Coordination and supramolecular chemistry of multinucleating ligands containing two or more pyrazolyl-pyridine ‘arms’
Coordination and supramolecular chemistry of multinucleating ligands containing two or more pyrazolyl-pyridine ‘arms’
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DOI：
10.1016/s0010-8545(01)00301-0
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发表时间：
2001-11
影响因子：
20.6
通讯作者：
M. Ward;J. McCleverty;J. Jeffery
中科院分区：
文献类型：
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作者：
M. Ward;J. McCleverty;J. Jeffery
已经制备了多种新配体，其中基于吡唑基-吡啶（二齿）或吡唑基-联吡啶（三齿）片段的两个或三个二齿或三齿螯合单元已连接到中心间隔基上。这可以是硼氢化物单元以得到双-或三(吡唑基)硼酸酯衍生物，或者是芳族(苯基或联苯基)单元。这些配体的一般特征是，它们可以将所有结合“臂”协调到单个金属离子，产生单核复合物，或者它们可以将每个单独的“臂”协调到不同的金属离子，以产生有时非常意外的结构复杂性的多核物质的组装。我们观察到螺旋、螺旋环和四面体笼的自组装，在某些情况下，非配位阴离子在组装过程中发挥着至关重要的模板作用。特别是用 M4(μ3-L)4 和 M4(μ2-L)6 化学计量制备的四面体笼，提供了如何从简单组件组装高对称结构的优雅示例。
A wide variety of new ligands has been prepared in which two or three bidentate or terdentate chelating units, based on pyrazolyl-pyridine (bidentate) or pyrazolyl-bipyridine (terdentate) fragments, have been attached to a central spacer. This may be a borohydride unit to give bis- or tris(pyrazolyl)borate derivatives, or an aromatic (phenyl or biphenyl) unit. A general characteristic of these ligands is that they can coordinate all of their binding ‘arms’ to a single metal ion, giving mononuclear complexes, or they can coordinate each separate ‘arm’ to a different metal ion to give assembly of polynuclear species of occasionally quite unexpected structural complexity. We have observed self-assembly of helicates, helical rings, and tetrahedral cages, in some cases with non-coordinated anions playing a crucial templating role in the assembly process. The tetrahedral cages in particular, which have been prepared with both M4(μ3-L)4and M4(μ2-L)6stoichiometries, provide elegant examples of how high-symmetry structures can assemble from simple components.