Spectroscopic investigation of hydrogen atom transfer in the McLafferty rearrangement
Date
2008-04-25Author
Kerstetter, Dale R.
Leavitt, Christopher M.
Groenewold, Gary S.
Steill, Jeffrey D.
Oomens, Jos
Van Stipdonk, Michael J.
Metadata
Show full item recordCitation
Kerstetter, Dale R., Leavitt, Christopher M., Groenewold, Gary S. (2008). Spectroscopic investigation of hydrogen atom transfer in the McLafferty rearrangement. In Proceedings: 4th Annual Symposium: Graduate Research and Scholarly Projects. Wichita, KS: Wichita State University, p.11-12
Abstract
In this study, wavelength-selective infrared multiple-photon photodissociation (WS-IRMPD) was used to study the
transfer of an H atom in a gas-phase unimolecular rearrangement reaction. The reaction studied was the McLafferty
rearrangement, which involves transfer of a γ-position hydrogen atom to a carbonyl oxygen atom through a cyclic intermediate,
followed by the elimination of an alkene. The IRMPD experiment allows for the collection of vibrational spectra of discrete gasphase
ions, which can then be compared to those predicted using density functional theory calculations to assign accurate
composition and structure. For the experiment, the tert-butyl ester of a model peptide, nicotinic acid-glycine, was incubated in a
mixture of deuterium oxide and deuterated methanol. This solution was the used to make ions by electrospray ionization. The
McLafferty rearrangement was then induced by collision-induced dissociation. Following rearrangement, the product ion,
consisting of the model peptide with 2 deuterium atoms and 1 H atom in exchangeable sites, was investigated by IRMPD. The
infrared spectrum produced clearly shows that the H atom is transferred to the C-terminal acid group and no migration to amide
positions occurs on the time scale of the experiment.
Description
Paper presented to the 4th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held at the Hughes Metropolitan Complex, Wichita State University, April 25, 2008.
Research completed at the Wichita State University, Department of Chemistry, Fairmount College of Liberal Arts and Sciences
bIdaho National Laboratory, Idaho Falls, ID, USA
cFOM Instituut voor Plasmafysica, Nieuwigein, The Netherlands