A new family of bis-ureidic receptors for pyrophosphate optical sensing

A new family of bis-ureidic receptors (L¹1–L⁶6) has been synthesised. The binding properties of L¹1–L⁶6 towards different anions (acetate, benzoate, glutarate, malonate, dihydrogen phosphate, hydrogen pyrophosphate, triphosphate, AMP and ADP) have been studied by means of ¹H-NMR, UV-Vis and fluorescence spectroscopies and a remarkable affinity for HPpi³⁻ has been observed in the case L³3 (in DMSO-d₆ and DMSO-d₆–5% H₂O) which also acts as a fluorimetric chemosensor, even to the naked eye, for this anion. Theoretical calculations helped us explain the binding properties observed.