title: Experimental and theoretical (DFT) characterization of the excited states and N-centered radical species derived from 2-aminobenzimidazole, the core substructure of a family of bioactive compounds.
abstract: Fluorescence spectroscopy, laser flash photolysis (LFP), and density functional theory (DFT) calculations have been performed to understand the photobehavior of 2-aminobenzimidazole (1). The emission lifetime and quantum yield are solvent-dependent. Direct LFP of 1 at 266 nm in MeCN solution results in the generation of a transient identified as radical 1(-H)(*) by comparison with the species generated upon tert-butyl peroxide (ROOR) irradiation in the presence of 1. In addition, a transient assigned as the triplet state is detected in MeOH solution. Theoretical DFT studies on the hydrogen abstraction process support formation of a 1...OR complex, which undergoes nitrogen to oxygen hydrogen transfer, producing the above-mentioned 1(-H)(*) radicals.
authors.affiliation: Departamento de Química/Instituto de Tecnología Química UPV-CSIC, Universidad Politécnica de Valencia, Avenida de los Naranjos s/n, E-46022 Valencia, Spain.
authors.forename: Verónica
authors.initials: V
authors.lastname: Viudes
authors.forename: Pavel
authors.initials: P
authors.lastname: Bartovský
authors.forename: Luis R
authors.initials: LR
authors.lastname: Domingo
authors.forename: Rosa
authors.initials: R
authors.lastname: Tormos
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Miranda
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D001562:Benzimidazoles / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D008968:Molecular Conformation; D010545:Peroxides / Q000737:chemistry*; D010782:Photolysis; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence
chemical_list: D000097:Acetonitriles; D001562:Benzimidazoles; D005609:Free Radicals; D010545:Peroxides; C027391:2-aminobenzimidazole; D000432:Methanol