Eu3+ coordination in an organic/inorganic hybrid matrix with methyl end-capped short polyether chains
authors Bermudez, VD; Ostrovskii, D; Goncalves, AC; Lavoryk, S; Carlos, LD; Ferreira, RAS
nationality International
journal JOURNAL OF PHYSICAL CHEMISTRY B
keywords WHITE-LIGHT EMISSION; FULL-COLOR PHOSPHORS; POLYMER ELECTROLYTES; INTENSITY CHANGES; ENERGY-TRANSFER; NANOHYBRIDS; IONS; SPECTROSCOPY; TEMPERATURE; MECHANISMS
abstract Fourier Transform mid-infrared (FT-IR), Fourier Transform Raman (FT-Raman) and photoluminescence spectroscopies and Two-Dimensional (2D) Correlation Spectroscopic Analysis were employed to examine the anionic and cationic local environments in mono-urethanesils doped with europium triflate (Eu(CF3SO3)(3)). The hybrid host framework of these materials is composed of a siliceous backbone bonded through urethane linkages to CH3-terminated polymer chains containing about 7 OCH2CH2 units. Samples with infinity >= n (composition) >= 5 (where n = OCH2CH2/Eu3+) were studied. In terms of ionic association, the level of complexity of these xerogels is very high. In all the compounds the triflate ions exist '' free '', weakly coordinated and forming cross-link separated ion pairs. At 20 >= n >= 5, in addition to all these species contact ion pairs occur. In agreement with these conclusions, photoluminescence establishes the presence of three distinct cation local sites (Eu3+/O=C(urethane cross-links), Eu3+/O-C-C(polyether chains) and weakly coordinated Eu3+/CF3SO3- ionic pairs).
publisher AMER CHEMICAL SOC
issn 1520-6106
year published 2005
volume 109
issue 15
beginning page 7110
ending page 7119
digital object identifier (doi) 10.1021/jp045660v
web of science category Chemistry, Physical
subject category Chemistry
unique article identifier WOS:000228419100032
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