| Autor: |
Ramesdonk HJ; Chemistry Department, HIMS, University of Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands., Bakker BH, Groeneveld MM, Verhoeven JW, Allen BD, Rostron JP, Harriman A |
| Jazyk: |
angličtina |
| Zdroj: |
The journal of physical chemistry. A [J Phys Chem A] 2006 Dec 14; Vol. 110 (49), pp. 13145-50. |
| DOI: |
10.1021/jp0663098 |
| Abstrakt: |
Femtosecond transient absorption spectroscopy was employed to determine quantitatively the ultrafast S1-T1 intersystem crossing in a 2-substituted 9,10-anthraquinone derivative (3), kisc = 2.5 x 10(12) s-1. Notwithstanding this rapid process, photoexcitation of dyad 1 is followed by competition between intersystem crossing and intramolecular charge separation, the latter leading to a short-lived (2 ps) singlet charge-transfer (CT) state. The local triplet state itself undergoes slower charge separation to populate a relatively long-lived (130 ns) triplet CT state. An earlier report about the formation of an extremely long-lived CT state (> 900 micros) in 1 was found to be erroneous and was related to the sacrificial photo-oxidation of the dimethylsulfoxide solvent used in that study. Finally, some important criteria have been formulated for future experimental validation of "unusually long-lived" CT states. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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