Lanthanide Complexes Based on β‑Diketonates and a Tetradentate Chromophore Highly Luminescent as Powders and in Polymers

A new type of octacoordinated ternary
β-diketonates complexes of terbium and europium has been prepared
using the anionic tetradentate terpyridine-carboxylate ligand (L) as a sensitizer of lanthanide luminescence in combination
with two β-diketonates ligands 2-thenoyltrifluoroacetyl-acetonate
(tta–) for Eu3+ and trifluoroacetylacetonate
(tfac–) for Tb3+. The solid state structures
of the two complexes [Tb­(L)­(tfac)2] (1) and [Eu­(L)­(tta)2] (2) have been determined by X-ray crystallography. Photophysical and 1H NMR indicate a high stability of these complexes with respect
to ligand dissociation in solution. The use of the anionic tetradentate
ligand in combination with two β-diketonates ligands leads to
the extension of the absorption window toward the visible region (390
nm) and to high luminescence quantum yield for the europium complex
in the solid state (Φ = 66(6)%). Furthermore, these complexes
have been incorporated in polymer matrixes leading to highly luminescent
flexible layers.

本研究制备了一类新型铽与铕的八配位三元β-二酮配合物（β-diketonates complexes），以阴离子四齿三联吡啶羧酸配体（L）作为镧系发光（lanthanide luminescence）敏化剂，同时搭配两种β-二酮类配体：针对Eu³⁺的2-噻吩甲酰三氟丙酮阴离子（tta⁻）与针对Tb³⁺的三氟乙酰丙酮阴离子（tfac⁻）。通过X射线单晶衍射（X-ray crystallography）解析了配合物1[Tb(L)(tfac)₂]与配合物2[Eu(L)(tta)₂]的固态结构。光物理测试与核磁共振氢谱（¹H NMR）结果表明，该类配合物在溶液中具有优异的抗配体解离稳定性。阴离子四齿配体与两种β-二酮类配体的协同使用，使配合物的吸收窗口拓展至可见光区（390 nm），且固态铕配合物的发光量子产率可达Φ=66(6)%。此外，将该类配合物掺入聚合物基质后，可制备得到高发光柔性薄膜。