Lee Chang-Hee, Na Hee-Kyung, Yoon Dae-Wi, Won Dong-Hoon, Cho Won-Seob, Lynch Vincent M, Shevchuk Sergey V, Sessler Jonathan L
Department of Chemistry Kangwon National University Chun-Chon, 200-701 Korea.
J Am Chem Soc. 2003 Jun 18;125(24):7301-6. doi: 10.1021/ja029175u.
Three calix[4]pyrroles bearing m-orcinol-derived diether straps of different lengths on one side of the tetrapyrrolic core have been synthesized and characterized. Structural information for an analogous diester bridged strapped system reported previously (Yoon, D. W.; Hwang, H.; Lee, C. H. Angew. Chem., Int. Ed. Engl. 2002, 41, 1757-1759) is also provided as are bromide and chloride anion affinities for all four systems determined by Isothermal Titration Calorimetry (ITC) in acetonitrile. Although both sets of the strapped calix[4]pyrroles displayed enhanced affinities for chloride and bromide anion, differences were seen among the various receptors that support the conclusion that the anion binding ability of calixpyrrole-type systems can be effectively tuned by modifying the length and nature of the bridging straps. In the specific case of the diether systems, the largest chloride affinity was seen with the shortest strap, whereas the largest affinity for bromide anion was recorded in the case of the longest strap. On the basis of these findings, as well as supporting (1)H NMR spectroscopic studies, it is postulated that not only cavity size per se, but also the ability of the aryl portion of the strap to serve as a CH hydrogen bond donor site are important in regulating the observed anion affinities.
已合成并表征了三种在四吡咯核心的一侧带有不同长度的间苯二酚衍生二醚链的杯[4]吡咯。还提供了先前报道的类似二酯桥连链状体系的结构信息（尹，D.W.；黄，H.；李，C.H.《德国应用化学》，国际版，英文，2002年，41卷，1757 - 1759页），以及通过等温滴定量热法（ITC）在乙腈中测定的所有四个体系对溴离子和氯离子的阴离子亲和力。尽管两组链状杯[4]吡咯对氯离子和溴离子都表现出增强的亲和力，但在各种受体之间观察到了差异，这支持了杯吡咯型体系的阴离子结合能力可以通过改变桥连链的长度和性质来有效调节的结论。在二醚体系的具体情况下，最短链的体系对氯离子的亲和力最大，而最长链的体系对溴离子的亲和力最大。基于这些发现以及辅助的¹H NMR光谱研究，推测不仅空腔尺寸本身，而且链的芳基部分作为CH氢键供体位点的能力在调节观察到的阴离子亲和力方面都很重要。
