Microporous metal-organic framework constructed from heptanuclear zinc carboxylate secondary building units

Abstract

A novel, three-dimensional, noninterpenetrating microporous metal-organic framework (MOF), [Zn7O2(pda)5(H 2O)2]·5 DMF·4 EtOH· 6H2O (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. Zn 7O4(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 A. 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. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.