Time Resolved Surface Enhanced Raman Scattering Studies of 3-Hydroxyflavone on a Ag Electrode
| Autor: | Ronald L. Birke, Minfa Wang, Tudor Spataru, and John R. Lombardi |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Aqueous solution
Chemistry 3-Hydroxyflavone Analytical chemistry Laser Tautomer Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention chemistry.chemical_compound symbols.namesake General Energy law symbols Molecule Nitrogen laser Physical and Theoretical Chemistry Ground state Raman scattering |
| Zdroj: | The Journal of Physical Chemistry C. 111:3044-3052 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/jp0650937 |
| Popis: | Reverse proton transfer (RPT) of 3-hydroxyflavone (3-HF) from the tautomer ground state to normal ground state has been studied by time-resolved surface enhanced Raman scattering (TRSERS) in aqueous solution in the presence of oxygen. The tautomer ground state of 3-HF is formed by an exciting 337 nm nitrogen laser pulse and monitored by a 488 nm Ar+ laser with gated photodiode array detection. B3LYP DFT calculations with 3-HF bound to the apex adatom of a Ag20 cluster model show that a tilted orientation of the molecule with respect to the surface site is reasonable and is consistent with the SERS spectral characteristics. The geometry optimized structures also show that a cyclic monohyrate, 3-HF(H2O), species is stable from which biprotonic PT could take place. By studying the changes of some transient band intensities with time, the lifetime of tautomer 3-HF on a Ag electrode is determined to be 1.4 μs. Besides the photoinduced photo-oxygenation product, evidence for an additional endo-peroxide intermed... |
| Databáze: | OpenAIRE |
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