Tweezers-Type Anion Receptors Based on Diphenoxymethane and Biphenol Bearing Urea Groups

Diphenoxymethane (1a and 1b) and biphenol derivatives (1c and 1d) bearing urea groups were prepared to be used in anion recognition. Diphenoxymethane derivative (1a) selectively bound chloride anion (Cl-) in 1:1 complexes. However, biphenol derivatives (1c and 1d) did not show a clear selectivity in anion recognition. The association constants of the complexes were determined by 1H-NMR titrations in CDCl3.