Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.13/33477

OpenURL Link
Title
Excited state acidity of bifunctional compounds. Part 8. Competitive kinetics between solvent reorientation and proton transfer during ESIPT of 2-hydroxyphenyl-lapazole in protic solvents
Author/Creator
Carvalho, Carlos E. M.;  Silva, Alexsander S.;  Brinn, Ira M.;  Pinto, Antonio V.;  Pinto, Maria C. F. R.;  Lin, Su;  Moore, Thomas A.;  Gust, Devens;  Maeder, Marcel
Institution
The University of Newcastle. Faculty of Science & Information Technology, School of Environmental and Life Science
Description
2-Hydroxyphenyl-lapazole (HPL) is shown to undergo excited state intramolecular proton transfer (ESIPT) in the protic solvents methanol, propan-2-ol and octan-1-ol at room temperature. Investigation of the kinetics of this process, using time-resolved single photon counting and transient absorption spectroscopy, indicates the presence of three different excited-state species. These results are very different from that already reported for HPL in non-protic solvents, where it was found that the ESIPT process attains equilibrium during the lifetime of the excited state. Factor analysis of the steady state spectra supports the conclusions drawn from the kinetic results. The difference in behavior as a function of solvent is attributed to two factors that depend on the stronger solute–solvent interactions in the case of the protic solvents. (1) The slight slowing down of the process of proton transfer, which prevents equilibrium from being established during the lifetime of the excited singlet state. (2) The weakening of the intramolecular hydrogen bond, which allows rotation of the hydroxyphenyl moiety.
Relation
Physical Chemistry Chemical Physics Vol. 4, Issue 14, p. 3383-3389
Publisher Link
http://dx.doi.org/10.1039/b202326a
Date
2002
Publisher
Royal Society of Chemistry
Keyword(s)
2-hydroxyphenyl-lapazole;  excited state intramolecular proton transfer;  protic solvents;  transient absorption spectroscopy;  hydroxyphenyl moiety;  intramolecular hydrogen bond
Resource Type
journal article
Identifier
http://hdl.handle.net/1959.13/33477
Identifier
ISSN:1463-9076
Reviewed
Reviewed
52 Visitors 57 Hits 0 Downloads
Save/E-mail Citation
Citation Format
E-mail Address
Subject
"Physical Chemistry Chemical Physics"
 
OR