Andrez Julie, Bozoklu Gülay, Nocton Grégory, Pécaut Jacques, Scopelliti Rosario, Dubois Lionel, Mazzanti Marinella
Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland).
Univ. Grenoble Alpes, INAC-SCIB, F-38000 Grenoble, France, CEA, INAC-SCIB, 38000 Grenoble (France).
Chemistry. 2015 Oct 19;21(43):15188-200. doi: 10.1002/chem.201502204. Epub 2015 Aug 21.
The preparation and characterization of a series of complexes of the Yb and Eu cations in the oxidation state II and III with the tetradentate N,O-donor tripodal ligands (tris(2-pyridylmethyl)amine (TPA), BPA(-) (HBPA=bis(2-pyridylmethyl)(2-hydroxybenzyl)amine), BPPA(-) (HBPPA=bis(2-pyridylmethyl)(3.5-di-tert-butyl-2-hydroxybenzyl)amine), and MPA(2-) (H2 MPA=(2-pyridylmethyl)bis(3.5-di-tert-butyl-2-hydroxybenzyl)amine) is reported. The X-ray crystal structures of the heteroleptic Ln(2+) complexes [Ln(TPA)I2 ] (Ln=Eu, Yb) and [Yb(BPA)I(CH3 CN)]2 , of the Ln(2+) homoleptic [Ln(TPA)2 ]I2 (Ln=Sm, Eu, Yb) and [Eu(BPA)2 ] complexes, and of the Ln(3+) [Eu(BPPA)2 ]OTf and [Yb(MPA)2 K(dme)2 ] (dme=dimethoxyethane) complexes have been determined. Cyclic voltammetry studies carried out on the bis-ligand complexes of Eu(3+) and Yb(3+) show that the metal center reduction occurs at significantly lower potentials for the BPA(-) ligand as compared with the TPA ligand. This suggests that the more electron-rich character of the BPA(-) ligand results in a higher reducing character of the lanthanide complexes of BPA(-) compared with those of TPA. The important differences in the stability and reactivity of the investigated complexes are probably due to the observed difference in redox potential. Preliminary reactivity studies show that whereas the bis-TPA complexes of Eu(2+) and Yb(2+) do not show any reactivity with heteroallenes, the [Eu(BPA)2 ] complex reduces CS2 to afford the first example of a lanthanide trithiocarbonate complex.
报道了一系列氧化态为II和III的镱（Yb）和铕（Eu）阳离子与四齿N,O供体三脚架配体（三（2-吡啶甲基）胺（TPA）、BPA⁻（HBPA = 双（2-吡啶甲基）（2-羟基苄基）胺）、BPPA⁻（HBPPA = 双（2-吡啶甲基）（3,5-二叔丁基-2-羟基苄基）胺）和MPA²⁻（H₂MPA =（2-吡啶甲基）双（3,5-二叔丁基-2-羟基苄基）胺）形成的配合物的制备和表征。已测定了杂配Ln²⁺配合物[Ln(TPA)I₂ ]（Ln = Eu、Yb）和[Yb(BPA)I(CH₃CN)]₂ 、Ln²⁺同配物[Ln(TPA)₂ ]I₂ （Ln = Sm、Eu、Yb）和[Eu(BPA)₂ ]配合物以及Ln³⁺ [Eu(BPPA)₂ ]OTf和[Yb(MPA)₂ K(dme)₂ ]（dme = 二甲氧基乙烷）配合物的X射线晶体结构。对Eu³⁺和Yb³⁺的双配体配合物进行的循环伏安法研究表明，与TPA配体相比，BPA⁻配体的金属中心还原发生在显著更低的电位。这表明BPA⁻配体更富电子的特性导致其镧系配合物比TPA的镧系配合物具有更高的还原特性。所研究配合物在稳定性和反应性方面的重要差异可能归因于观察到的氧化还原电位差异。初步反应性研究表明，虽然Eu²⁺和Yb²⁺的双TPA配合物与杂丙二烯没有任何反应性，但[Eu(BPA)₂ ]配合物将CS₂还原，得到了镧系三硫代碳酸盐配合物的首个实例。
