CO(2))](infinity) (5), are interconvertible through distinct controllable processes.