Infrared spectroscopy of the pentacoordinated carbonium ion C2H7+

Abstract

The infrared spectrum of C2H7+ has been obtained from 2500 to 4200 cm™1. The apparatus consists of a tandem mass spectrometer with a radio-frequency octopole ion trap. After initial mass selection of the C2H7+ in a sector magnet, the C2H7+ is spectroscopically probed by using a two-color laser scheme while being trapped under ultrahigh-vacuum conditions.The first laser is scanned from 2500 to 4200 cm™1 and excites a C-H stretching vibration. The second laser is a continuous-wave C02 laser and is used to dissociate the vibrationally excited parent ions through a multiphoton process. The fragment ion Hariharan et al.4-5.7

Infrared studies of ionic clusters: The influence of Yuan T. Lee

“…While H 3 + ͑H 2 ͒ 2,3 had the core ion, H 3 + , as the nucleating center for the hydrogen molecules, ten stable points, some with low barriers, were identified on the potential energy surface of H 3 + ·H 2 . 82 The infrared study of the carbonium ion, C 2 H 7 + , 83 served as an interesting model for bonding in hydrocarbon ions, where the issue of "nonclassical" or two-electron threecentered bonds could be addressed. 79 This first experimental study 7,8 established many of the fundamental aspects that are now routinely applied to virtually all infrared ionic cluster studies.…”

Infrared spectroscopy of the acetyl cation and its protonated ketene isomer

“…25 Early experiments included protonated ethane (C 2 H 7 + ) and methane (CH 5 + ). 26,27 In more recent work, Dopfer and co-workers, as well as our own group, have employed new optical parametric oscillator lasers to study carbocation species such as CH 3 + , C 2 H 3 + , C 2 H 5 + , C 3 H 3 + , and C 6 H 7 + (protonated benzene). [28][29][30][31][32][33][34][35][36][37][38][39] Other studies have examined small organic ions containing oxygen, such as HCO + , protonated methanol, protonated ethanol, and protonated formaldehyde.…”

IR Spectrum of the Ethyl Cation: Evidence for the Nonclassical Structure

“…Early mass spectrometric reactivity experiments on isotopically labeled C 2 H 5 + showed evidence for rapid and statistical proton/deuteron scrambling, and thus confirmed the low predicted isomerization barriers. [6] The interpretation of photoionization and photoelectron spectra [4f, 7, 8] 5 + , [9] C 2 H 3 + , [10] C 2 H 7 + ), [11] IR spectra of C 2 H 5 + have not been reported. [12] Although never directly observed as a stable species in solution, [13] C 2 H 5 + has been invoked as reactive intermediate in rearrangements of alkyl cations.…”