Luminescent EuIII Complexes Immobilized on a Vermiculite Clay Surface. Issue 11 (28th February 2014)

• Record Type: Journal Article
• Authors: Silva, Haryane R. M.; Fonseca, Maria G.; Espínola, José Geraldo P.; Brito, Hermi F.; Faustino, Wagner M.; Teotonio, Ercules E. S.
• Is Part Of: European journal of inorganic chemistry. Issue 11(2014)
• Page Start: 1914
• Page End: 1921
• Publication Date: 2014-02-28
• Subjects: Organic–inorganic hybrid composites -- Clays -- Lanthanides -- Luminescence -- Energy transfer; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201301494
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: Vermiculite clays were leached with nitric acid and functionalized with (3‐chloropropyl)trimethoxysilane. The resulting materials were modified with the methylimidazolium (MID) group to yield cationic surfaces. These materials were characterized by infrared spectroscopy, elemental analyses, and specific surface area. Tetrakis(β‐diketonate)europate(III) complexes, [EuL4 ] – [L = dibenzoylmethane (DBM) and thenoyltrifluoroacetone (TTA)], were immobilized on the vermiculite surface containing the imidazolium cation to yield hybrid surfaces named V x ‐MID‐EuL4 ( x = 0, 1, and 2), in which x represents the acid nitric concentration in mol L –1 that is used in the leaching process. The highest luminescence intensities of the intraconfigurational‐4f 5 D0 → 7 F J transitions (for which J = 0, 1, 2, 3, and 4) arising from [EuL4 ] – complexes were presented by the hybrid materials containing the amount of imidazolium cation, which depend on the leaching process. The excitation and emission spectra suggested an efficient intramolecular energy‐transfer process from ligand‐to‐Eu 3+ ion in the supported materials. The photoluminescent properties of the hybrid materials were investigated based on the emission quantum efficiency ( η ), experimental intensity parameters Ω 2 and Ω 4, and Einstein's emission coefficient ( A 0 J ). The values of these parameters for the V2 ‐MID‐EuL4 surface are close to those assigned to the [EuL4 ] – isolated complexes, which indicates that hybrid vermiculite materials are promising red phosphors. Abstract : Novel hybrid materials based on vermiculite and anionic lanthanide complexes electrostatically connected to 3‐methyl‐1‐propylimidazolium have been prepared. The intramolecular ligand‐to‐metal energy transfers and the luminescent properties have been investigated. The values of the emission quantum efficiencies (>65 %) are the highest yet reported for lanthanide‐containing clay materials.