Strong anion receptors based on antiaromaticity/aromaticity switching

Abstract

A new class of anion receptors was designed using N-boryl and N-beryllium pyrrole derivative and their anion affinities were assessed in gas phase. The mechanism of these anion receptors is basis on aromatization of the pyrrole ring upon interaction with an anion. The anion affinities of these compounds toward F−, Cl−, NO3−, and SO42− anions, computed at the B3LYP/6-311++G(d,p) level of theory, were in the range of 100–808 kJ·mol−1 indicating that these compounds are among the strongest anion receptors reported so far. Also, the anion receptors exhibit exceptional affinity toward SO42− so that they can be considered as selective SO42− receptors.