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

摘要

A novel,three-dimensional,noninterpenetrating microporous metal-organic framework(MOF),[Zn_7O_2(pda)_5(H_2O)_2]centre dot 5 DMF centre dot 4 EtOH centre dot 6H_2O(1)(H_2PDA=p-phenylenedi-acrylic acid,DMF=N,N-dimethylform-amide,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 heptametal-lic SBU,Zn_7O_4(CO_2)_(10),with dimensions of 9.8 X 9.8 X 13.8 A~3.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 H_2O and CH_3OH,and substantial H_2 uptake.In terms of the heptanuclear zinc carboxylate SBUs,polymer 1 exhibits interesting photo-electronic properties,which would facilitate the exploration of new types of semiconducting materials,especially among MOFs containing multinuclear metal carboxylate SBUs.