Microporous Metal-Organic Framework Constructed from Heptanuclear Zinc Carboxylate Secondary Building Units

A novel, three‐dimensional, noninterpenetrating microporous metal–organic framework (MOF), [Zn7O2(pda)5(H2O)2]⋅5 DMF⋅4 EtOH⋅ 6 H2O (1) (H2PDA=p‐phenylenediacrylic acid, DMF=N,N‐dimethylformamide, EtOH=ethanol), was synthesized by constructing heptanuclear zinc carboxylate secondary building units (SBUs) and by using rigid and linear aromatic carboxylate ligands, PDA. The X‐ray crystallographic data reveals that the seven zinc centers of 1 are held together with ten carboxylate groups of the PDA ligands and four water molecules to form a heptametallic SBU, Zn7O4(CO2)10, with dimensions of 9.8×9.8×13.8 Å3. Furthermore, the heptametallic SBUs are interconnected by PDA acting as linkers, thereby generating an extended network with a three‐dimensional, noninterpenetrating, intersecting large‐channel system with spacing of about 17.3 Å. As a microporous framework, polymer 1 shows adsorption behavior that is favorable towards H2O and CH3OH, and substantial H2 uptake. In terms of the heptanuclear zinc carboxylate SBUs, polymer 1 exhibits interesting photoelectronic properties, which would facilitate the exploration of new types of semiconducting materials, especially among MOFs containing multinuclear metal carboxylate SBUs. In the frame: A three‐dimensional metal–organic framework with non‐interpenetrating, intersecting large channels (see picture) was synthesized by constructing heptanuclear zinc–carboxylate secondary building units and by using rigid and linear aromatic carboxylate ligands. The polymer shows adsorption behavior favorable towards H2O and CH3OH, and substantial H2 uptake, as well as interesting photoelectronic properties.