title: Solvent-dependent fluorescence lifetimes of estrone, 17β-estradiol and 17α-ethinylestradiol.
abstract: The fluorescence lifetimes of the estrogens, estrone, 17β-estradiol and 17α-ethinylestradiol, were studied in various solvents. The fluorescence lifetimes of 17β-estradiol and 17α-ethinylestradiol decreased from 4.7 to 0.9 ns as the solvent hydrogen bond accepting ability increased, in good agreement with other phenolic molecules. Estrone's two fluorescence bands had distinct lifetimes, with the 304 nm band having a lifetime shorter than 200 ps, reflecting efficient energy transfer to the carbonyl group, which had lifetimes ranging from 4.4 to 4.9 ns depending on the solvent. Solvent effects on the (1) ππ*, (1) πσ* and (1) nπ* states that are relevant to estrogen photophysics can adequately explain these trends. The solvent dependence on the excited states of these potent endocrine disruptors has significant implications for their photochemistry.
authors.affiliation: Department of Chemistry, Northern Kentucky University, Highland Heights, KY, USA.
authors.forename: Kara Y
authors.initials: KY
authors.lastname: Chan
authors.forename: Benoît
authors.initials: B
authors.lastname: Courtois
authors.forename: Krista
authors.initials: K
authors.lastname: Loose
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Hare
mesh_terms: D052244:Endocrine Disruptors / Q000737:chemistry*; D004735:Energy Transfer; D004958:Estradiol / Q000737:chemistry*; D004970:Estrone / Q000737:chemistry*; D004997:Ethinyl Estradiol / Q000737:chemistry*; D005453:Fluorescence; D006860:Hydrogen Bonding; D010782:Photolysis; D012997:Solvents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D052244:Endocrine Disruptors; D012997:Solvents; D004970:Estrone; D004997:Ethinyl Estradiol; D004958:Estradiol