DIALKYLAMINOBENZONITRILES AS FLUORESCENCE POLARITY PROBES FOR AQUEOUS SOLUTIONS OF CYCLODEXTRINS

Abstract

Abstract— The dual fluorescence of 4‐(N, N‐dimethylamino)benzonitrile and 4‐(N, N‐diethylamino)‐benzonitrile (DMABN and DEABN, respectively), has been studied in aqueous solutions of cyclodextrins. Fluorescence parameters (peak maximum, lifetime, and relative intensity) have been measured and are found to be consistent with the formation of complexes of probe and cyclodextrin. Enhanced emission of the twisted internal charge transfer state (TICT) fluorescence is observed in cyclodextrin, with the greatest effect for the DMABN/α‐cyclodextrin system. Our results promote further understanding of both the photophysical behavior of DMABN and the complexation of probe with cyclodextrin. The use of dialkylaminobenzonitriles as polarity probes is discussed.