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 CN (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.

中文翻译：

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铕和铽二新戊酰基甲烷酸酯和其他具有 2,2'-联吡啶的 β-二酮酸酯的结构、发光和拉曼光谱

该研究揭示了具有 2,2'-联吡啶衍生物 [Ln(DPM)3L] (Ln = Eu, Tb; L = 2,2'-联吡啶, 4,4'-二甲基-2,2'-联吡啶、4,4'-二苯基-2,2'-联吡啶）和氟化 β-二酮酸酯 [Ln(β)3Bpy]（β = TTFA、TFAA、BTFA），其中 CN (Ln3+) = 8 和方形反棱镜形式的 LnN2O6 配位多面体。我们讨论了由于取代基的供体 - 受体性质和空间因子的变化而导致 β-二酮酸盐中 Eu-O 和 Eu-N 键长差异导致的结构规律。考虑了 Eu 配位多面体的主要畸变 Δ = r(Eu-N) – r(Eu-O) 对发光光谱和振动拉曼光谱的影响。5D0–7F2 (Eu3+) 电偶极跃迁的相对强度（表征 Eu3+ 离子最近环境的畸变程度）与激发电子态 5D0 (Eu3+) 和 5D4 ( Tb3+）。讨论了配体高频振动引起的非辐射过程对 5D0 (Eu3+) 和 5D4 (Tb3+) 能级衰减率的贡献。从研究 Bpy 分子的振动频率的变化取决于 Eu 配位多面体的畸变 Δ 来分析拉曼光谱。讨论了配体高频振动引起的非辐射过程对 5D0 (Eu3+) 和 5D4 (Tb3+) 能级衰减率的贡献。从研究 Bpy 分子的振动频率的变化取决于 Eu 配位多面体的畸变 Δ 来分析拉曼光谱。讨论了配体高频振动引起的非辐射过程对 5D0 (Eu3+) 和 5D4 (Tb3+) 能级衰减率的贡献。从研究 Bpy 分子的振动频率的变化取决于 Eu 配位多面体的畸变 Δ 来分析拉曼光谱。