Excited state intramolecular charge transfer reaction in nonaqueous electrolyte solutions: Temperature dependence
- Department of Chemical, Biological and Macromolecular Sciences and Unit for Nanoscience and Technology, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700 098 (India)
Temperature dependence of the excited state intramolecular charge transfer reaction of 4-(1-azetidinyl)benzonitrile (P4C) in ethyl acetate (EA), acetonitrile (ACN), and ethanol at several concentrations of lithium perchlorate (LiClO{sub 4}) has been investigated by using the steady state and time resolved fluorescence spectroscopic techniques. The temperature range considered is 267-343 K. The temperature dependent spectral peak shifts and reaction driving force (-{Delta}G{sub r}) in electrolyte solutions of these solvents can be explained qualitatively in terms of interaction between the reactant molecule and ion-atmosphere. Time resolved studies indicate that the decay kinetics of P4C is biexponential, regardless of solvents, LiClO{sub 4} concentrations, and temperatures considered. Except at higher electrolyte concentrations in EA, reaction rates in solutions follow the Arrhenius-type temperature dependence where the estimated activation energy exhibits substantial electrolyte concentration dependence. The average of the experimentally measured activation energies in these three neat solvents is found to be in very good agreement with the predicted value based on data in room temperature solvents. While the rate constant in EA shows a electrolyte concentration induced parabolic dependence on reaction driving force (-{Delta}G{sub r}), the former in ethanol and ACN increases only linearly with the increase in driving force (-{Delta}G{sub r}). The data presented here also indicate that the step-wise increase in solvent reorganization energy via sequential addition of electrolyte induces the ICT reaction in weakly polar solvents to crossover from the Marcus inverted region to the normal region.
- OSTI ID:
- 21559762
- Journal Information:
- Journal of Chemical Physics, Vol. 131, Issue 5; Other Information: DOI: 10.1063/1.3196239; (c) 2009 American Institute of Physics; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
ACETATES
ACETONITRILE
ACTIVATION ENERGY
CHARGE EXCHANGE
ELECTROLYTES
ETHANOL
FLUORESCENCE
INTERACTIONS
LITHIUM PERCHLORATES
REACTION KINETICS
SOLUTIONS
SOLVENTS
STEADY-STATE CONDITIONS
TEMPERATURE DEPENDENCE
TIME RESOLUTION
TRANSFER REACTIONS
ALCOHOLS
ALKALI METAL COMPOUNDS
CARBOXYLIC ACID SALTS
CHLORINE COMPOUNDS
DIRECT REACTIONS
DISPERSIONS
EMISSION
ENERGY
HALOGEN COMPOUNDS
HOMOGENEOUS MIXTURES
HYDROXY COMPOUNDS
KINETICS
LITHIUM COMPOUNDS
LUMINESCENCE
MIXTURES
NITRILES
NUCLEAR REACTIONS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PERCHLORATES
PHOTON EMISSION
RESOLUTION
TIMING PROPERTIES