STRUCTURES OF LAYERED METAL SULFONATE SALTS - TRENDS IN COORDINATION BEHAVIOR OF ALKALI, ALKALINE-EARTH AND TRANSITION-METALS

Several new metal arylsulfonates have been prepared from reactions of metal salts and sodium arylsulfonate salts in aqueous solution. The products have been characterized by single crystal X-ray diffraction techniques. Co(HO(O2N)C6H3SO3)2.6H2O: triclinic, space group P1BAR, Z = 1, a = 6.455(2), b = 15.541(5), c = 5.687(2) angstrom, a = 92.55(3), beta = 94.13(2), gamma = 98.76(2)-degrees, V = 561.4(3)angstrom3, R(F2) = 0.076 for 1979 observations (I > 0) and 160 variables (R(F) = 0.042 for 1274 data with I > 3sigma(I)). The structure contains layers composed of two sheets of 4-hydroxy-3-nitrobenzenesulfonate anions with [Co(H2O)6]2 cations sandwiched in between. There are hydrogen bonds between the coordinated water molecules and sulfonate anions but no direct coordination of the metal by the sulfonate oxygen atoms. Na4(HO(O2N)C6H3SO3)4.2H2O: monoclinic, space group Pc, Z = 2, a = 8.293(3), b = 16.580(2), c = 13.465(2) angstrom, beta = 90.29(2)-degrees, V = 1851.5(8) angstrom3, R(F2) = 0.148 for 3248 observations (I>0) and 229 variables (R(F) = 0.081 for 1747 data with I > 3sigma(I)). The sodium ions are coordinated directly to the oxygen atoms of the 4-hydroxy-3-nitrobenzenesulfonate ions, forming a double sheet of sulfonate anions with cations in between. There are also two water molecules associated with the sodium ions. Ca(H3C(H2N)C6H3SO3)2.7H2O: monoclinic, space group P2(1)/c, Z = 4, a = 14.859(3), b = 6.227(4), c = 25.452(2) angstrom, beta = 101.07(1)-degrees, V = 2311(1) angstrom3, R(F) = 0.059 for 2186 observations (I > 3sigma(I)) and 289 variables. This structure, too, has alternating layers of sulfonate ions and hydrated cations. The calcium ions coordinate directly to one of the sulfonate oxygen atoms and six water molecules in a pentagonal bipyramidal arrangement. The crystal structures of these materials and other recently reported layered metal sulfonates are discussed in relation to apparent trends in the coordination behavior of the metal ions.