Two threefold interpenetrated two-dimensional frameworks based on a flexible imidazole-containing ligand and benzene-1,4-dicarboxylate.

The open-chain polyether-bridged flexible ligand 1,2-bis[2-(1H-1,3-imidazol-1-ylmethyl)phenoxy]ethane (L) has been used to create two two-dimensional coordination polymers under hydrothermal reaction of L with Cd(II) or Co(II), in the presence of benzene-1,4-dicarboxylic acid (H(2)bdc). In poly[[(μ(2)-benzene-1,4-dicarboxylato){μ-1,2-bis[2-(1H-1,3-imidazol-1-ylmethyl)phenoxy]ethane}cadmium(II)] dihydrate], {[Cd(C(8)H(4)O(4))(C(22)H(22)N(4)O(2))]·2H(2)O}(n), (I), and the cobalt(II) analogue {[Co(C(8)H(4)O(4))(C(22)H(22)N(4)O(2))]·2H(2)O}(n), (II), the Cd(II) and Co(II) cations are six-coordinated by four carboxylate O atoms from two different bdc(2-) dianions in a chelating mode and two N atoms from two distinct L ligands. The metal ions, bdc(2-) dianions and L ligands each sit across crystallographic twofold axes. The bdc(2-) coordination mode and the coordinating orientation of the L ligand play an important role in constructing the novel two-dimensional framework. Complexes (I) and (II) are threefold interpenetrated two-dimensional frameworks; their structures are almost isomorphous, while the bond lengths, angles and hydrogen bonds are different in (I) and (II).