Abstract:
Covalent capsule 1 was designed to include two molecular baskets linked with three mobile pyridines tucked into its inner space. On the basis of both theory (DFT) and experiments (NMR and X-ray crystallography), we found that the pyridine \"doors\" split the chamber (380 Å3 ) of 1 so that two equally sizeable compartments (190 Å3 ) became joined through a conformationally flexible aromatic barrier. The compartments of such unique host could be populated with CCl4 (88 Å3 ; PC=46 %), CBr4 (106 Å3 ; 56 %) or their combination CCl4 /CBr4 (PC=51 %), with thermodynamic stabilities ΔG° tracking the values of packing coefficients (PC). Halogen (C-X⋅⋅⋅π) and hydrogen bonding (C-H⋅⋅⋅X) contacts held the haloalkane guests in the cavities of 1. The consecutive complexations were found to occur in a negative allosteric manner, which we propose to result from the induced-fit mode of complexation. Newly designed 1 opens a way for probing the effects of inner conformational dynamics on noncovalent interactions, reactivity and intramolecular translation in confined spaces of hollow molecules.
摘要:
共价胶囊1被设计成包括两个分子篮,其与塞入其内部空间的三个可移动的吡啶连接。在理论(DFT)和实验(NMR和X射线晶体学)的基础上,我们发现吡啶“门”将1的室(380µ3)分开,因此两个同等大小的室(190µ3)通过构象灵活的芳香屏障连接。这种独特宿主的隔室可以填充CCl4(88µ3;PC=46%),CBr4(106µ3;56%)或其组合CCl4/CBr4(PC=51%),热力学稳定性ΔG°跟踪填充系数(PC)的值。卤素(C-X白介素π)和氢键(C-H白介素X)触点将卤代烷烃客体保持在1的空腔中。发现连续的络合以负变构方式发生,我们建议这是由于络合的诱导拟合模式。新设计的1为探索内部构象动力学对非共价相互作用的影响开辟了一条途径,中空分子有限空间中的反应性和分子内翻译。