Tsaryuk V I, Zhuravlev K P, Szostak R, Vologzhanina A V
STRUCTURE, LUMINESCENCE, AND RAMAN SPECTROSCOPY OF EUROPIUM AND TERBIUM DIPIVALOYLMETHANATES AND OTHER β-DIKETONATES WITH 2,2′-BIPYRIDINE.
Journal of Structural Chemistry
, 2020
, 61 (7).
С. 1026-1037.
ISSN 0022-4766
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Аннотация
The study reveals the relationship between structural and spectroscopic characteristics of lanthanide dipivaloylmethanates with 2,2′-bipyridine derivatives [Ln(DPM)3L] (Ln = Eu, Tb; L = 2,2′-bipyridine, 4,4′-dimethyl-2,2′-bipyridine, 4,4′-diphenyl-2,2′-bipyridine) and fluorinated β-diketonates [Ln(β)3Bpy] (β = TTFA, TFAA, BTFA) with the C.N.(Ln3+) = 8 and the LnN2O6 coordination polyhedron in the form of a square antiprism. We discuss structural regularities resulting from the difference between Eu–O and Eu–N bond lengths in β-diketonates due to the changes in donor-acceptor properties of substituents and the steric factor. The effect of the main distortion Δ = r(Eu–N) – r(Eu–O) of the Eu coordination polyhedron on the luminescence spectra and vibrational Raman spectra is considered. A qualitative correlation is demonstrated between the relative intensity of the 5D0–7F2 (Eu3+) electric dipole transition, which characterizes the degree of distortion of the nearest environment of the Eu3+ ion, and the lifetimes of excited electronic states 5D0 (Eu3+) and 5D4 (Tb3+). The contribution of nonradiative processes caused by high-frequency vibrations of ligands to the decay rate of 5D0 (Eu3+) and 5D4 (Tb3+) levels is discussed. The Raman spectra are analyzed in terms of studying the changes in vibrational frequencies of the Bpy molecule depending on the distortion Δ of the Eu coordination polyhedron.
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STRUCTURE, LUMINESCENCE, AND RAMAN SPECTROSCOPY OF EUROPIUM AND TERBIUM DIPIVALOYLMETHANATES AND OTHER β-DIKETONATES WITH 2,2′-BIPYRIDINE. (deposited 25 Окт 2023 11:45)
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