title: X-ray Photoemission Spectra and Electronic Structure of Coumarin and its Derivatives.
abstract: The electronic structures of coumarin and three of its derivatives (7-amino-4-methylcoumarin, 7-amino-4-(trifluoro)methylcoumarin, and 4-hydroxycoumarin) have been studied by theoretical calculations, and compared with experimental valence and core photoelectron spectra to benchmark the predicted spectra. The outer valence band spectra of the first three compounds showed good agreement with theoretical calculations for a single isomer, whereas the spectrum of 4-hydroxycoumarin indicated the presence of more than one tautomer, consistent with published results. Calculations of core level spectra of carbon, nitrogen, oxygen, and fluorine of the first three compounds are also in satisfactory agreement with our measurements. The carbon and oxygen 1s spectra of 4-hydroxycoumarin allow us to identify and quantify the populations of the principle tautomers present. The 4-hydroxy enol form is the most stable isomer at 348 K, followed by the diketo form, with 1.3 kJ·mol(-1) lower energy.
authors.affiliation: Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, Faculty of Sciences, Engineering and Technology, Swinburne University of Technology , Hawthorn, Melbourne, Victoria 3122, Australia.
authors.forename: Anoja P
authors.initials: AP
authors.lastname: Wickrama Arachchilage
authors.affiliation: Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, Faculty of Sciences, Engineering and Technology, Swinburne University of Technology , Hawthorn, Melbourne, Victoria 3122, Australia.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Elettra-Sincrotrone Trieste , Area Science Park, I-34149 Basovizza, Trieste, Italy.
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Feyer
authors.affiliation: Elettra-Sincrotrone Trieste , Area Science Park, I-34149 Basovizza, Trieste, Italy.
authors.forename: Oksana
authors.initials: O
authors.lastname: Plekan
authors.affiliation: Elettra-Sincrotrone Trieste , Area Science Park, I-34149 Basovizza, Trieste, Italy.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Acres
authors.affiliation: Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, Faculty of Sciences, Engineering and Technology, Swinburne University of Technology , Hawthorn, Melbourne, Victoria 3122, Australia.|Elettra-Sincrotrone Trieste , Area Science Park, I-34149 Basovizza, Trieste, Italy.|Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche , Area Science Park, I-34149 Trieste, Italy.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Prince
mesh_terms: D015110:4-Hydroxycoumarins / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D003374:Coumarins / Q000737:chemistry*; D007536:Isomerism; D010100:Oxygen / Q000737:chemistry; D056951:Photoelectron Spectroscopy / Q000379:methods*; D011789:Quantum Theory
chemical_list: D015110:4-Hydroxycoumarins; D003374:Coumarins; D002244:Carbon; C028743:7-amino-4-methylcoumarin; D010100:Oxygen; C068805:4-hydroxycoumarin