Higher Congeners of Hexasilabenzene

Substitution of the Si atoms in SisHe by its higher congeners has a small effect on their aromatic stabilization energies i.e. the ASEs calculated according to equation 14a for 

XsHs (X = Si, Ge, Sn and Pb) are all in the range of 9-12 kcalmol . The calculated resonance stabilization energy of 39 (X = Si Y = Ge) according to equation 15 is 60.2 kcalmol identical to that of 1,3,5-trisilabenzene (12) and very similar to that of SieHe [57.8 kcalmori at MP2/ECP(d)//HF/ECP(d)] indicating the small effect of substituting three Si atoms in SieHs by C or Ge. 

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