Institut Lavoisier de Versailles , UMR 8180 CNRS, UVSQ, Université Paris-Saclay , Versailles , France.
Nikolaev Institute of Inorganic Chemistry , Siberian Branch of the Russian Academy of Sciences , Novosibirsk 630090 , Russia.
Inorg Chem. 2019 Oct 7;58(19):13184-13194. doi: 10.1021/acs.inorgchem.9b02048. Epub 2019 Sep 25.
In aqueous solution, cyclodextrins (CDs) are able to bind strongly either hydrophobic species or also hydrophilic molecules such as octahedral hexametallic cluster. Systematic investigation of the reactivity between native CDs (α- or β-CD) and water-soluble rhenium clusters [ReQ(CN)] with Q = S, Se, and Te were performed, leading to six new crystal structures revealing different types of supramolecular arrangements. Encapsulation of [ReQ(CN)] (Q = S, Se, or Te) within two β-CDs is observed regardless of the cluster size. Interestingly, different assembling scenarios are pointed out depending on the host-guest matching featured by no, partial, or deep inclusion complexes that involved either primary or secondary rim of the CD tori. In the specific case of α-CD, only the smaller cluster [ReS(CN)] is able to form inclusion complex with the tori host. Solution investigations, using a set of complementary techniques including isothermal titration calorimetry, multinuclear NMR methods, cyclic voltammetry, and electrospray ionization mass spectrometry, corroborate nicely conclusions of the solid-state studies. It appears clearly that size-matching supported by solvent effects play key roles in the stability of the host-guest complexes. At last, circular dichroism studies underline that the chirality induction from cyclodextrins to the rhenium cluster depends strongly on the strength of host-guest interactions.
在水溶液中，环糊精（CDs）能够强烈地结合疏水性物质或亲水性分子，如八面体六配位金属簇。对天然 CDs（α-或β-CD）与水溶性铼簇[ReQ（CN）]（Q = S、Se 和 Te）之间的反应性进行了系统研究，得到了六个新的晶体结构，揭示了不同类型的超分子排列。[ReQ（CN）]（Q = S、Se 或 Te）被包裹在两个β-CD 内，无论簇的大小如何都可以观察到。有趣的是，根据主客体匹配的特征，指出了不同的组装方案，涉及 CD 环的主或次边缘的无、部分或深包容络合物。在α-CD 的特殊情况下，只有较小的簇[ReS（CN）]能够与环糊精的环形成包容络合物。使用一组互补技术的溶液研究，包括等温滴定量热法、多核 NMR 方法、循环伏安法和电喷雾电离质谱法，很好地证实了固态研究的结论。显然，尺寸匹配和溶剂效应支持在主客体络合物的稳定性中起着关键作用。最后，圆二色性研究强调了环糊精对铼簇的手性诱导强烈依赖于主客体相互作用的强度。
