Guest Inclusion and Structural Dynamics in 2-D Hydrogen-Bonded Metal-Organic Frameworks

The structures and dynamic solid-state behavior of four hydrogen-bonded layered metal-organic frameworks are discussed. Three of the complexes incorporate acetone guest molecules between layers; this is attributed to added flexibility in a framework ammonium component. One complex incorporates water guests, in this case an additional -CH2OH arm present on the ammonium component accounting for the difference in guest and dynamic behavior. In all four complexes, TGA and XRD show loss and reuptake of water ligands. In the fourth complex, loss of both water guests and water ligands is reversible, with concomitant loss and regeneration of the crystalline structure. This framework flexibility during guest and ligand loss is unprecedented for hydrogen-bonded metal-organic frameworks.