Mode-selective excited-state proton transfer in 2-(2 '-pyridyl)pyrrole isolated in a supersonic jet

作者：Kijak Michal; Nosenko Yevgeniy; Singh Ajay; Thummel Randolph P; Waluk Jacek^*

来源：Journal of the American Chemical Society, 2007, 129(10): 2738-+.

DOI：10.1021/ja068109f

Excitation of 2-(2'-pyridyl)pyrrole, a molecule with a weak intramolecular hydrogen bond, leads to proton transfer from the pyrrole to the pyridine nitrogen atom. The reaction occurs even for a cold molecule isolated in a molecular beam. The process is highly vibrational-mode-selective. Only those vibrations that strengthen the hydrogen bond are observed in the excitation spectrum of the tautomeric emission. On the contrary, excitation of out-of-plane modes hinders the reaction. Excited-state intramolecular proton transfer (ESIPT) in the jet occurs via tunneling. H/D isotope effects of 30-60 or higher are observed, with the values crucially dependent on the mode of vibrational excitation.

• 出版日期2007-3-14