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Acid-base behavior of 3-aminoquinoline in its ground and excited states

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Field Value
 
Title Acid-base behavior of 3-aminoquinoline in its ground and excited states
 
Creator PANDA, D
GHOSH, D
DATTA, A
 
Subject accurate experimental values
density-functional theory
pk(a) calculations
nafion membranes
proton-transfer
free-energies
solvation
spectra
hydration
exchange
fluorescence
photophysics
pk(b)
nafion
 
Description Electronic absorption and fluorescence spectroscopic techniques reveal that the pK(b) for neutral form (N) of 3-aminoquinoline (3AQ) is 5-5.7, in the ground as well as the first electronically excited state. However, the case is quite different for the second pK(b), involving the monocation and the dication. The emissive state is found to be monocationic, even in highly acidic conditions and in nafion membrane, where the ground state of the molecule is predominantly dicationic. This indicates that the dication loses a proton in its electronically excited state, possibly due to the delocalization of the lone pair on the amino nitrogen atom over the ring, due to an intramolecular charge transfer. The pKb values have been computed using density functional theory (DFT) for the equilibria of neutral reversible arrow monocation and monocation reversible arrow dication respectively and found to be reasonably in good agreement with the experimental observations. (C) 2009
 
Publisher ELSEVIER SCIENCE SA
 
Date 2011-07-27T15:27:36Z
2011-12-26T12:57:33Z
2011-12-27T05:43:22Z
2011-07-27T15:27:36Z
2011-12-26T12:57:33Z
2011-12-27T05:43:22Z
2009
 
Type Article
 
Identifier JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY, 207(2-3), 254-259
1010-6030
http://dx.doi.org/10.1016/j.jphotochem.2009.07.017
http://dspace.library.iitb.ac.in/xmlui/handle/10054/7260
http://hdl.handle.net/10054/7260
 
Language en