Chiral fluorescent receptors based on (R)-1,1′-binaphthylene-2, 2′-bisthiourea: Synthesis and chiral recognition

Two chiral fluorescent receptors 1 and 2 based on (R)-1,1′- binaphthylene-2,2′-bisthiourea were synthesized, and their chiral recognition properties for enantiomeric mandelate anions were studied by fluorescence spectra and molecular modeling. Addition of the L- and D-mandelate anions caused considerable fluorescent increases in the fluorescent intensity of the host solution. The L-enantiomer can enhance the fluorescence intensity of 1 much more than the D-enantiomer can do, and 1 shows a better enantioselective recognition ability than 2.