New P-bridgehead urea-based tripodal anion receptors for H 2PO4- recognition

Article abstract of DOI:10.1016/j.tetlet.2012.05.018

A series of new P-bridgehead tripodal urea-based anion receptors 1-3 bearing phosphine oxide (PO) were synthesized and characterized. Their anion-binding ability was examined by UV-vis, ¹H NMR, ³¹P NMR, and ESI-MS. The results revealed that receptors 1-3 showed good sensitivity, selectivity, and binding affinity for H₂PO ₄^- over NO₃^- and Br^-, and among them receptor 2 showed the best binding affinity for H₂PO ₄^- over F^-, Br^-, CH ₃COO^-, HSO₄^-, and NO ₃^-. The Job plot experiments indicated that receptors 1-3 formed 1:1 stoichiometric complex with H₂PO₄^-.