Open AccessReactivity of aromatic σ,σ-biradicals toward riboses
Author(s) -
Anthony Adeuya,
Linan Yang,
F. Sedinam Amegayibor,
John J. Nash,
Hilkka I. Kenttämaa
Publication year - 2006
Publication title -
journal of the american society for mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 127
eISSN - 1879-1123
pISSN - 1044-0305
DOI - 10.1016/j.jasms.2006.07.015
Subject(s) - chemistry , reactivity (psychology) , fourier transform ion cyclotron resonance , singlet state , photochemistry , hydrogen atom abstraction , substrate (aquarium) , radical , hydrogen atom , deuterium , ion cyclotron resonance , computational chemistry , ion , excited state , organic chemistry , atomic physics , cyclotron , medicine , physics , alternative medicine , oceanography , alkyl , pathology , geology
The gas-phase reactions of sugars with aromatic, carbon-centered sigma,sigma-biradicals with varying polarities [as reflected by their calculated electron affinities (EA)] and extent of spin-spin coupling [as reflected by their calculated singlet-triplet (S-T) gaps] have been studied. The biradicals are positively charged, which allows them to be manipulated and their reactions to be studied in a Fourier-transform ion cyclotron resonance mass spectrometer. Hydrogen atom abstraction from sugars was found to be the dominant reaction for the biradicals with large EA values, while the biradicals with large S-T gaps tend to form addition/elimination products instead. Hence, not all sigma, sigma-biradicals may be able to damage DNA by hydrogen atom abstraction. The overall reaction efficiencies of the biradicals towards a given substrate were found to be directly related to the magnitude of their EA values, and inversely related to their S-T gaps. The EA of a biradical appears to be a very important rate-controlling factor, and it may even counterbalance the reduced radical reactivity characteristic of singlet biradicals that have large S-T gaps.