A one-dimensional coordination polymer with a three-dimensional supramolecular framework: catena-poly[[[(3,4,7,8-tetramethyl-1,10-phenanthroline) cadmium(II)]-μ3-4,4′-sulfonyldibenzoato] trihydrate]

In the title mixed-ligand metal-organic polymeric compound, {[Cd(C14H8O6S)(C16H16N2)]center dot 3H2O}(n), the asymmetric unit contains a crystallographically unique Cd-II atom, one doubly deprotonated 4,4'-sulfonyldibenzoic acid (H(2)SDBA) ligand, one 3,4,7,8-tetramethyl-1,10-phenanthroline (TMPHEN) molecule and three solvent water molecules. Each Cd-II centre is six-coordinated by two O atoms from a chelating carboxylate group of a SDBA(2-) ligand, two O atoms from monodentate carboxylate groups of two different SDBA(2-) ligands and two N atoms from a chelating TMPHEN ligand. There are two coordination patterns for the carboxylate groups of the SDBA(2-) ligand, with one in a mu(1)-eta(1):eta(1) chelating mode and the other in a mu(2)-eta(1):eta(1) bis-monodentate mode. Single-crystal X-ray diffraction analysis revealed that the title compound is a one-dimensional double-chain polymer containing 28-membered rings based on the [Cd-2(CO2)(2)] rhomboid subunit. More interestingly, a chair-shaped water hexamer cluster is observed in the compound.