Unexchangeable Interlayer Anions:Synthesis and Characterization of Zn/Al- and Mg/Al-Layered Double Hydroxides with Interlayer Alizarin red S

摘要

Zn/Al- and Mg/Al-layered double hydroxides with interlayer 9.10-anthraquinone-1,2-dihydroxy-3-sulfonate (Alizarin red S anion abbreviated as ARS) are synthesized (products are abbreviated as M/Al/ARS-LDH where M=Mg or Zn) and the solid-state properties are characterized.In powder X-ray diffraction measurements,basal spacings of the layered compounds are elucidated on the basis of the molecular size of ARS and its conformation at the interlaver gallery regon.~27Al MAS NMR spectra reveal that the Al~(3+) ions in the layers of Zn/Al/ARS-LDH or Mg/Al/ARS-LDH locate in the synthesis of Zn/Al/ARS-LDH,locate in the penta- or the tetra-coordination sphere.FT-IR spectra and ~13C CP/MAS NMR spectra illustrate that the interlayer ARS anions are stable in both layered compounds and the coordination bond is formed in Zn/Al/ARS-LDH between the sulfonate of ARS and Al~(3+) in the layer.The interlayer ARS anions are not eliminated from the interlayer region of Zn/Al/ARS-LDH when the solid is immersed in an aqueous solution containing carbonate;the unexchangeable nature of the interlayer ARS with carbonate results from the coordination bond observed in FT-IR and ~13C CP/MAS spectra.