Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Metal-organic charge transfer can produce biradical states and is mediated by conical intersections

Oksana Tishchenko, Ruifang Li, Donald G. Truhlar and Nicholas J. Turro
Proceedings of the National Academy of Sciences of the United States of America
Vol. 107, No. 45 (November 9, 2010), pp. 19139-19145
Stable URL: http://www.jstor.org/stable/25748640
Page Count: 7
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Metal-organic charge transfer can produce biradical states and is mediated by conical intersections
Preview not available

Abstract

The present paper illustrates key features of charge transfer between calcium atoms and prototype conjugated hydrocarbons (ethylene, benzene, and coronene) as elucidated by electronic structure calculations. One- and two-electron charge transfer is controlled by two sequential conical intersections. The two lowest electronic states that undergo a conical intersection have closed-shell and open-shell dominant configurations correlating with the 4s² and 4s¹3d¹ states of Ca, respectively. Unlike the neutralionic state crossing in, for example, hydrogen halides or alkali halides, the path from separated reactants to the conical intersection region is uphill and the charge-transferred state is a biradical. The lowest-energy adiabatic singlet state shows at least two minima along a single approach path of Ca to the π system: (i) a van der Waals complex with a doubly occupied highest molecular orbital, denoted ϕ²₁, and a small negative charge on Ca and (ii) an open-shell singlet (biradical) at intermediate approach (Ca/C distance ≈2.5–2.7 Å) with molecular orbital structure ϕ₁ϕ₂, where ϕ₂ is an orbital showing significant charge transfer form Ca to the π-system, leading to a one-electron multicentered bond. A third minimum (iii) at shorter distances along the same path corresponding to a closed-shell state with molecular orbital structure ϕ²₂ has also been found; however, it does not necessarily represent the ground state at a given Ca/C distance in all three systems. The topography of the lowest adiabatic singlet potential energy surface is due to the one- and two-electron bonding patterns in Ca-π complexes.

Page Thumbnails

  • Thumbnail: Page 
[19139]
    [19139]
  • Thumbnail: Page 
19140
    19140
  • Thumbnail: Page 
19141
    19141
  • Thumbnail: Page 
19142
    19142
  • Thumbnail: Page 
19143
    19143
  • Thumbnail: Page 
19144
    19144
  • Thumbnail: Page 
19145
    19145