Английская Википедия:Butalene

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Шаблон:Chembox

Butalene is a polycyclic hydrocarbon composed of two fused cyclobutadiene rings.[1] A reported possible synthesis of it involves an elimination reaction from a Dewar benzene derivative. The structure itself can be envisioned as benzene with an internal bridge, and calculations indicate it is somewhat less stable than the open 1,4-didehydrobenzene biradical, the valence isomer in which that bridged bond is broken.

Structure and bonding

Файл:Butalene delocalized.png
Resonance is significant around the perimeter rather than through the middle.

Ab initio calculations indicate butalene has a planar geometry and, in keeping with a planar structure with 6 π-electron configuration, is aromatic. Thus, the most significant π bonding interactions involve conjugation around the periphery of the whole six-atom structure, similar to benzene, rather than cross-ring resonance along the bridging bond.[2] Significant resonance around one or the other four-membered ring alone would be a less-stable antiaromatic form, as is seen in cyclobutadiene itself.

See also

References

Шаблон:Reflist Шаблон:PAHs