Synthesis and anion-selective complexation of cyclophane-based cyclic thioureas
Cyclic thiourea derivatives having three different types of cyclophane structure, ortho-meta, meta-meta, and meta-para, and a lariat-type thiourea, were synthesized, and their anion-binding ability was examined. The association constants for the complexation between the receptors and several anions in DMSO-d(6) were measured by the titration method using (1)H NMR spectroscopy. All receptors, except for the meta-para cyclophane, exhibit selective binding to the dihydrogenphosphate anion, which is stronger than that of the acyclic reference compound. The lariat-type receptor binds anions even more strongly than the cyclic receptors which do not possess the third binding site.
Sasaki
Si
Department of Chemistry, Faculty of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
Mizuno
M
Naemura
K
Tobe
Y