Thioamide, urea and thiourea bridged rhenium(I) complexes as luminescent anion receptors

Thioamides, urea 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 the anion recognition properties of these complexes have been studied by luminescence, UV–Vis and 1H NMR spectroscopic methods. The complexes act as receptors for anions via hydrogen bonding and electrostatic interactions. The anion sensing properties of the complexes are compared to earlier amide-based dinuclear rhenium(I) tricarbonyl complexes.