New heterometallic frameworks with flexible sulfonate-carboxylate ligand: syntheses, structures, and properties

Solvothermal reactions of zinc acetate, sodium hydroxide, and sulfosuccinic acid (H3SSC) in alcohol/H2O, afforded two new three-dimensional (3D) heterometallic sulfonate-carboxylate frameworks, namely, [Na2Zn3(mu(3)-OH)(2)(SSC)(2)(H2O)(4)](n) (1) and [Na4Zn(SSC)(2)(H2O)(3.5)](n) (2). Compound 1 contains 2D anionic [Zn-3(mu(3)-OH)(2)(SSC)(2)](2-) layers based on the centrosymmetric mononuclear [Zn(SSC)(2)](4-) units, while compound 2 has 2D anionic [NaZn(SSC)(2)](3-) layers based on the [Zn-2(SSC)(2)] macrocycle units. In both compounds, the 2D anionic layers are linked by sodium ions in various manners to generate quite different 3D architectures. Compounds 1 and 2 exhibit violet photoluminescences in the solid state. In addition, IR spectra, powder X-ray diffraction, elemental analysis, and thermogravimetric analysis of compounds 1 and 2 are also investigated.