Two-dimensional metal-organic frameworks containing linear dicarboxylates.

The solvothermal synthesis of four two-dimensional metal-organic frameworks containing linear dicarboxylic acids as ligands for Zn(II) centres is described. Zn(BDC)(DMF) [(1) where BDC = benzene-1,4-dicarboxylic acid; DMF = N,N-dimethylformamide] adopts a common paddlewheel motif leading to a 4(4) grid network, whereas Zn(3)(BDC)(3)(EtOH)(2) (2), Zn(3)(BDC)(3)(H(2)O)(2) * 4DMF (3) and Zn(3)(BPDC)(3)(DMF)(2) * 4DMF (4) each form networks with the relatively uncommon 3(6) topology based upon Zn(3)(O(2)CR)(6) secondary building units. All contain coordinated solvent molecules, namely DMF [(1) and (4)], ethanol (2) or H(2)O (3). Comparison of structures (2) and (3) illustrates a clay-like flexibility in interplanar spacing which sheds light on the ability of the Zn(3)(BDC)(3) framework to undergo desolvation and uptake of small solvent and gas molecules.