Hybrid Single-Crystalline Mesoporous Frameworks Merging Metal-Organic and Hydrogen-Bonded Organic Networks

Mesoporous materials represent an important class of porous materials; however, it remains a great challenge to systematically synthesize hybrid single-crystalline mesoporous frameworks merging metal-organic and hydrogen-bonded organic networks. Herein, we report a hybrid merged-net strategy that integrates a supramolecular hydrogen-bonded organic network with a single-crystalline mesoporous metal-organic framework (MOF), significantly enhancing structural robustness without sacrificing intrinsic mesoporosity. The assembly of pyridine-containing carboxylate linkers and iron-containing trinuclear clusters affords M-PPB featuring the (6,6)-connected 6²T44 net, in which directional O─H⋯N hydrogen bonds between adjacent linkers form a one-dimensional hydrogen-bonded network. In contrast to the unstable parent (4,6)-connected stp-MOF, M-PPB-merging metal-organic and hydrogen-bonded organic networks-exhibits enhanced robustness and achieves full porosity, displaying a pore volume of 1.58 cm³ g^{- 1}. We further apply an isoreticular expansion strategy to synthesize extended MOFs-M-PPPB-containing mesopores of about 4.2 nm and exhibiting a pore volume of up to 2.77 cm³ g^{- 1}. On account of its ultrahigh porosity, M-PPPB exhibits a methane uptake of 1.047 g g^{- 1} at 159 K and 10 bar, nearly twice that of M-PPB, while its hydrogen uptake at 77 K and 100 bar increases by about 50%.