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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: a student on June 16, 2010, 11:35:41 AM

Title: superaromaticity?
Post by: a student on June 16, 2010, 11:35:41 AM
what does superaromaticity means ???
Title: Re: superaromaticity?
Post by: demoninatutu on June 17, 2010, 11:16:30 PM
Superaromaticity is where the aromaticity is spread over a number of fused or conjugated rings. It's surprisingly not found in C60, which one would expect to be superaromatic because it's made solely of fused rings.
Title: Re: superaromaticity?
Post by: a student on June 18, 2010, 03:32:07 AM
Superaromaticity is where the aromaticity is spread over a number of fused or conjugated rings. It's surprisingly not found in C60, which one would expect to be superaromatic because it's made solely of fused rings.
so naphthalene can be superaromatic? am I right?
Title: Re: superaromaticity?
Post by: a student on June 22, 2010, 11:59:11 AM
is the number of fused rings important? ???
Title: Re: superaromaticity?
Post by: Mitch on June 22, 2010, 07:38:49 PM
Superaromaticity is where a group of physical organic chemistry professors brag how large their penises are in comparison to their colleagues at national chemistry conferences, as described by my old professor.
Title: Re: superaromaticity?
Post by: tamim83 on June 22, 2010, 09:53:29 PM
Quote
It's surprisingly not found in C60, which one would expect to be superaromatic because it's made solely of fused rings.

Doesn't surprise me; C60 is not planar so there really can't be very much pi delocalization going on. 
Title: Re: superaromaticity?
Post by: demoninatutu on June 22, 2010, 11:30:43 PM
Quote
so naphthalene can be superaromatic? am I right?

Having looked at it a bit further the term 'superaromatic' doesn't seem to be quite as well defined as aromaticity. There don't appear to be many publications that reference it and it doesn't appear at all in my (i.e I own it, I didn't write it) otherwise comprehensive textbook on Physical Organic Chemistry.

'Aromaticity' is well defined by Huckel's rule but 'superaromaticity' seems to be a fluffy term related to extra stabilisation that one could expect from a highly extended conjugated ring system over and above an extended linear one. More precisely, it seems to have been most applied to ring systems made exclusively of fused or interconnected benzene rings.

In Aihara, Chemical Physics Letters Volume 381, Issues 1-2, 4 November 2003, Pages 147-153 this definition is presented:

'By superaromaticity we mean aromatic stabilization due to cyclic motion of π-electrons along the macrocycle'

Since naphthalene is not a macrocycle, it would not be considered to be 'superaromatic'. Though this appears to be simply a question of nomenclature, rather than being based on any physical/chemical principles.


Title: Re: superaromaticity?
Post by: tritiger on July 05, 2010, 08:30:23 AM
maybe like superconjugation

C60 and 70 are two examples?
Title: Re: superaromaticity?
Post by: MissPhosgene on September 17, 2010, 12:00:14 AM
Mitch, What's superconjugation?  ;)
Title: Re: superaromaticity?
Post by: Jorriss on September 17, 2010, 01:17:03 AM
I would expect benzene to be superaromatic? It has more stabilization through conjugation than anything else right?