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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Rutherford on May 04, 2013, 07:55:39 AM

Title: Aromaticity (complex compounds)
Post by: Rutherford on May 04, 2013, 07:55:39 AM

How is the attached compound aromatic? I can't see the conjugated system expanding from the three benzene rings. They look to me like separated with two sigma bonds from each other. Need an explanation.

Title: Re: Aromaticity (complex compounds)
Post by: Dan on May 04, 2013, 10:34:55 AM

The compound has three aromatic rings, but as you point out they are not conjugated with each other. For a compound to be aromatic it need as least one aromatic system, but it could have more.

Title: Re: Aromaticity (complex compounds)
Post by: Corribus on May 04, 2013, 12:10:00 PM

Compounds like this are thought to manifest a special type of aromaticity called Mobius aromaticity.

See: http://en.wikipedia.org/wiki/M%C3%B6bius_aromaticity

The prototype compound, very similar to the one you have here, is barrelene:

http://en.wikipedia.org/wiki/Barrelene

Title: Re: Aromaticity (complex compounds)
Post by: Rutherford on May 04, 2013, 01:32:10 PM

Thanks for the help.