Journal of Molecular Modeling

, Volume 12, Issue 5, pp 569–576

Theoretical study of hydrogenation of the doubly aromatic B7 cluster

  • Anastassia N. Alexandrova
  • Eldon Koyle
  • Alexander I. Boldyrev
Original Paper

DOI: 10.1007/s00894-005-0035-5

Cite this article as:
Alexandrova, A.N., Koyle, E. & Boldyrev, A.I. J Mol Model (2006) 12: 569. doi:10.1007/s00894-005-0035-5

Abstract

We have studied the influence of hydrogenation on the relative stability of the low-lying isomers of the anionic B7 cluster, computationally. It is known that the pure-boron B7 cluster has a doubly (σ- and π-) aromatic C6v (3A1) quasi-planar wheel-type triplet global minimum (structure 1), a low-lying σ-aromatic and π-antiaromatic quasi-planar singlet C2v (1A1) isomer 2 (0.7 kcal mol−1 above the global minimum), and a planar doubly (σ- and π-) antiaromatic C2v (1A1) isomer 3 (7.8 kcal mol−1 above the global minimum). However, upon hydrogenation, an inversion in the stability of the species occurs. The planar B7H2 (C2v, 1A1) isomer 4, originated from the addition of two hydrogen atoms to the doubly antiaromatic B7 isomer 3, becomes the global minimum structure. The second most stable B7H2 isomer 5, originated from the quasi-planar triplet wheel isomer 1 of B7, was found to be 27 kcal mol−1 higher in energy. The inversion in stability occurs due to the loss of the doubly aromatic character in the wheel-type global minimum isomer (C6v, 3A1) of B7 upon H2−addition. In contrast, the planar isomer of B7 (C2v, 1A1) gains aromatic character upon addition of two hydrogen atoms, which makes it more stable.

Figure

The B7H2-global minimum structure and its σ-aromatic and π-antiaromatic MOs

Keywords

Multiple aromaticity Boron hydrides Boron clusters 

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Anastassia N. Alexandrova
    • 1
  • Eldon Koyle
    • 1
  • Alexander I. Boldyrev
    • 1
  1. 1.Department of Chemistry and BiochemistryUtah State University LoganUSA

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