Transient [8]Annulenyl Carbanion from the Anion Radical of Bromo-[8]annulene
| Autor: | and Matthew K. Kiesewetter, Steven J. Peters, Cheryl D. Stevenson |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry A. 108:2278-2283 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/jp036801g |
| Popis: | The anion radical of mono-bromo-[8]annulene was generated in the absence of ion association, and the EPR-measured spin densities can be explained in terms of the odd electron occupying MOs: Ψ4‘ = [2√(n2 + 1)]-1(ψ1 + nψ2 − ψ3 − nψ4 + ψ5 + nψ6 − ψ7 − nψ8) and Ψ5‘ = [2√(n2 + 1)]-1(ψ1 − nψ2 − ψ3 + nψ4 + ψ5 − nψ6 − ψ7 + nψ8) where n > 1. This anion radical subsequently disproportionates to its corresponding dianion and neutral molecule. The dianion then undergoes a loss of Br-, leaving the [8]annulenyl carbanion, which can abstract a proton from either HMPA or liquid ammonia. The pseudo-ortho-bromo-[8]annulenyl carbanion also loses Br- to give [8]annulyne, which can be stabilized in the form of its anion radical. The g value of the anion radical of [8]annulyne indicates that the extra strain energy due to the presence of the triple bond causes the two highest occupied MOs (degenerate in the anion radical of [8]annulene) to be slightly split. |
| Databáze: | OpenAIRE |
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