STRUCTURAL VARIATIONS IN LAYERED ALKALI-METAL NAPHTHALENESULFONATES

A series of alkali metal and ammonium salts of 6-aminonaphthalene-2-su lfonic acid have been prepared by reaction of the metal hydroxide (or ammonia) and the substituted naphthalenesulfonic acid in water or aque ous ethanol. The structures were determined by single-crystal X-ray di ffraction techniques. Crystal data: K(H2NC10H6SO3). H2O), orthorhombic , Pca2(1), a = 27.139(3) Angstrom, b = 6.172(3) Angstrom, c = 7.135(3) Angstrom, V = 1195(1) Angstrom(3), Z = 4, R(F-o) = 0.039 for 659 obse rvations (I > 3 sigma(I)), 154 variables; Na(H2NC10H6SO3). 2H(2)O, ort horhombic, Pna2(1), a = 11.200(4) Angstrom, b = 7.916(4) Angstrom, c = 26.752(3) Angstrom, V = 2372(2) Angstrom(3), Z = 8, R(F-o) = 0.045 fo r 1813 observation (I > 3 sigma(I)), 325 variables; NH4(H2NC10H6SO3). H2O), orthorhombic, Pbca, a = 12.231(5) Angstrom, b = 26.994(4) Angstr om, c = 7.208(5) Angstrom, V = 2380(2) Angstrom(3), Z = 8, R(F-o) = 0. 056 for 1145 observations (I > 3 sigma(I)), 190 variables. All of the structures contain layers of sulfonate anions in which the long axes o f the naphthalene groups are approximately parallel to the stacking di rection of the layers. The cations lie between the organic layers bond ed to the sulfonate oxygen atoms and one or more water molecules. The structures differ in the detailed packing patterns due to the differen t sizes and coordination behaviors of the cations. The structure of th e monosodium salt of 3-ammonionaphthalene-1,5-disulfonic acid has also been determined: Na(H3NC10H5(SO3)(2)). H2O, triclinic, <P(1)over bar> , a = 10.823(3) Angstrom, b = 12.885(5) Angstrom, c = 5.127(1) Angstro m, alpha = 100.33(3)degrees, beta = 101.65(2)degrees, gamma = 66.19(2) degrees, V = 636.9(4) Angstrom(3), Z = 2, R(F-o) = 0.042 for 1311 obse rvations (I > 3 sigma(I)), 223 variables. The sulfonate anions stack f ace-to-face in infinite columns which are linked into layers by the so dium ions. These layers ae held together by hydrogen bonds between the ammonium and sulfonate groups and between water molecules coordinated to the sodium ions. The structures of these compounds are compared wi th those of previously studied metal sulfonates.