de Namor Angela F Danil, Abbas Ismail
Laboratory of Thermochemistry, Chemistry Division, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey, United Kingdom.
J Phys Chem B. 2007 May 31;111(21):5803-10. doi: 10.1021/jp070760x. Epub 2007 May 4.
Two sulfur-containing hybrid calix[4]pyrrole derivatives (III and IV) have been synthesized and fully characterized. Several analytical techniques (1H NMR, conductance measurements, UV-vis spectrophotometry, titration potentiometry, and titration calorimetry) have been used to assess the interaction between these hybrid calixpyrrole receptors and metal cations in acetonitrile and dimethylsulfoxide. The partition constants of calix[4]pyrrole, I, II, and IV in the acetonitrile-hexane solvent system and the solubilities of the ligands in various solvents at 298.15 K were determined. 1H NMR measurements reveal the sites of interaction of calixpyrrole ligands with metal cations in CD3CN. Conductance and UV-vis spectrophotometric measurements were performed to establish the composition of mercury(II) calixpyrrole complexes in acetonitrile at 298.15 K. Titration calorimetry was used to quantitatively assess Hg(II)-calixpyrrole interactions. Thus the thermodynamics of complexation of calixpyrrole ligands with the mercury(II) cation in acetonitrile at 298.15 K are reported. Potentiometric titrations were also used to establish the stepwise stability constants for the complexation of calix[3]thieno[1]pyrrole with the Hg(II) cation in acetonitrile at 298.15 K. The results show that replacement of one or more pyrrole units by thiophene rings in calix[4]pyrrole has tuned significantly the discrimination ability of these ligands between anions and enables the produced hybrid calixpyrroles to bind selectively with Hg(II) in acetonitrile. No interaction was observed between these ligands and other metal cations in acetonitrile.
已合成并全面表征了两种含硫杂化杯[4]吡咯衍生物（III和IV）。已使用多种分析技术（1H NMR、电导率测量、紫外可见分光光度法、滴定电位法和滴定量热法）来评估这些杂化杯吡咯受体与乙腈和二甲基亚砜中金属阳离子之间的相互作用。测定了杯[4]吡咯I、II和IV在乙腈 - 己烷溶剂体系中的分配常数以及298.15 K时配体在各种溶剂中的溶解度。1H NMR测量揭示了杯吡咯配体与CD3CN中金属阳离子的相互作用位点。进行了电导率和紫外可见分光光度测量以确定298.15 K时乙腈中汞（II）杯吡咯配合物的组成。滴定量热法用于定量评估Hg（II） - 杯吡咯相互作用。因此报告了298.15 K时乙腈中杯吡咯配体与汞（II）阳离子络合的热力学。电位滴定也用于确定298.15 K时杯[3]噻吩并[1]吡咯与乙腈中Hg（II）阳离子络合的逐步稳定常数。结果表明，杯[4]吡咯中一个或多个吡咯单元被噻吩环取代显著调节了这些配体对阴离子的识别能力，并使生成的杂化杯吡咯能够在乙腈中与Hg（II）选择性结合。在乙腈中未观察到这些配体与其他金属阳离子之间的相互作用。
