In situ oligomerization of 2-(thiophen-3-yl)acetate intercalated into Zn sub(2)Al layered double hydroxide

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 we...

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Bibliographic Details
Published in:Journal of solid state chemistry 2015-01, Vol.221, p.391-397
Main Authors: Tronto, Jairo, Pinto, Frederico G, da Costa, Liovando M, Leroux, Fabrice, Dubois, Marc, Valim, Joao B
Format: Article
Language:English
Subjects:
Cations
Coprecipitation
Fourier transforms
Hydroxides
Infrared spectroscopy
Monomers
Nuclear magnetic resonance
Oligomerization
Polymerization
Scanning electron microscopy
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Summary: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), super(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 degree 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 super(27)Al nuclei of the LDH layers by superhyperfine coupling. These unpaired electrons also interact with the surface of ZnO (O super(2-) vacancies), formed during the thermal treatments. 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.
ISSN:0022-4596
DOI:10.1016/j.jssc.2014.10.030