title: Photoelectron spectroscopy of anilinide and acidity of aniline.
abstract: The photoelectron spectrum of the anilinide ion has been measured. The spectrum exhibits a vibrational progression of the CCC in-plane bending mode of the anilino radical in its electronic ground state. The observed fundamental frequency is 524 ± 10 cm(-1). The electron affinity (EA) of the radical is determined to be 1.607 ± 0.004 eV. The EA value is combined with the N-H bond dissociation energy of aniline in a negative ion thermochemical cycle to derive the deprotonation enthalpy of aniline at 0 K; Δ(acid)H(0)(PhHN-H) = 1535.4 ± 0.7 kJ mol(-1). Temperature corrections are made to obtain the corresponding value at 298 K and the gas-phase acidity; Δ(acid)H(298)(PhHN-H) = 1540.8 ± 1.0 kJ mol(-1) and Δ(acid)G(298)(PhHN-H) = 1509.2 ± 1.5 kJ mol(-1), respectively. The compatibility of this value in the acidity scale that is currently available is examined by utilizing the acidity of acetaldehyde as a reference.
authors.affiliation: JILA, University of Colorado and National Institute of Standards and Technology , Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, USA.
authors.forename: Scott W
authors.initials: SW
authors.lastname: Wren
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Vogelhuber
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Ichino
authors.forename: John F
authors.initials: JF
authors.lastname: Stanton
authors.forename: W Carl
authors.initials: WC
authors.lastname: Lineberger