Ruiz-Botella Sheila, Vidossich Pietro, Ujaque Gregori, Peris Eduardo
Institute of Advanced Materials (INAM), Universitat Jaume I, Avda. Sos Baynat., 12071-, Castellón, Spain.
Departament de Química, Universitat Autónoma de Barcelona, 08193-, Cerdanyola del Vallès, Catalonia, Spain.
Chemistry. 2016 Oct 24;22(44):15800-15806. doi: 10.1002/chem.201602916. Epub 2016 Sep 22.
Two tetrabenzoimidazolium-resorcinarene cavitands were prepared and used for the recognition of chloride, bromide, iodide, cyanide, nitrate, perchlorate, hexanoate, benzenesulfonate, and p-toluenesulfonate. Binding affinities of the two cavitands were determined by H NMR titration and computational analysis. The observed spectral changes were related to specific interaction sites, which were supported by the computational studies. In the case of the C2-H tetrabenzoimidazolium-resorcinarene, the recognition region of the inorganic anions and hexanoate was located at the rim of the cavitand, although chloride and bromide also interacted with the aromatic C-H bonds located between adjacent arms of the cavitand. By contrast, the recognition of the two anions with an aromatic ring (benzenesulfonate and p-toluenesulfonate) results from encapsulation of the aromatic part of the anions inside the hydrophobic cavity of the host. In the case of the C2-Me tetrabenzoimizazolium-resorcinarene receptor, the ability of the molecule to bind all inorganic anions and hexanoate was suppressed, but the receptor maintained its ability to strongly bind benzenesulfonate and p-toluenesulfonate. This is interpreted in terms of suppression of the ability of the cavitand to form hydrogen bonds at the rim of the molecule due to replacement of the C2-H proton by a methyl group, while the hydrophobic pocket of the molecule maintains its binding abilities.
制备了两种四苯并咪唑啉 - 间苯二酚杯芳烃穴状配体，并用于识别氯离子、溴离子、碘离子、氰离子、硝酸根离子、高氯酸根离子、己酸根离子、苯磺酸根离子和对甲苯磺酸根离子。通过 (^1H) NMR 滴定和计算分析确定了这两种穴状配体的结合亲和力。观察到的光谱变化与特定的相互作用位点有关，这得到了计算研究的支持。对于 C2 - H 四苯并咪唑啉 - 间苯二酚杯芳烃，无机阴离子和己酸根离子的识别区域位于穴状配体的边缘，尽管氯离子和溴离子也与穴状配体相邻臂之间的芳香族 C - H 键相互作用。相比之下，对带有芳环的两种阴离子（苯磺酸根离子和对甲苯磺酸根离子）的识别是由于阴离子的芳香部分被包封在主体的疏水腔内。在 C2 - Me 四苯并咪唑啉 - 间苯二酚杯芳烃受体的情况下，该分子结合所有无机阴离子和己酸根离子的能力受到抑制，但该受体仍保持其强烈结合苯磺酸根离子和对甲苯磺酸根离子的能力。这可以解释为由于甲基取代了 C2 - H 质子，抑制了穴状配体在分子边缘形成氢键的能力，而分子的疏水口袋保持了其结合能力。
