Structure, Vibrational Spectra, and Unimolecular Dissociation of Gaseous 1-Fluoro-1-phenethyl Cations

• DOI: 10.1021/jp804706z
• Publication Date: 2008-10-03T13:15:21Z
• Authors: Jos Oomens; Elfi Kraka; Michael K. Nguyen; Thomas Hellman Mo...
• Keywords: Ethane; Hydrocarbons, Fluorinated; Models, Chemical; Molecular Structure; Spectrophotometry, Infrared; Cations; Gases; Vibration; 01 natural sciences; Mass Spectrometry; 0104 chemical sciences

The multiple CF bond character of PhCFMe (+) ions has been examined by means theory, vibrational spectroscopy the gaseous ions, and unimolecular decomposition chemistry. Atoms in Molecules analysis DFT wave functions gives a order n = 1.25 (as compared with 1.38 for Me 2CF (+), relative to 1 fluoromethane 2 diatomic (+)), which is consistent calculations adiabatic stretching frequencies (nu CF). Experimental gas phase IR spectra, recorded resonant multiphoton dissociation (IRMPD) using free-electron laser connected an FTICR mass spectrometer, show good agreement predicted band positions five deuterated isotopomers (+). Metastable ion decompositions analogues same HF/DF loss patterns as those produced IRMPD. evidence supports conclusion that retain structural integrity until they become sufficiently excited dissociate, whereupon undergo intramolecular hydrogen scrambling competitive expulsion. Relative rates transposition are extracted from experimental fragment abundances. predominant pathway inferred operate via five-center transition state, opposed four-center state HF