Expanding reversible chalcogenide binding: supramolecular receptors for the hydroselenide (HSe?) anion

摘要

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 ~(?) .