- Adriaenssens, L. V.; Estarellas, C.; Vargas Jentzsch, A.; Martínez Belmonte, M.; Matile, S.; Ballester, P. “Quantification of Nitrate-π Interactions and Selective Transport of Nitrate Using Calixpyrroles with Two Aromatic Walls” J. Am. Chem. Soc. 2013, 135, 8324-8330
Herein we disclose the results of our investigations regarding the interactions between the biologically relevant nitrate oxoanion and several “two-wall” aryl-extended calixpyrroles. There exists a clear relationship between the electronic nature of the aromatic walls of the calixpyrroles and the stability of the nitrate⊂calixpyrrole complex. This suggests that NO3−-π interactions have an important electrostatic component. We provide energetic estimates for the interaction of nitrate with several phenyl derivatives. Additionally, we report solid-state evidence for a preferred binding geometry of the nitrate anion included in the calixpyrroles. Finally, the “two-wall” aryl-extended calixpyrroles show excellent activity in ion transport through lipid-based lamellar membranes. Notably the best anion transporters are highly selective for transport of nitrate over other anions.