title: Characterisation of the lowest singlet and triplet excited states of S-flurbiprofen.
abstract: The photophysical properties of S-flurbiprofen [S-2-fluoro-alpha-methyl-4-biphenylacetic acid], a nonsteroidal anti-inflammatory drug, have been examined using steady-state and time-resolved spectroscopic techniques. The energy of its first singlet excited state is 99 kcal mol(-1). The fluorescence quantum yields and lifetimes (at 300 nm) have been determined in acetonitrile, methanol, hexane and PBS; they are in the range 0.15<phi(F)< 0.33 and 0.7<tau(F)<2.0 ns. The intersystem crossing quantum yields are between 0.45 and 0.71; the lambda(max) of the T-T absorption is 360 nm, and the triplets live from 15 to 106 micros. Steady state photolysis in aqueous medium leads to S-2-hydroxy-alpha-methyl-4-biphenylacetic acid via photonucleophilic aromatic substitution, in addition to the photodecarboxylation products observed in organic solvents.
authors.affiliation: Departamento de Quimica-Instituto de Tecnologia Quimica UPV-CSIC, Universidad Politecnica de Valencia, Camino de Vera s/n, Apdo 22012, 46071, Valencia, Spain.
authors.forename: M Consuelo
authors.initials: MC
authors.lastname: Jiménez
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Miranda
authors.forename: Rosa
authors.initials: R
authors.lastname: Tormos
authors.forename: Ignacio
authors.initials: I
authors.lastname: Vayá
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D001577:Benzophenones; D002851:Chromatography, High Pressure Liquid; D005480:Flurbiprofen / Q000737:chemistry*; D007834:Lasers; D009682:Magnetic Resonance Spectroscopy; D010782:Photolysis; D012997:Solvents; D013050:Spectrometry, Fluorescence
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001577:Benzophenones; D012997:Solvents; D005480:Flurbiprofen; C047723:benzophenone