Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5403287 | Journal of Luminescence | 2009 | 7 Pages |
Abstract
FT-IR and Raman vibrational spectra and electronic emission spectra have been recorded for enantiomers of europium complexes with DBM: dibenzoylmethanate 1,2, and TTFA: 2-thenoyltrifluoroacetonate 3,4, employing the chiral ligands LSS(+)- and LRR(-)-4,5-pinene bipyridine. Contrary to the previously published X-ray data, where geometrical differences were stated to occur for particular enantiomers, the vibrational (and the emission) spectra of the individual optical isomers of a complex are not distinguishable. Using excitation into the Eu3+5D2 multiplet term, the emission intensity is weak from 5D1, whereas a complex structure is observed for the 5D0â7FJ transitions. Features in the vibronic sidebands exhibit similar derived vibrational energies to those observed in the Raman spectra. Fittings of 25 4f6 crystal-field energy levels of 2 and 4 have been attempted with some approximations concerning the local Eu3+ environments. The 5D0 emission lifetimes are monoexponential and are 0.5 (1,2) and 0.9Â ms (3,4) at room temperature.
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Authors
Guohua Jia, Chang-Kui Duan, Xi-Li Li, Peter A. Tanner,