Stopped-flow kinetic analysis of the interaction of cyclo[8]pyrrole with anions

Abstract

The on and off rates corresponding to the binding of two test anions (acetate, AcO -, and dihydrogen phosphate, H 2PO 4 -, studied as their tetrabutylammonium salts) to diprotonated cyclo[8]pyrrole have been determined in CH 3CN using stopped-flow analyses carried out at various temperatures. For dihydrogen phosphate, this afforded the activation enthalpies and entropies associated with both off and on processes. The different dynamic behavior seen for these test anions underscores the utility of kinetic analyses as a possible new tool for the advanced characterization of anion receptors. © 2010 American Chemical Society.