Eu3+- and Tb3+-Dipicolinate Complexes Covalently Grafted into Kaolinite as Luminescence-Functionalized Clay Hybrid Materials

Autor(es)

de Araujo, Denis Talarico ; Ciuffi, Katia J. ; Nassar, Eduardo J. ; Vicente, Miguel A. ; Trujillano, Raquel ; Calefi, Paulo S. ; Rives, Vicente ; de Faria, Emerson H.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 121, n. 9, p. 5081-5088, MAR 9 2017.
• Citações Web of Science: 3

Resumo

The luminescence properties of Eu3+- and Tb3+-dipicolinate (pyridine- dicarboxylate) complexes covalently grafted into a kaolinite matrix were studied. The stability of the grafted lanthanide complexes as a function of the thermal treatment was also investigated. Kaolinite intercalated with dimethyl sulfoxide was heated in the presence of melted dipicolinic acid to form dipicolinate-intercalated kaolinite. The luminescent hybrid solids were obtained by complexation of Eu3+ or Tb3+ cations with this intercalated solid at cation/ligand molar ratios of 1:1, 1:2, or 1:3. The resulting materials were characterized by thermal analysis, CHN element analysis, powder X-ray diffraction, infrared absorption spectroscopy, and photoluminescence. The lanthanide complexes covalently grafted into kaolinite were thermally more stable than the isolated lanthanide complexes. The hybrid materials exhibited more intense Eu3+ and Tb3+ emissions than the isolated complexes. The excitation spectra of the hybrid materials showed a broad band at 277 nm, assigned to a ligand-to-metal charge transfer, whereas the emission spectra showed bands related to the typical electronic transitions of Eu3+ and Tb3+ ions from the excited states D-5(0) and D-5(4) to the F-7(j) fundamental states. The (4 -> 5 and 4 -> 4) and (0 -> 2) transitions were the most intense ones and corresponded to green and red emissions, respectively. (AU)

• Processo FAPESP: 13/50216-0 - New clay-based materials with advanced technological and environmental applications
• Beneficiário: Katia Jorge Ciuffi Pires
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/01501-1 - Catalisadores multifuncionais para processos oxidativos avançados empregando matrizes biogênicas ou argilas
• Beneficiário: Katia Jorge Ciuffi Pires
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/19523-3 - Materiais biohíbridos funcionais baseados em argilas lamelares e/ou fibrosas com aplicações multifacetadas
• Beneficiário: Emerson Henrique de Faria
• Modalidade de apoio: Auxílio à Pesquisa - Regular