Studies on the anion recognition of N-Aryl-N'-(4-Ethyloxybenzoyl) thioureas derivatives by Spectroscopy

The interactions of N-aryl-N'-(4-ethyloxybenzoyl) thioureas derivatives and anions such as F-, Cl-, Br-, I-, CH3COO-, H2PO4-, HSO4- and NO3- in DMSO were investigated by UV-Vis and H-1 NMR spectroscopy. The results showed that hydrogen-bonding complexes were formed between receptors and the three anions such as F-, CH3COO- and H2PO4, and the solutions turned light yellow from colorlessness, but there had no evident binding with Cl-, Br-, I-, HSO4- and NO3-. It was regular that the two receptors had different binding ability with F-, CH3COO- and H2PO4-. For the same anion, the association constants followed the trend: receptor 1a> receptor 1b. The UV-Vis data indicated that a 1 : 1 stoichiometry complex was formed.