Abstract
An additional ultrafast blue shift in the transient absorption spectra of hydrogen-bonding complexes of a strong photoacid, 8-hydroxypyrene 1,3,6-trisdimethylsulfonamide (HPTA), over the salvation response of the uncomplexed HPTA and also over that of the methoxy derivative of the photoacid (MPTA) in the presence of the hydrogen-bonding base was observed on optical excitation of the photoacid. The additional 55 ± 10 fs solvation response was found to be about 35% and 19% of the total C(t) of HPTA in dichloromethane (DCM) when it was hydrogen-bonded to dimethylsulfoxide (DMSO) and dioxane, respectively, and about 29% of the total C(t) of HPTA in dichloroethane (DCE) when it was hydrogen-bonded to DMSO. We have assigned this additional dynamic spectral shift to a transient change in the hydrogen bond (O-H⋯O) that links HPTA to the complexing base, after the electronic excitation of the photoacid.
Original language | English |
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Pages (from-to) | 1315-1327 |
Number of pages | 13 |
Journal | ChemPhysChem |
Volume | 5 |
Issue number | 9 |
DOIs | |
State | Published - 20 Sep 2004 |
Keywords
- Femtochemistry
- Hydrogen-bonding interactions
- Photoacids
- Pump-probe spectroscopy
- Solvation dynamics
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry