Pentameric Circular Iron(II) Double Helicates and a Molecular Pentafoil Knot
Pentameric Circular Iron(II) Double Helicates and a Molecular Pentafoil Knot
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DOI：
10.1021/ja303355v
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发表时间：
2012-06-06
影响因子：
15
通讯作者：
Schultz, David
中科院分区：
文献类型：
--
作者：
Ayme, Jean-Francois;Beves, Jonathon E.;Schultz, David
我们报道了烷基单胺与常见的双(甲酰基吡啶)-联吡啶基团和铁(II)及氯离子的亚胺缩合反应合成了II型五聚环螺旋化合物。用核磁共振谱、质谱法对环状双链螺旋进行了表征，对于2，4-二甲氧基苄胺衍生的环状螺旋五聚体，用X射线单晶进行了表征。详细研究了影响组装过程的因素(反应物的化学计量、浓度、溶剂、性质和阴离子的量)：氯化物在组装过程中的作用似乎不仅限于简单的模板，而且具有不同铁盐的相关三(联吡啶)配体不能与亚胺配体产生更大的圆形螺旋。使用某些手性胺，可以分离出单手的五聚体环螺旋，并通过圆二色谱确定螺旋的立体化学。通过使用特定的二胺，制备了一种闭合的分子五元油结。用核磁共振谱、质谱学和X射线结晶学对五元油结进行了表征，确认了其拓扑结构，并对其形成原因提供了见解。
We report on the synthesis of II pentameric cyclic helicates formed by imine condensation of alkyl monoamines with a common bis(formylpyridine)-bipyridyl-derived building block and iron(II) and chloride ions. The cyclic double-stranded helicates were characterized by NMR spectroscopy, mass spectrometry, and in the case of a 2,4-dimethoxybenzylamine-derived pentameric cyclic helicate, X-ray crystallography. The factors influencing the assembly process (reactant stoichiometry, concentration, solvent, nature and amount of anion) were studied in detail: the role of chloride in the assembly process appears not to be limited to that of a simple template, and larger circular helicates observed with related tris(bipyridine) ligands with different iron salts are not produced with the imine ligands. Using certain chiral amines, pentameric cyclic helices of single handedness could be isolated and the stereochemistry of the helix determined by circular dichroism. By employing a particular diamine, a closed-loop molecular pentafoil knot was prepared. The pentafoil knot was characterized by NMR spectroscopy, mass spectrometry, and X-ray crystallography, confirming the topology and providing insights into the reasons for its formation.