Aromatic pi-pi interaction mediated by a metal atom: structure and ionization of the bis(eta(6)-benzene)chromium-benzene cluster

Phys Chem Chem Phys. 2010 Jul 21;12(27):7648-53. doi: 10.1039/b923929d. Epub 2010 Jun 4.


Aromatic pi-pi interaction in the presence of a metal atom has been investigated experimentally and theoretically with the model system of bis(eta(6)-benzene)chromium-benzene cluster (Cr(Bz)(2)-Bz) in which a free solvating benzene is non-covalently attached to the benzene moiety of Cr(Bz)(2). One-photon mass-analyzed threshold ionization (MATI) spectroscopy and first principles calculations are employed to identify the structure of Cr(Bz)(2)-Bz which adopts the parallel-displaced configuration. The decrease in ionization potential for Cr(Bz)(2)-Bz compared with Cr(Bz)(2), resulting from the increase of the cation-pi stabilization energy upon ionization, is consistent with the parallel-displaced structure of the cluster. Theoretical calculations give the detailed cluster structures with associated energetics, thus revealing the nature of pi-pi-metal or pi-pi-cation interactions at the molecular level.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Benzene / chemistry*
  • Cations / chemistry
  • Chromium / chemistry*
  • Metals / chemistry*
  • Models, Chemical
  • Organometallic Compounds / chemistry*
  • Solvents / chemistry
  • Spectrum Analysis


  • Cations
  • Metals
  • Organometallic Compounds
  • Solvents
  • Chromium
  • Benzene