In a research paper soon to appear in the Journal of Organic Chemistry (JOC) of the American Chemical Society (DOI: 10.1021/jo500234w), Professor Athula Attygalle from Stevens’ Department of Chemistry, Chemical Biology, and Biomedical Engineering, and his colleagues from Merck Research Laboratories, Rahway, New Jersey, describe a novel and fascinating gas-phase ion fragmentation mechanism.
“Acceptance of this paper is excellent recognition for the fundamental, basic research that is being accomplished, research that often goes unacknowledged” says Attygalle. “The reviewing process in JOC is very stringent, and the journal has a wide readership.”
Mass spectrometry is one the most widely deployed techniques for identifying unknown chemicals. In order to record a mass spectrum, gaseous ions are generated from a sample, and fragmented to smaller pieces. By measuring masses and abundances of the fragments ions produced in this way, a spectrum characteristic for each compound is generated. To interpret a mass spectrum, we must understand the rules that govern the fragmentations pathways. The research areas of the Attygalle group include deciphering ion fragmentation tenets that are diagnostically useful for structure elucidation of chemical compounds.
It is generally believed that once a charge is imparted to a benzene ring, the hydrogen atoms attached to the ring scramble and lose their the positional integrity. However, experimental results reported in the JOC article demonstrate that the hydrogen atoms on a benzene ring do not usually undergo scrambling under negative-ion conditions. On the other hand if a methoxy group is present adjacent to the negative charge, then the negative charge circumambulates.
The Journal of Organic Chemistry has a reputation of a very stringent reviewing process; three or more peers usually review submissions. Reviewer comments made before the paper was accepted for publication include: “The manuscript reports on a fascinating observation concerning the mass spectrometric fragmentation of methoxybenzoate ions.” “The authors nicely and systematically investigated the outcome of this fragmentation behavior for related di- and trimethoxy-substituted phenyl anions generated from the respective benzoate ions.” “I am sure that this study will be the basis for textbook examples for the organic chemistry ratio in mass spectrometric fragmentation.” “The experimental design of this paper is perfect and it is an excellent work on physical organic chemistry and gas-phase ion chemistry.”