Direct Evidence of the Benzylium and Tropylium Cations as the Two Long-Lived Isomers of C7 H7

Pavol Jusko; Aude Simon; Shreyak Banhatti; Sandra Brünken; Christine Joblin

doi:10.1002/cphc.201800744

Direct Evidence of the Benzylium and Tropylium Cations as the Two Long-Lived Isomers of C₇ H₇

Chemphyschem. 2018 Sep 20;19(23):3182-3185. doi: 10.1002/cphc.201800744. Online ahead of print.

Authors

Pavol Jusko¹, Aude Simon², Shreyak Banhatti³, Sandra Brünken⁴, Christine Joblin¹

Affiliations

¹ Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028, Toulouse Cedex 4, France.
² Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, 31062 Toulouse, France.
³ I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937, Köln, Germany.
⁴ Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED, Nijmegen, The Netherlands.

Abstract

Disentangling the isomeric structure of C₇ H₇ ⁺ is a longstanding experimental issue. We report here the full mid-infrared vibrational spectrum of C₇ H₇ ⁺ tagged with Ne obtained with infrared-predissociation spectroscopy at 10 K. Saturation depletion measurements were used to assign the contribution of benzylium and tropylium isomers and demonstrate that no other isomer is involved. Recorded spectral features compare well with density functional theory calculations. This opens perspectives for a better understanding and control of the formation paths leading to either tropylium or benzylium ions.

Keywords: IR spectroscopy; benzylium; cryogenic ion trap; structure elucidation; tropylium.

Abstract

Grants and funding