Layered solids based on second-sphere coordination interactions: synthesis, spectroscopic characterization, crystal structure and packing of two copper(II) naphthalene-2-sulfonates

[Cu(H2O)6](C10H7SO3)2 1 was obtained from reaction of CuCO3$Cu(OH)2 and naphthalene-2-sulphonic acid in aqueous medium in 1:4 molar ratio. It crystallizes in the monoclinic space group P21/n with aZ7.0582(3) A ° , bZ6.2666(3) A ° , and cZ27.1420(10) A ° , bZ 92.678(4)8, ZZ2. The structure was determined from 1986 observed reflections and refined to RZ0.033. When ethylenediamine was added to hexaaquacopper(II) naphthalene-2-sulfonate dissolved in water, [Cu(en)2(H2O)2](C10H7SO3)2 2 was obtained which crystallizes in the triclinic space group P 1 with aZ7.1491(5) A ° , bZ7.1949(5) A ° , and cZ14.6500(10) A ° , aZ99.025(6)8, bZ98.976(6)8, and gZ104.262(6)8, ZZ1. The structure was determined from 2296 observed reflections and refined to RZ0.0313. X-ray structure determination of 1 revealed an ionic structure consisting of [Cu(H2O)6]C2 and two naphthalene-2-sulfonate anions while that of 2 contains [Cu(en)2(H2O)2]2C cation and two naphthalene-2-sulfonate anions. Characteristic for the studied crystals is the alternated-layer arrangement of complex cations and naphthalene-2-sulfonate anions, linked together via hydrogen bonding, and the presence of a particularly robust R22 ð8Þ hydrogen-bonding motif that joins the complex cation with two oxygen atoms of the same sulfonate group. Elemental analyses, IR, UV/vis spectroscopic studies are consistent with the structures revealed by X-ray structure determination. q 2005 Published by Elsevier B.V.