Electrolyte-concentration and ion-size dependence of excited-state intramolecular charge-transfer reaction in (alkylamino)benzonitriles: time-resolved fluorescence emission studies.
Time-resolved studies with three intramolecular charge-transfer molecules 4-(1-azetidinyl)benzonitrile (P4C), 4-(1-pyrrolidinyl)benzonitrile (P5C), and 4-(1-piperidinyl)benzonitrile (P6C) in ethyl acetate in presence of LiClO(4) indicate that the average reaction time for LE --> CT conversion increases at low electrolyte concentration and then decreases to become comparable and even lower than that in the pure solvent. Except for Mg(2+), the average reaction time decreases linearly with the ion size in perchlorate solutions of ethyl acetate. The observed electrolyte-concentration dependence of the average reaction time for these molecules agrees well with the predictions from the theory of Zwan and Hynes [Chem. Phys. 1991, 152, 169] in the broad barrier overdamped limit with barrier frequency, omega(b) approximately 2 x 10(12) s(-1).
Pradhan
Tuhin
T
Department of Chemical, Biological & Macromolecular Sciences, and Unit for Nano Science & Technology, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700 098, India.
Biswas
Ranjit
R