Organométalliques: Matériaux et Catalyse, UMR 6226 CNRS-UR1 Institut des Sciences Chimiques de Rennes, Université de Rennes 1, 35042, Rennes Cedex, France.
Inorg Chem. 2013 Feb 4;52(3):1610-20. doi: 10.1021/ic302532f. Epub 2013 Jan 16.
The reaction between the tetrakis(2-pyridyl-N-oxidemethylthio)tetrathiafulvalene ligand (L) and Ln(hfac)(3)·2H(2)O precursors (where hfac(-) = 1,1,1,5,5,5-hexafluoroacetylacetonate anion and Ln = Tb(III) (1), Dy(III) (2), Er(III) (3), and Yb(III) (4) and (4b)) leads to the formation of five tetranuclear complexes of formula Ln(4)(hfac)(12)(L)(2)·xCHCl(3)·yC(6)H(14) (n = 1, x = 2, y = 0 for (1), (2), and (4), n = 1, x = 4 for (3), and n = 2, x = 2.5, y = 1 for (4b)). Their X-ray structures reveal that the surrounding of each Ln(III) center is filled by two N-oxide groups coming from two different ligands L. These tetranuclear complexes have the highest nuclearity which is reported until now for coordination compounds of lanthanide involving TTF-based ligands. Direct current (dc) measurements highlight the paramagnetic behavior of the compounds with a significant crystal field effect. The temperature dependences of static magnetic measurements for 4 have been fitted. The ground state corresponds to M(J) = ±5/2 while the first excited state (M(J) = ±3/2) was localized at +214 cm(-1) which was well correlated with the luminescence transition. UV-visible absorption properties have been experimentally measured and rationalized by time-dependent density functional theory (TD-DFT) calculations. Upon irradiation at 77 K and room temperature, in the range 24390-20835 cm(-1), both compounds 3 and 4 display a metal-centered luminescence attributed to (4)I(13/2) → (4)I(15/2) (6660 cm(-1)) and (2)F(5/2) → (2)F(7/2) (signal centered around the value of 9966 cm(-1)) transitions, respectively. The observed six transitions could be attributed to the M(J) state splitting due to the existence of two Yb1 and Yb2 ions with slightly different polyhedra in 4.
四(2-吡啶-N-氧化甲基硫代)四噻吩富勒烯配体（L）与Ln(hfac)(3)·2H(2)O 前体（其中 hfac(-)=1,1,1,5,5,5-六氟乙酰丙酮酸根阴离子，Ln=Tb(III)(1)，Dy(III)(2)，Er(III)(3)和 Yb(III)(4)和(4b))之间的反应生成了Ln(4)(hfac)(12)(L)(2)·xCHCl(3)·yC(6)H(14)（n=1，x=2，y=0 用于(1)，(2)和(4)，n=1，x=4 用于(3)，n=2，x=2.5，y=1 用于(4b)）的五个四核配合物。它们的 X 射线结构表明，每个 Ln(III)中心的周围都被两个来自两个不同配体 L 的 N-氧化物基团填充。这些四核配合物具有迄今为止报道的最高核性，涉及 TTF 基配体的镧系元素配位化合物。直流（dc）测量突出了化合物的顺磁性行为，具有显著的晶体场效应。对 4 的静态磁测量的温度依赖性进行了拟合。基态对应于 M(J)=±5/2，而第一激发态（M(J)=±3/2）位于+214 cm(-1)，与发光跃迁很好地相关。实验测量了紫外-可见吸收性质，并通过时间相关密度泛函理论（TD-DFT）计算进行了合理化。在 77 K 和室温下照射时，在 24390-20835 cm(-1)范围内，化合物 3 和 4 都显示出金属中心发光，归因于(4)I(13/2)→(4)I(15/2)（6660 cm(-1))和(2)F(5/2)→(2)F(7/2)（信号集中在 9966 cm(-1)左右）跃迁，分别。观察到的六个跃迁可以归因于由于在 4 中存在两个略有不同的多面体的 Yb1 和 Yb2 离子，M(J)状态分裂。
