Substitution effects on the excited-state intramolecular proton transfer of salicylic acid: an infrared spectroscopic study on the OH stretching vibrations of jet-cooled 5-methoxysalicylic acid
✍ Scribed by Eman Abd El-Hakam Abou El-Nasr; Asuka Fujii; Takayuki Ebata; Naohiko Mikami
- Book ID
- 104108329
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 201 KB
- Volume
- 376
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Infrared spectra of jet-cooled 5-methoxysalicylic acid in the 3-lm region were measured for both the electronic ground (S 0 ) and first excited (S 1 ) states. Effects of the methoxy-substitution were investigated in relation to the excitedstate intramolecular proton transfer of salicylic acid. Though the electronic absorption-emission spectra exhibit the mirror-image relation, which has been regarded as evidence for the suppression of excited-state intramolecular proton transfer, the infrared spectra showed an extremely large elongation of the phenolic O-H bond upon photoexcitation. The results represent that the significant enhancement of the intramolecular hydrogen bond does occur in S 1 of 5methoxysalicylic.