Structural chemistry of naphthalenedisulfonate salts

Salts of naphthalenedisulfonate anions with several different metal cations have been crystallized and their structures determined by single crystal X-ray methods. Crystal data for hexaaquanickel(II) 3-ammonionaphthalene-1,5-disulfonate tetrahydrate, [Ni(H2O)(6)](H3NC10H5(SO3)(2))(2) . 4H(2)O: triclinic, space group P (1) over bar, Z=1, a=12.779(3), b=12.984(4), c=5.473(1) Angstrom, alpha=102.17(2), beta=89.65(2), gamma=114.58(2)degrees, V=803.8(4) Angstrom(3), R(F)=0.038 for 269 variables and 2305 observations (I>3 sigma(I)); disodium 3-aminonaphthalene-1,5-disulfonate pentahydrate, Na-2(H2NC10H5(SO3)2). 5H(2)O: orthorhombic, space group Pbcn, Z=4, a=12.755(4), b=5.890(3), c=23.203(3) Angstrom, V=1743(1) Angstrom(3), R(F)=0.047 for 123 variables and 763 observations (I>3 sigma(I)); bis(6-ammonionaphthalene-1,3-disulfonato)hexaaquabarium tetrahydrate, [Ba(H3NC10H5(SO3)(2))(2)(H2O)(6)].4H2O: monoclinic, space group C2/c, Z=4, a=25.864(3), b=6.874(5), c=21.509(4) Angstrom, beta=116.825(10)degrees, V=3412(2) Angstrom(3), R(F)=0.028 for 274 variables and 2249 observations (I>3 sigma(I)). A cobalt analog of the nickel compound was also prepared and found to be isostructural. All three structures are based on layers of sulfonate anions in which the aromatic rings are cofacial and the SO3- groups are directed to the faces of the layer. The metal ions and water molecules are between these layers and serve to hold them together. Each structure has an extensive hydrogen bonding network. The nickel cation is coordinated octahedrally to six water molecules with no direct coordination to the sulfonate oxygen atoms. The sodium cation is bonded to three sulfonate oxygen atoms and three water molecules in a somewhat distorted octahedron. The barium cation is in an eight-fold coordination of two sulfonate oxygen atoms and six water molecules. The coordination trends and layering patterns of these materials are compared with those of previously reported monosulfonate salts.