Stereoselective Synthesis of Molecular Square and Granny Knots
作者:David A. Leigh、Lucian Pirvu、Fredrik Schaufelberger
DOI:10.1021/jacs.9b01819
日期:2019.4.10
stereoselective synthesis of both molecular granny and square knots through the use of lanthanide-complexed overhand knots of specific handedness as three-crossing “entanglement synthons”. The composite knots are assembled by combining two entanglement synthons (of the same chirality for a granny knot; of opposite handedness for a square knot) in three synthetic steps: first, a CuAAC reaction joins together
我们报告了通过使用特定旋向性的镧系元素络合物上手结作为三交叉“纠缠合成子”的立体选择性合成分子奶奶结和方结。通过在三个合成步骤中组合两个纠缠合成子(对于奶奶结具有相同的手性;对于方结具有相反的手性),复合结是通过三个合成步骤组合而成的:首先,CuAAC 反应将每个上手结的一端连接在一起。闭环烯烃复分解(RCM)然后提供闭环结,锁定拓扑。这允许随后去除稳定合成子的缠结构象所需的镧系元素离子。复合结通过 1 H 和 13 C NMR 光谱和质谱以及通过圆二色性比较结立体异构体的手性来表征。
Pentadentate Ligands for the 1:1 Coordination of Lanthanide(III) Salts
作者:Markus Albrecht、Sebastian Mirtschin、Olga Osetska、Sabrina Dehn、Dieter Enders、Roland Fröhlich、Tanja Pape、Ekkehardt F. Hahn
DOI:10.1002/ejic.200700222
日期:2007.7
Three hydrazone type ligands, namely 2-H, 3, and 4, which were designed to form 1:1 complexes with lanthanoid(III) ions, are presented. Although the tetradentate ligand 2 - leads to an interesting complex [(2)(2-H)YCl 2 ) with yttrium-(III), a more general principle for the coordination of the metal ions by hydrazone-type ligands can be found with ligand 3, where 1:1 complexes are obtained with an
New Bisaqua Picolinate‐Based Gadolinium Complexes as MRI Contrast Agents with Substantial High‐Field Relaxivities
作者:Aline M. Nonat、Christelle Gateau、Pascal H. Fries、Lothar Helm、Marinella Mazzanti
DOI:10.1002/ejic.201101162
日期:2012.4
led to the formation monoaqua ternary complexes. Even under these conditions, the average relaxivity remains higher or similar than most currently used contrastagents. Only hydrogen carbonate interacts strongly with the complexes and coordinates in a bidentate mode by displacing both water molecules to induce a twofold decrease in the relaxivity. Both complexes interact with serum albumin to form a
Strongly luminescent 5d/4f heterometal–organic macrocycles with open metal sites: post-assembly modification and sensing
作者:Qiang-Yu Zhu、Li-Peng Zhou、Qing-Fu Sun
DOI:10.1039/c9dt00710e
日期:——
Strongly luminescent 5d/4f heterometal–organic macrocycles featuring open metal sites have been constructed, along with their post-assembly modification and sensing properties.
我们构建了具有开放金属位点的强发光 5d/4f 杂金属有机大环,以及它们的组装后修饰和传感特性。
Ln2M complexes (M = Ru, Re) derived from a bismacrocyclic ligand containing a 4,4′-dimethyl-2,2′-bipyridyl bridging unit
作者:Loïc J. Charbonnière、Stephen Faulkner、Carlos Platas-Iglesias、Martín Regueiro-Figueroa、Aline Nonat、Teresa Rodríguez-Blas、Andrés de Blas、William S. Perry、Manuel Tropiano
DOI:10.1039/c2dt32660d
日期:——
Homodinuclear lanthanide complexes derived from a ligand featuring two DO3A chelating sites linked by a 4,4â²-dimethyl-2,2â²-bipyridyl spacer were prepared and characterized. The bipyridyl coordination site of 1 was used to introduce Ru(Bpy)2 and Re(CO)3Cl moieties, leading to the formation of heterometallic dâf2 complexes with general formulae [Ln2·1·Ru(Bpy)2]2+ (Ln = Nd, Eu, Tb, Yb and Lu) and [Ln2·1·Re(CO)3Cl] (Ln = Nd, Yb and Lu). The luminescence properties of the complexes were investigated by means of absorption spectroscopy and steady-state and time-resolved luminescence spectroscopy covering the visible and NIR regions. Both Ru and Re chromophores were shown to act as efficient sensitizers of the NIR emission of Yb and Nd in aqueous solutions. We also consider the unsaturated coordination spheres of the Ln cations in the Ln2·1 complexes, which form ternary complexes with bidentate anions without showing particular synergistic effects for polyanionic species.