Conformational changes in matrix-isolated 6-methoxyindole: Effects of the thermal and infrared light excitations

Lopes Jesus A. J., Reva I., Araujo-Andrade C., Fausto R.

JOURNAL OF CHEMICAL PHYSICS, vol.144, no.12, 2016 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 144 Issue: 12
  • Publication Date: 2016
  • Doi Number: 10.1063/1.4944528
  • Journal Name: JOURNAL OF CHEMICAL PHYSICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Istanbul Kültür University Affiliated: Yes

Abstract

Conformational changes induced thermally or upon infrared excitation of matrix-isolated 6-methoxyindole were investigated. Narrowband near-infrared excitation of the first overtone of the N-H stretching vibration of each one of the two identified conformers is found to induce a selective large-scale conversion of the pumped conformer into the other one. This easily controllable bidirectional process consists in the intramolecular reorientation of the methoxy group and allowed a full assignment of the infrared spectra of the two conformers. Matrices with different conformational compositions prepared by narrow-band irradiations were subsequently used to investigate the effects of both thermal and broadband infrared excitations on the conformational mixtures. Particular attention is given to the influence of the matrix medium (Ar vs. Xe) and conformational effects of exposition of the sample to the spectrometer light source during the measurements. (C) 2016 AIP Publishing LLC.