Tunability of anion binding strength based on acyl-thiourea receptors containing isatin group.
Some acyl-thiourea derivatives containing isatin group were synthesized and their interactions with anions were investigated using UV-vis spectroscopy and (1)H NMR titrations in DMSO and DMSO-d(6), respectively. These compounds have a same molecular framework, functionalising with different groups lead to different anion binding strength of these receptors. Receptor 1 showed a higher binding affinity for AcO(-) than for F(-), due to the cooperative multiple hydrogen bond interactions of AcO(-) with the acyl-thiourea group and N-H group in the indole unit of receptor 1. Displacing the N-H proton in the indole unit with -CH(3) group, receptor 2 showed no obviously discriminative responses for F(-), AcO(-) and H(2)PO(4)(-) due to lack of such additional binding. In the case of receptor 3, which was functionalised with strong electron-withdrawing group, it showed selectively chromogenic response for F(-) based on double deprotonation of the receptor in DMSO, whereas AcO(-) and H(2)PO(4)(-) induced single deprotonation only.
Hu
Shuzhen
S
Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
Guo
Yong
Y
Xu
Jian
J
Shao
Shijun
S
D000838:Anions / Q000737:chemistry*; D001665:Binding Sites; D007510:Isatin / Q000737:chemistry*; D015394:Molecular Structure; D013057:Spectrum Analysis; D013890:Thiourea / Q000737:chemistry*
D000838:Anions; D007510:Isatin; D013890:Thiourea