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I have read about non-huckel double bonds and clar's rule, but what made me confuse is that huckel's perception gives me the feeling that central bonds in polycyclic aromatic hydrocarbons (ex: pyrene) is simply minimally affecting aromaticity or even dropped off, while clar's rule shows different resonance forms which in total makes a complete sextet formed in each ring of pyrene.

  1. So how could i resolve this issue?

  2. what would happen to aromaticity if simply the central double bond was not in the pyrene?

  3. is there any cross-conjugation involved? and how would cross-conjugation affect aromaticity?

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  • $\begingroup$ have you seen chemistry.stackexchange.com/questions/16562/… $\endgroup$ Commented Aug 19, 2020 at 14:47
  • $\begingroup$ @AniruddhaDeb Yes but the answers don't show the way both rules (clar and huckel) are applicable in the same molecule (pyrene) although they don't seem so. And they don't show the effect of central double bonds on stability as well as aromaticity and whether cross-conjugation is involved or not? $\endgroup$
    – mohamed
    Commented Aug 19, 2020 at 16:47

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