title: Density functional theory as a tool for the structure determination of radiation-induced bioradicals.
abstract: The use of density functional methods for the elucidation of the structure of radiation-induced bio-radicals by comparison of computed and experimental EPR properties is discussed. Three case studies, radiation induced radicals of the amino acid alanine, steroid hormones and beta-D-fructose, with increasing degree of uncertainty about the proposed radical structures, are investigated. Next to the analysis of the isotropic and anisotropic components of the hyperfine tensor, also the direction cosines of the principal axes of this tensor were investigated in greater detail in the case of the beta-D-fructose radicals. Since all radicals considered in this contribution are formed in a solid matrix, also the question as to how to incorporate the effect of the molecular environment is addressed. It is concluded that the methodology outlined represents a powerful tool to aid experimentalists in the assignment of the contributions of various radicals contributing to the observed EPR spectra.
authors.affiliation: Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB), Faculteit Wetenschappen, Pleinlaan 2, 1050 Brussels, Belgium. fdeprof@vun.ac.be
authors.forename: F
authors.initials: F
authors.lastname: De Proft
authors.forename: E
authors.initials: E
authors.lastname: Pauwels
authors.forename: P
authors.initials: P
authors.lastname: Lahorte
authors.forename: V
authors.initials: V
authors.lastname: Van Speybroeck
authors.forename: M
authors.initials: M
authors.lastname: Waroquier
authors.forename: P
authors.initials: P
authors.lastname: Geerlings
mesh_terms: D000409:Alanine / Q000737:chemistry / Q000528:radiation effects; D000465:Algorithms; D019295:Computational Biology; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry* / Q000528:radiation effects*; D005632:Fructose / Q000737:chemistry / Q000528:radiation effects; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D013256:Steroids / Q000737:chemistry / Q000528:radiation effects
chemical_list: D005609:Free Radicals; D013256:Steroids; D005632:Fructose; D000409:Alanine