Anion sensing by rhenium(I) carbonyls with polarized N–H recognition motifs

This article describes our recent research results on several rhenium(I) carbonyls complexes with polarized N–H recognition motifs as anion receptors. Structurally simple and easily synthesized luminescent anion receptors containing an amide-type anion binding site and a rhenium(I) tricarbonyl pyridine signaling unit have been developed, and they display outstanding sensitivity and selectivity toward a variety of anionic species. Moreover, thioamides and thiourea derivatives of 2,6-pyridinedicarbonyl dichloride, isophthaloyl dichloride and terephthaloyl dichloride have been synthesized. These ligands have been incorporated in dinuclear rhenium(I) diimine tricarbonyl complexes and provide anion recognition properties in these complexes. Furthermore, the related rhenium(I) complex featuring sulfonamide interacting sites that incorporate the highly chromophoric π-conjugated quinoxaline moiety has been prepared, characterized, and its photophysical properties were also studied.