Silabenzene resonance energy

Although the resonance energy of silabenzene is calculated to be about three-fourths of that of benzene, silabenzenes are extremely reactive and, thus, have been examined only in frozen matrices and in the gas phase. By far the simplest route to silabenzenes is pyrolysis of the 1,4-dihydro derivatives. 

Theoretical studies have shown that the resonance energy of silabenzene should be 2/3 that of benzene . Even though other isomers of CsHeSi such as Dewar silabenzene may be competitive in stability, silabenzene appears to have all the attributes expected for an analogue of benzene. Nevertheless, silaaromatics were for a long time thought to be elusive molecules despite the relative stability of similar heteroatomic derivatives of benzene such as phosphabenzene, arsabenzene and stibabenzene . 

The resonance energy of silabenzene has been calculated as two-thirds that of benzene. ... 

The stability of phosphabenzene and of arsabenzene in the absence of air and the isolation of the silicon-carbon and silicon-silicon double bonds might suggest that silabenzene, appropriately substituted, could be stable enough to be isolable. Indeed, calculations suggest that it would have a it-resonance stabilization energy about two-thirds that of benzene (78JA6499). 

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