Abstract
Synthetic supramolecular receptors have been widely used to study reversible solution binding of anions; however, few systems target highly-reactive species. In particular, the hydrochalcogenide anions hydrosulfide (HS(-)) and hydroselenide (HSe(-)) have been largely overlooked despite their critical roles in biological systems. Herein we present the first example of reversible HSe(-) binding in two distinct synthetic supramolecular receptors, using hydrogen bonds from N-H and aromatic C-H moieties. The arylethynyl bisurea scaffold 1 (t) (Bu) achieved a binding affinity of 460 ± 50 M(-1) for HSe(-) in 10% DMSO-d (6)/CD(3)CN, whereas the tripodal-based receptor 2(CF(3)) achieved a binding affinity of 290 ± 50 M(-1) in CD(3)CN. Association constants were also measured for HS(-), Cl(-), and Br(-), and both receptors favored binding of smaller, more basic anions. These studies contribute to a better understanding of chalcogenide hydrogen bonding and provide insights into further development of probes for the reversible binding, and potential quantification, of HSe(-) and HS(-).