Anthracene-based open and macrocyclic receptors in the flurometric detection of urea

Abstract

Anthracene-based open and macrocyclic receptors 1 and 2 have been designed and synthesized for the recognition of urea in less polar CHCl₃ and more polar CH₃CN solvents. Receptor 1 binds urea strongly in CHCl₃ and exhibits a significant increase in the emission of the anthracene. Macrocyclic analogue 2 shows higher binding and good sensibility towards urea due to the macrocyclic effect. In CH₃CN, the binding constant values are lower in magnitude, but the trend is similar to that seen in CHCl₃. Both the receptors 1 and 2 are examples of PET sensors for the recognition of urea.