title: Intercalation and grafting of benzene derivatives into zinc-aluminum and copper-chromium layered double hydroxide hosts: an XPS monitoring study.
abstract: We report an original strategy to describe, via X-ray photoelectron spectroscopy (XPS) measurements, the interactions between the organic and the mineral sub-systems within a multifunctional hybrid material. A tunable layered double hydroxide (LDH) host system, either a Zn(2)Al- or Cu(2)Cr-hydrotalcite like compound, is modified with the insertion of the organic guest entities, 4-phenol-sulfonate (HBS) or -carboxylate (HBC). The resulting interactions are studied at two levels: after the organic molecules' insertion in the host LDH (ionic exchange between the LDH counter-ions and the organic anions) and after the condensation (grafting) of the organic species onto the mineral layers when thermally treated. For the inserted material, the main XPS results show a stabilization of the organic molecules within the mineral sheets via H bonding as found elsewhere with FTIR study, the mineral matrix being unchanged. The XPS signal of the organic molecules slightly changes with a widening of core peaks, attesting to some local surrounding modifications. When heating up the Zn(2)Al hybrid material, stronger interactions between organic and inorganic systems appeared from around 80 °C with some obvious electronic changes as monitored with the XPS S2p signal of the HBS guest molecules. At the same time, the PXRD pattern clearly shows a decrease of the basal spacing according to a two step contraction process which could be interpreted as a progressive organic molecule condensation onto the inorganic layers via iono-covalent bonds. A copper-chromium LDH is also studied to probe the same kind of interactions with the HBS molecules. The ability of distortion of such mineral material involves a peculiar process of contraction from 40 °C with the immediate and effective anchorage of organic molecules.
authors: IPREM-UMR CNRS 5254, Université de Pau et des Pays de l'Adour, Pau, France.
authors: Solenne
authors: S
authors: Fleutot
authors: Jean-Charles
authors: JC
authors: Dupin
authors: G
authors: G
authors: Renaudin
authors: Hervé
authors: H
authors: Martinez
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D001555:Benzene Derivatives / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D010316:Particle Size; D013053:Spectrophotometry; D013499:Surface Properties; D014965:X-Rays; D015032:Zinc / Q000737:chemistry*
chemical_list: D001555:Benzene Derivatives; D006878:Hydroxides; D002857:Chromium; D003300:Copper; D000535:Aluminum; D015032:Zinc