University Chemistry ›› 2022, Vol. 37 ›› Issue (1): 2104033.doi: 10.3866/PKU.DXHX202104033

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A Modified Hückel Molecular Orbital Model to Predict the Structure of Cyclo[2n]carbons

Yichi Zhang, Hua Hou, Baoshan Wang()   

  • Received:2021-04-13 Accepted:2021-05-06 Published:2021-05-20
  • Contact: Baoshan Wang E-mail:baoshan@whu.edu.cn

Abstract:

Hückel Molecular Orbital (HMO) theory is popular in chemistry, but it assumes that the reduced resonance integrals exist only between the nearest-neighbor carbon atoms. Such an approximation has been justified by the explicit inclusion of the resonance integrals between the meta-directing π-bonded atoms. The energy eigenvalues are obtained using the symmetry-adapted molecular orbitals, together with the extra stabilization energy due to symmetry breaking. The polyynic geometries of cyclo[2n]carbons with alternating angles are explained rationally using the modified HMO model, which gains new insights on the second-order Jahn-Teller effect for carbon rings.

Key words: Hückel molecular orbital theory, Resonance integral, Carbon ring, Symmetry, Energy level

MSC2000: 

  • G64