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Title: Electron attachment to indole and related molecules

Gas-phase formation of temporary negative ion states via resonance attachment of low-energy (0–6 eV) electrons into vacant molecular orbitals of indoline (I), indene (II), indole (III), 2-methylen-1,3,3-trimethylindoline (IV), and 2,3,3-trimethyl-indolenine (V) was investigated for the first time by electron transmission spectroscopy (ETS). The description of their empty-level structures was supported by density functional theory and Hartree-Fock calculations, using empirically calibrated linear equations to scale the calculated virtual orbital energies. Dissociative electron attachment spectroscopy (DEAS) was used to measure the fragment anion yields generated through dissociative decay channels of the parent molecular anions of compounds I-V, detected with a mass filter as a function of the incident electron energy in the 0–14 eV energy range. The vertical and adiabatic electron affinities were evaluated at the B3LYP/6-31+G(d) level as the anion/neutral total energy difference. The same theoretical method is also used for evaluation of the thermodynamic energy thresholds for production of the negative fragments observed in the DEA spectra. The loss of a hydrogen atom from the parent molecular anion ([M-H]{sup −}) provides the most intense signal in compounds I-IV. The gas-phase DEAS data can provide support for biochemical reaction mechanisms in vivo involving initial hydrogen abstraction from the nitrogen atom ofmore » the indole moiety, present in a variety of biologically important molecules.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Dipartimento di Chimica “G. Ciamician”, Universitá di Bologna, via Selmi 2, 40126 Bologna (Italy)
  2. (CIRSA), Universitá di Bologna, via S. Alberto 163, 48123 Ravenna (Italy)
  3. ISOF, Istituto per la Sintesi Organica e la Fotoreattività, C.N.R., via Gobetti 101, 40129 Bologna (Italy)
  4. Institute of Molecule and Crystal Physics, Ufa Research Centre, Russian Academy of Sciences, Prospekt Oktyabrya 151, 450075 Ufa (Russian Federation)
Publication Date:
OSTI Identifier:
22251483
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 18; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANIONS; DENSITY FUNCTIONAL METHOD; ELECTRON ATTACHMENT; EVALUATION; HARTREE-FOCK METHOD; HYDROGEN; IN VIVO; INDENE; INDOLES; SPECTRA; SPECTROSCOPY