Electron photodetachment from negative ions of C2v symmetry. Electron affinities of allyl and cyanomethyl radicals

DNA and proteins are chiral: Their three-dimensional structures cannot be superimposed with their mirror images. Circular dichroism spectroscopy is widely used to characterize chiral compounds, but data interpretation is difficult in the case of mixtures. We recorded the electronic circular dichroism spectra of DNA helices separated in a mass spectrometer. We studied guanine-rich strands having various secondary structures, electrosprayed them as negative ions, irradiated them with an ultraviolet nanosecond optical parametric oscillator laser, and measured the difference in electron photodetachment efficiency between left and right circularly polarized light. The reconstructed circular dichroism ion spectra resembled those of their solution-phase counterparts, thereby allowing us to assign the DNA helical topology. The ability to measure circular dichroism directly on biomolecular ions expands the capabilities of mass spectrometry for structural analysis.

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ChemInform Abstract: ELECTRON PHOTODETACHMENT FROM PHENYLNITRENE, ANILIDE, AND BENZYL ANIONS. ELECTRON AFFINITIES OF THE ANILINO AND BENZYL RADICALS AND PHENYL NITRENE

Chemischer Informationsdienst ◽

10.1002/chin.198508041 ◽

1985 ◽

Vol 16 (8) ◽

Author(s):

P. S. DRZAIC ◽

J. I. BRAUMAN

Keyword(s):

Electron Affinities ◽

Benzyl Radicals ◽

Electron Photodetachment

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Energetics of the charge-stripping process from negative ions. A new method for the estimation of electron affinities

Journal of the Chemical Society Chemical Communications ◽

10.1039/c39790000983 ◽

1979 ◽

pp. 983 ◽

Cited By ~ 4

Author(s):

Ian Howe ◽

John H. Bowie ◽

Jan E. Szulejko ◽

John H. Beynon

Keyword(s):

Negative Ions ◽

New Method ◽

Electron Affinities

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Negative Ionen durch Elektronenstoß aus organischen Nitroverbindungen, Äthylnitrit und Äthylnitrat

Zeitschrift für Naturforschung A ◽

10.1515/zna-1967-0516 ◽

1967 ◽

Vol 22 (5) ◽

pp. 700-704

Author(s):

K. Jäger ◽

A. Henglein

Keyword(s):

Electron Impact ◽

Negative Ions ◽

Molecular Ions ◽

Ion Source ◽

Negative Ion ◽

Electron Affinities ◽

Low Intensity ◽

Ion Molecule Reactions ◽

Fragment Ions ◽

Product Ions

Negative ion formation by electron impact has been studied in nitromethane, nitroethane, nitrobenzene, tetranitromethane, ethylnitrite and ethylnitrate. Appearance potentials, ionization efficiency curves and kinetic energies of negative ions were measured by using a Fox ion source. The electron affinities of C2H5O and of C (NO2)3 are discussed as well as the energetics of processes which yield NO2-. The electron capture in nitrobenzene and tetranitromethane leads to molecular ions [C6H5NO2~ in high, C (NO2)4 in very low intensity] besides many fragment ions. A number of product ions from negative ion-molecule reactions has also been found.

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