4,6-BIS(IMIDAZOLIO)PYRIMIDINE AS A NEW ANION RECEPTOR

New aryl-oligomer type anion receptors bearing two imidazolium units linked by 6-membered ring aryl spacers at meta-positions have been synthesized. Complexation behavior of the receptors with halide ions (Cl - , Br - , and I - in DMSO-d 6 was investigated by 1 H NMR titrations and semi-empirical calculations (MOPAC AMI). Along with the imidazolium C-H protons, the ortho C-H proton of the central aryl unit forms additional hydrogen bond interaction with guest anion. The receptor with pyrimidine unit exhibited significantly improved anion binding properties.