Bis-tridentate Chelates of an Asymmetric Ligand: X-ray Structures and Solution NMR Characterization of Divalent Zinc Triad Metal Ion Complexes of N-(2-pyridylmethyl)-N-(2-(methylthio)ethyl)amine.
Bis-tridentate Chelates of an Asymmetric Ligand: X-ray Structures and Solution NMR Characterization of Divalent Zinc Triad Metal Ion Complexes of N-(2-pyridylmethyl)-N-(2-(methylthio)ethyl)amine.
复制标题
不对称配体的双三齿螯合物：N-(2-吡啶基甲基)-N-(2-(甲硫基)乙基)胺二价锌三联体金属离子配合物的X射线结构和溶液NMR表征。
DOI：
10.1016/j.poly.2008.01.018
复制
发表时间：
2008
期刊：
影响因子：
2.6
通讯作者：
Butcher,RaymondJ
中科院分区：
文献类型：
--
作者：
Bebout,DeborahC;Lai,Wei;Stamps,SarahM;Berry,StevenM;Butcher,RaymondJ
分离并表征了M(L)2(ClO4)2(L=N-(2-pyridylmethyl)-N-(2-(methylthio)ethyl)amine)与N4S2金属配位球形成的二价锌三元金属离子络合物。虽然双三齿络合物有九个几何异构体，但三种金属离子的结晶学表征都具有顺式八面体配位几何构型。尽管d10金属离子的配位数和几何构型较低，促进了分子间和分子内的交换过程，但这些双三齿螯合物的稀溶液表现出缓慢的几何异构化。对称性、立体和屏蔽参数支持在低温下观察到的主要和次要化学位移环境的特定异构体指定。在高温下，三种配合物都发生了快速的分子内交换，但通过对Hg(L)22+的JHgH相互作用的检测，发现在耦合恒定时间尺度上分子间交换是缓慢的。这些不同寻常的观察结果在相关双三齿配合物的锌三元金属离子配位化学的背景下进行了讨论。
Divalent zinc triad metal ion complexes of type M(L)2(ClO4)2(L=N-(2-pyridylmethyl)-N-(2-(methylthio)ethyl)amine) with N4S2metal coordination spheres were isolated and characterized by X-ray crystallography and variable temperature proton NMR. Although bis-tridentate chelates have nine geometric isomers, the crystallographically characterized complexes of all three metal ions had trans facial octahedral coordination geometry with Cisymmetry. Despite the low coordination number and geometric preferences of d10metal ions, which facilitate inter- and intramolecular exchange processes, dilute solutions of these bis-tridentate chelates exhibited slow geometric isomerization. Symmetry, sterics and shielding arguments supported specific isomeric assignments for the major and minor chemical shift environments observed at low temperature. At elevated temperature, rapid intramolecular exchange occurred for all three complexes but slow intermolecular exchange on the coupling constant time scale was evidenced through detection of JHgHinteractions for Hg(L)22+. These unusual observations are discussed in the context of the zinc triad metal ion coordination chemistry of related bis-tridentate chelates.