Single Side Strapping: A New Approach to Fine Tuning the Anion Recognition Properties of Calix[4]pyrroles

Autor: Hee Kyung Na, Vincent M. Lynch, Jonathan L. Sessler, Chang-Hee Lee, Dong Hoon Won, Won Seob Cho, Dae Wi Yoon, Sergey V. Shevchuk
Rok vydání: 2003
Předmět:
Zdroj: Journal of the American Chemical Society. 125:7301-7306
ISSN: 1520-5126
0002-7863
DOI: 10.1021/ja029175u
Popis: 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.
Databáze: OpenAIRE
načítá se...