Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
J Am Chem Soc. 2014 Jul 2;136(26):9491-8. doi: 10.1021/ja504748g. Epub 2014 Jun 20.
Different anionic templates act to give rise to four distinct Cd(II)-based architectures: a Cd2L3 helicate, a Cd8L12 distorted cuboid, a Cd10L15 pentagonal prism, and a Cd12L18 hexagonal prism, which respond to both anionic and cationic components. Interconversions between architectures are driven by the addition of anions that bind more strongly within a given product framework. The addition of Fe(II) prompted metal exchange and transformation to a Fe4L6 tetrahedron or a Fe10L15 pentagonal prism, depending on the anionic templates present. The equilibrium between the Cd12L18 prism and the Cd2L3 triple helicate displayed concentration dependence, with higher concentrations favoring the prism. The Cd12L18 structure serves as an intermediate en route to a hexafluoroarsenate-templated Cd10L15 complex, whereby the structural features of the hexagonal prism preorganize the system to form the structurally related pentagonal prism. In addition to the interconversion pathways investigated, we also report the single-crystal X-ray structure of bifluoride encapsulated within a Cd10L15 complex and report solution state data for J-coupling through a CH···F(-) hydrogen bond indicating the strength of these interactions in solution.
不同的阴离子模板作用，产生了四种不同的基于 Cd(II) 的结构：一个 Cd2L3 螺旋，一个 Cd8L12 扭曲的长方体，一个 Cd10L15 五棱柱，和一个 Cd12L18 六棱柱，它们对阴离子和阳离子都有响应。结构之间的转换是由阴离子的加入驱动的，这些阴离子在给定的产物框架内结合得更牢固。添加 Fe(II) 会促使金属交换，并转化为 Fe4L6 四面体或 Fe10L15 五棱柱，具体取决于存在的阴离子模板。Cd12L18 棱柱和 Cd2L3 三重螺旋之间的平衡表现出浓度依赖性，较高的浓度有利于棱柱。Cd12L18 结构是形成六氟砷酸盐模板的 Cd10L15 配合物的中间体，其中六棱柱的结构特征使系统预组织形成结构相关的五棱柱。除了研究的转换途径外，我们还报告了双氟化物包封在 Cd10L15 配合物中的单晶 X 射线结构，并报告了通过 CH···F(-)氢键的 J 耦合的溶液状态数据，表明这些相互作用在溶液中的强度。
