Vibrational analysis of C-H stretching overtones in pyridine and 2,6-lutidine
Anno: 1991
Autori: Bini R., Foggi P., Della Valle R.G.
Affiliazione autori: LENS (European Laboratory for Non-Linear Spectroscopy), Largo E. Fermi 2, I-50125 Firenze, Italy; Dipartimento di Chimica, Università di Firenze, Via Gino Capponi 9, I-50121 Firenze, Italy; Dipartimento di Chimica Fisica, Università di Venezia, Calle Larga S. Marta, Dorsoduro 2137, 30123 Venezia, Italy
Abstract: Aryl and methyl C-H stretchings of pyridine and 2,6-lutidine in the liquid phase have been studied in the region of the fundamentals and of the overtones up to the fifth. Standard spectrometers were used to investigate IR and near-IR regions. Thermal lensing laser spectroscopy was used in the visible region. ?n = 1, 2 spectra show a complex pattern that becomes simpler on going to higher ?n values. In this case, the interpretation of the spectra can be made by using the local-mode approach. Stretching frequencies are mainly perturbed by the local environment of bonds, and then new details on molecular structures can be obtained. The observation of the double bands in high-overtone spectra of pyridine is due to differences between properties of the C-H bonds in the 2,6- and 3,4,5-positions. The lower frequency structures in 2,6-lutidine are attributed to conformationally nonequivalent C-H bonds of the methyl groups. Nonnegligible interactions between methyl C-H bonds and the nitrogen atom are responsible for a smaller anharmonicity of the in-plane C-H stretching.
Giornale/Rivista: JOURNAL OF PHYSICAL CHEMISTRY
Volume: 95 (8) Da Pagina: 3027 A: 3031
Parole chiavi: Local mode picture; Morse oscillator; SpectraDOI: 10.1021/j100161a017Citazioni: 15dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2024-04-28Riferimenti tratti da Isi Web of Knowledge: (solo abbonati) Link per visualizzare la scheda su IsiWeb: Clicca quiLink per visualizzare la citazioni su IsiWeb: Clicca qui