Synthesis of a BINOL-Based C 3 Symmetric Schiff Base and Its Fluorescence Response to Zn 2 .

A novel C 3 symmetric 1,1'-bi-2-naphthol-based Schiff base (R,R,R)-6 has been synthesized which shows highly selective fluorescence enhancement with Zn 2+ among 21 metal cations examined. Its sensitivity and selectivity are found to be greater than other related C 2 (1) and C 1 [(R)-9] symmetric compounds in the fluorescent recognition of Zn 2+ . The mechanistic study reveals that the selective fluorescence enhancement of the probe can be attributed to the formation of a unimolecular multidentate 6-coordinated Zn 2+ complex.