resumo
Novel mixed-metal coordination polymers (CPs) based on Pb1-xEux-BDC (x = 0.05, 0.10, 0.25, 0.50 and BDC = 1,4-benzenedicarboxylic acid) are reported. The materials display different coordination structures as the Pb : Eu metal ratio is modified. Whereas for x < 0.25 the Eu3+ ions essentially replace the Pb2+ ones in the [Pb(BDC)(n)] structure, for x > 0.25 the samples are isotypical with [Eu-2(BDC)(3)(H2O)(4)], as shown by powder (including Rietveld analysis) and single-crystal X-ray diffraction. The unique Pb0.75Eu0.25-BDC compound displays a mixture of both crystalline phases with the highest emission quantum yield value reported for luminescent CPs based on Pb(II), 69 +/- 7%. Site-selective excitation using a common Xe lamp permits the detailed study of the two Eu3+ local sites, illustrating how powerful the Eu3+ luminescence is as a local probe spectroscopic tool.
palavras-chave
WHITE-LIGHT EMISSION; ORGANIC FRAMEWORKS; POWDER DIFFRACTION; 1D CHANNELS; LIGAND; 3D; TEREPHTHALATE; REFINEMENT; PROBE; IONS
categoria
Chemistry
autores
Barbosa, CDES; da Luz, LL; Paz, FAA; Malta, OL; Rodrigues, MO; Junior, SA; Ferreira, RAS; Carlos, LD
nossos autores
Filipe Alexandre Almeida Paz
Investigador Principal
Luís Carlos
Professor Catedrático
Maria Rute de Amorim e Sá Ferreira André
Professor Catedráticoagradecimentos
The authors gratefully acknowledge CNPq (RH-INCT/INAMI), DPP-UNB, FAP-DF, and CAPES for financial support. This work was partially developed in the scope of the project CICECO - Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2013), financed by Portuguese funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement. LDC acknowledges CAPES and CNPq (Brazil) for a Pesquisador Visitante Especial grant (313778/2013-2) within the Science without Borders program.