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Author Tronto, Jairo ♦ Pinto, Frederico G. ♦ Costa, Liovando M. da ♦ Leroux, Fabrice ♦ Dubois, Marc ♦ Valim, João B.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ ACETATES ♦ ALUMINIUM 27 ♦ CARBON 13 ♦ CATIONS ♦ CLATHRATES ♦ ELECTRON SPIN RESONANCE ♦ ELECTRONS ♦ EMISSION SPECTROSCOPY ♦ FOURIER TRANSFORM SPECTROMETERS ♦ FOURIER TRANSFORMATION ♦ HEAT TREATMENTS ♦ HYDROXIDES ♦ NUCLEAR MAGNETIC RESONANCE ♦ POLYCYCLIC SULFUR HETEROCYCLES ♦ POLYMERIZATION ♦ SCANNING ELECTRON MICROSCOPY ♦ THERMAL GRAVIMETRIC ANALYSIS ♦ THIOPHENE ♦ TRANSMISSION ELECTRON MICROSCOPY ♦ X-RAY DIFFRACTION
Abstract A layered double hydroxide (LDH) with cation composition Zn{sub 2}Al was intercalated with 2-(thiophen-3-yl)acetate (3-TA) monomers. To achieve in situ polymerization and/or oligomerization of the intercalated monomers, soft thermal treatments were carried out, and subsequent hybrid LDH materials were analyzed by means of several characterization techniques using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), {sup 13}C CP–MAS nuclear magnetic resonance (NMR), electron spin resonance (EPR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), inductively coupled plasma optical emission spectroscopy (ICP–OES), and elemental analysis. PXRD analysis suggested that the intercalated monomers formed a bilayer. Thermal treatment of the hybrid LDH assembly above 120 °C provokes partially the breakdown of the layered structure, generating the phase zincite. EPR results indicated that vicinal monomers (oligomerization) were bound to each other after hydrothermal or thermal treatment, leading to a polaron response characteristic of electron conductivity localized on a restricted number of thiophene-based monomer segments. Localized unpaired electrons exist in the material and interact with the {sup 27}Al nuclei of the LDH layers by superhyperfine coupling. These unpaired electrons also interact with the surface of ZnO (O{sup 2−} vacancies), formed during the thermal treatments. - Graphical abstract: We synthesized a layered double hydroxide (LDH) with cation composition Zn{sub 2}Al, intercalated with 2-(thiophen-3-yl)acetate (3-TA) monomers, by coprecipitation at constant pH. We thermally treated the material, to achieve in situ polymerization and/or oligomerization of the intercalated monomers. - Highlights: • A Zn{sub 2}Al–LDH was intercalated with 2-(thiophen-3-yl)acetate monomers. • To achieve in situ oligomerization of the monomers, thermal treatments were made. • Thermal treatment above 120 °C causes partially breakdown of the LDH structure. • ESR results indicated a polaron response characteristic of electron conductivity.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-01-15
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 221


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