Escobar L, Díaz-Moscoso A, Ballester P
Institute of Chemical Research of Catalonia (ICIQ) , The Barcelona Institute of Science and Technology (BIST) , Av. Països Catalans, 16 , 43007-Tarragona , Spain . Email:
Universitat Rovira i Virgili , Departament de Química Analítica i Química Orgànica , c/Marcel·li Domingo, 1 , 43007-Tarragona , Spain.
Chem Sci. 2018 Aug 7;9(36):7186-7192. doi: 10.1039/c8sc03034k. eCollection 2018 Sep 28.
We describe the synthesis of a tetrapyridinium phenyl extended calix[4]pyrrole that is soluble in neutral water solution at mM concentrations. We show that, in pure water, the synthesized calix[4]pyrrole receptor selectively binds the -() conformers of secondary -phenyl-amides and tertiary -methyl--phenyl-formamide with binding affinities larger than 10 M. The conformational selectivity is remarkable owing to the energetic preference of amides to adopt the -() conformation in solution. In this respect, we used two binding models for the mathematical analyses of the titration data and calculated apparent and intrinsic binding constants. The combined action of hydrogen bonding and the hydrophobic effect that operates in the binding of the amides in water is responsible for the large affinities displayed by the receptor.
我们描述了一种四吡啶基苯基扩展杯[4]吡咯的合成，该化合物在毫摩尔浓度下可溶于中性水溶液。我们表明，在纯水中，合成的杯[4]吡咯受体选择性结合仲苯基酰胺和叔甲基苯基甲酰胺的-()构象异构体，结合亲和力大于10 M。由于酰胺在溶液中倾向于采用-()构象的能量偏好，这种构象选择性非常显著。在这方面，我们使用了两种结合模型对滴定数据进行数学分析，并计算了表观和内在结合常数。氢键和疏水效应在水中酰胺结合中的共同作用是受体表现出高亲和力的原因。
