Anion Receptors Composed of Hydrogen- and Halogen-Bond Donor Groups: Modulating Selectivity With Combinations of Distinct Noncovalent Interacitons
Anion Receptors Composed of Hydrogen- and Halogen-Bond Donor Groups: Modulating Selectivity With Combinations of Distinct Noncovalent Interacitons
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DOI：
10.1021/ja202096f
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发表时间：
2011-07-13
影响因子：
15
通讯作者：
Taylor, Mark S.
中科院分区：
文献类型：
--
作者：
Chudzinski, Michael G.;McClary, Corey A.;Taylor, Mark S.
提出了一系列基于尿素的阴离子受体的研究，旨在探索通过氢键和卤素键的组合识别阴离子的潜力。质子和氟核磁共振光谱表明，这两种相互作用协同作用以实现某些阴离子的结合，这一结论得到了计算研究的支持。用氟（不参与卤素键合）替换提供卤素键的碘取代基可以估计这种相互作用对阴离子结合自由能的贡献。还讨论了由于使用全氟芳烃官能化脲作为对照受体而产生的阴离子和缺电子芳烃之间吸引接触的证据。卤素键自由能贡献的大小取决于连接氢键和卤素键供体基团的基团的几何特征以及结合阴离子的特性。结果根据卤素键相互作用的基本特征进行解释，包括其方向性和对卤化物相对于含氧阴离子的不同寻常的偏好。两种不同的非共价相互作用之间的合作会对受体选择性产生不寻常的影响，这是卤素键和氢键供体基团与阴离子相互作用的根本差异的结果。
Studies of a series of urea-based anion receptors designed to probe the potential for anion recognition through combinations of hydrogen and halogen bonding are presented. Proton- and fluorine-NMR spectroscopy indicates that the two interactions act in concert to achieve binding of certain anions, a conclusion supported by computational studies. Replacement of the halogen-bond donating iodine substituent by fluorine (which does not participate in halogen bonding) enables estimation of the contribution of this interaction to the free energy of anion binding. Evidence for attractive contacts between anions and electron-deficient arenes arising from the use of perfluoroarene-functionalized ureas as control receptors is also discussed. The magnitude of the free energy contribution of halogen bonding depends both on the geometric features of the group linking the hydrogen- and halogen-bond donor groups and on the identity of the bound anion. The results are interpreted in relation to fundamental features of the halogen-bonding interaction, including its directionality and unusual preference for halides over oxoanions. Cooperation between two distinct noncovalent interactions leads to unusual effects on receptor selectivity, a result of fundamental differences in the interactions of halogen- and hydrogen-bond donor groups with anions.