Interlayer Surface Modification of the Protonated Triple-Layered Perovskite HCa2Nb3O10·xH2O with n-Alcohols

Seiichi Tahara, Yoshiyuki Sugahara

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Abstract

Organic derivatives of the protonated triple-layered perovskite HCa 2Nb3O10·xH2O with n-alkoxyl groups on the interlayer surface have been prepared by grafting n-alcohols. Interlayer surface modification of HCa2Nb3O 10·xH2O is achieved by a direct reaction of HCa2Nb3O10·xH2O with methanol or ethanol, and single-phase n-alkoxyl derivatives of HCa 2Nb3O10·xH2O (n ≥ 3 in n-CnH2n+1O- groups) can be formed by reacting n-alkoxyl derivatives (methoxyl and n-propoxyl derivatives) with n- alcohols in an autoclave at 150 °C. X-ray diffraction analysis shows the changes in interlayer distances upon treatment of HCa2- Nb3O 10·xH2O or intermediate n- alkoxyl derivatives with n-alcohols. Solid-state 13C CP/MAS (cross polarization and magic-angle spinning) NMR spectroscopy demonstrates the presence of signals due to n-alkoxyl groups originating from the reactant n-alcohol molecules. Differential thermal analysis curves of the products exhibit exothermic peaks at temperatures higher than 200 °C. These results indicate successful preparation of HCa2Nb3O10 derivatives possessing various n-alkoxyl groups (n-CnH2n+1O-, n = 1-4, 6, 8, 10, 12, 14, 16, and 18) on the interlayer surface. Although a reaction between an n-propoxyl derivative and n-decanol does not proceed at 80 °C, a single-phase n- decoxyl derivative can be obtained at 80 °C by adding a small amount of water (1 mass %), which strongly suggests a hydrolysis-esterification mechanism, IR and solid-state 13C CP/MAS NMR spectroscopies indicate that the n-alkyl chains in n-alkoxyl derivatives (n ≥ 10 in n-CnH2+1O- groups) possess an all-trans conformation. A linear relationship with a slope of 0.166 nm/carbon atom is observed between the interlayer distance and the number of carbon atoms in the n-alkyl chains, suggesting that the n-alkyl chains of n-alkoxyl groups are present as bilayers with a tilt angle of 41° in the interlayer space.

Original languageEnglish
Pages (from-to)9473-9478
Number of pages6
JournalLangmuir
Volume19
Issue number22
DOIs
Publication statusPublished - 2003 Oct 28

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ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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