Isoreticular Synthesis of Mesoporous Metal-Organic Polyhedra with Permanent Porosity to Gas and Water

Synthesis of mesoporous metal-organic cages or polyhedra (MOCs or MOPs) that retain their porous functionality in the solid-state remains challenging, given their tendency to collapse upon desolvation. Herein, we report the use of the isoreticular expansion approach to synthesize two permanently porous Rh(II)-based octahedral MOPs within the mesoporous regime. Our mesoporous MOPs, featuring internal cavities of up to 12.5 nm³, withstand the activation process, enabling their use as solid-state adsorbents for gases and water. In particular, the largest mesoporous MOP, named BCN-17, captures up to 0.47 g_water·g_MOP ^-1 and exhibits an S-shaped water-sorption isotherm with a hysteresis loop, characteristic of mesoporous materials.