Poly[[diaqua(μ2-1,4-dioxane-κ2 O:O′)(μ2-2,3,5,6-tetrafluorobenzene-1,4-dicarboxylato-κ2 O 1:O 4)copper(II)] 1,4-dioxane disolvate dihydrate]

In the title complex, {[Cu(C8F4O4)(C4H8O2)(H2O)2]·2C4H8O2·2H2O}n, the CuII ion is six-coordinated by two oxygen donors from two trans 2,3,5,6-tetrafluoro-1,4-dicarboxylate (BDC-F4) ligands, two O atoms from two chair 1,4-dioxane ligands and two O atoms from two terminal water molecules, adopting a distorted octahedral coordinated geometry. Each BDC-F4 anion bridges two CuII ions in a bis-monodentate fashion, forming a [Cu(BDC-F4)]n chain. These chains are further linked by bridging 1,4-dioxane ligands, generating a two-dimensional net with approximately rectangular grids of 11.253 × 7.654 Å. Such adjacent parallel layers are connected by O—H⋯O hydrogen bonds between guest water molecules and the uncoordinated carboxylate O atoms and coordinated water molecules into the final three-dimensional supramolecular network.

In the title complex, {[Cu(C 8 F 4 O 4 )(C 4 H 8 O 2 )(H 2 O) 2 ]Á-2C 4 H 8 O 2 Á2H 2 O} n , the Cu II ion is six-coordinated by two oxygen donors from two trans 2,3,5,6-tetrafluoro-1,4dicarboxylate (BDC-F 4 ) ligands, two O atoms from two chair 1,4-dioxane ligands and two O atoms from two terminal water molecules, adopting a distorted octahedral coordinated geometry. Each BDC-F 4 anion bridges two Cu II ions in a bis-monodentate fashion, forming a [Cu(BDC-F 4 )] n chain. These chains are further linked by bridging 1,4-dioxane ligands, generating a two-dimensional net with approximately rectangular grids of 11.253 Â 7.654 Å . Such adjacent parallel layers are connected by O-HÁ Á ÁO hydrogen bonds between guest water molecules and the uncoordinated carboxylate O atoms and coordinated water molecules into the final threedimensional supramolecular network.

Related literature
For the solvent template effect of 1,4-dioxane in the construction of coordination polymers, see: Chen et al. (2008); He et al. (2009).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: JJ2078).

Comment
Recently, our group has been engaged in studying the influence that a range of solvent species have on the structures of a series of Mn II -BDC-Cl 4 polymers with 2,3,5,6-tetracholorobenzene-1,4-dicarboxylate (BDC-Cl 4 ) ligand (Chen et al., 2008;He et al.., 2009). Among them, the 1,4-dioxane (dioxane) solvent molecule may serve as a solvent template to play a key role in controlling the resulting polymeric network. To further understand the solvent template effect of 1,4-dioxane, we employed the tetrafluorinated benzene-1,4-dicarboxylic acid (H 2 BDC-F 4 ) ligand to assemble with a copper(II) ion in the presence of dioxane and obtained the title two-dimensional coordination polymer {[Cu(BDC- The asymmetric unit of (I) is composed of one Cu II center, one 2,3,5,6-tetrafluoro-1,4-dicarboxylate (BDC-F 4 ) anion, one dioxane ligand, two coordinated water molecules, and two lattice dioxane as well as two water moieties ( Fig. 1). Each Cu II ion is six-coordinated by two oxygen donors from two trans 2,3,5,6-tetrafluoro-1,4-dicarboxylate (BDC-F 4 ) ligands, two oxygen atoms from two chair dioxane ligands, and two oxygen atoms from two terminal water molecules, adopting a distorted octahedral coordinated geometry. Each BDC-F 4 anion bridges two Cu II ions in a bis-monodentate fashion to form a one-dimensional [Cu(BDC-F 4 )] n chain, which is further joined together by bridging dioxane ligands to generate a two-dimensional net with approximately rectangular grids of 11.253 Å × 7.654 Å (Cu···Cu nucleus-to-nucleus), where the Cu···Cu···Cu angles are 90.8 and 89.2°, respectively (Fig. 2). Such adjacent parallel layers are connected by O-H···O hydrogen bonds between guest water molecules with the uncoordinated carboxylate oxygen atoms and coordinated water molecules to fulfill the final three-dimensional supramolecular network.

Experimental
An aqueous solution (2 ml) of Cu(ClO 4 ) 2 .6H 2 O (37.1 mg, 0.10 mmol) was added to a dioxane solution (4 ml) of H 2 BDC-F 4 (23.8 mg, 0.10 mmol) with stirring for 15 min. Then, the reaction mixture was filtered and left to stand at room temperature.
After 3 days, well blue block crystals of the title compound suitable for X-ray diffraction were obtained by slow evaporation of the solvents in 52% yield (33.1 mg, based on H 2 BDC-F 4 ).

Refinement
All H atoms bound to C atoms were assigned to calculated positions with C-H = 0.97 Å, and refined using a riding model,