N-Tosylpyrrolidine Calixpyrrole: Synthesis and Ion Binding Studies
datasetposted on 18.02.2011, 00:00 by Sung Kuk Kim, Dustin E. Gross, Dong-Gyu Cho, Vincent M. Lynch, Jonathan L. Sessler
The synthesis and preliminary solution phase ion binding properties of the N-tosylpyrrolidine calixpyrrole 2 are reported. This β-octaalkyl-substituted calixpyrrole, the first to be prepared via a direct condensation reaction, was obtained by reacting the 3,4-alkyl-functionalized pyrrole 8 with acetone in the presence of an acid catalyst. On the basis of 1H NMR spectroscopic analyses and isothermal titration calorimetry, it was concluded that, compared with the parent, β-unsubstituted calixpyrrole (1), compound 2 possesses significantly enhanced binding ability for halide anions in chloroform. Furthermore, 2 proved capable of solubilizing in chloroform solution the otherwise insoluble salts, CsF and CsCl. These effects are ascribed to the interactions between the four tosyl groups present in 2 and the counter cations of the halide anion salts.