We have designed and synthesized new chromogenic anion receptors 1 and 2, which utilized 4-nitrophenylhydrazone as anion recognition moiety. UV–vis and1H NMR titration showed that receptors 1 and 2 bound anions utilizing two hydrazone N–H hydrogen bond and two C–H hydrogen bond. Despite the weak hydrogen bonding abilities of binding motifs, receptor 1 showed affinities for dihydrogen phosphate and acetate and receptor 2 showed relatively strong affinities for dihydrogen phosphate in polar solvent such as 5% DMSO in CH3CN.
- Anion receptor
- C–H hydrogen bond