Chemical Forums

Please login or register.

Login with username, password and session length

Sponsored links

Pages: [1]   Go Down

Author Topic: superaromaticity?  (Read 4762 times)

0 Members and 1 Guest are viewing this topic.

a student

  • Regular Member
  • ***
  • Mole Snacks: +1/-2
  • Offline Offline
  • Posts: 78
superaromaticity?
« on: June 16, 2010, 05:35:41 AM »

what does superaromaticity means ???
Logged

demoninatutu

  • Chemist
  • Regular Member
  • *
  • Mole Snacks: +7/-1
  • Offline Offline
  • Posts: 30
Re: superaromaticity?
« Reply #1 on: June 17, 2010, 05:16:30 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.
Logged

a student

  • Regular Member
  • ***
  • Mole Snacks: +1/-2
  • Offline Offline
  • Posts: 78
Re: superaromaticity?
« Reply #2 on: June 17, 2010, 09:32:07 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.
so naphthalene can be superaromatic? am I right?
Logged

a student

  • Regular Member
  • ***
  • Mole Snacks: +1/-2
  • Offline Offline
  • Posts: 78
Re: superaromaticity?
« Reply #3 on: June 22, 2010, 05:59:11 AM »

is the number of fused rings important? ???
Logged

Mitch

  • In Vivo Chemist
  • Administrator
  • Sr. Member
  • *
  • Mole Snacks: +352/-81
  • Offline Offline
  • Gender: Male
  • Posts: 5003
  • "I bring you peace." -Mr. Burns
    • Chemistry Blog
Re: superaromaticity?
« Reply #4 on: June 22, 2010, 01:38:49 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.
Logged
Most Common Suggestions I Make on the Forums.
1. Always start by writing a balanced chemical equation.
2. Don't confuse thermodynamic stability with chemical reactivity.
3. Forum Supports LaTex

tamim83

  • Retired Staff
  • Full Member
  • *
  • Mole Snacks: +67/-7
  • Offline Offline
  • Gender: Female
  • Posts: 395
  • Quantum Kitten
Re: superaromaticity?
« Reply #5 on: June 22, 2010, 03:53:29 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. 
Logged

demoninatutu

  • Chemist
  • Regular Member
  • *
  • Mole Snacks: +7/-1
  • Offline Offline
  • Posts: 30
Re: superaromaticity?
« Reply #6 on: June 22, 2010, 05:30:43 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.


Logged

tritiger

  • New Member
  • **
  • Mole Snacks: +0/-0
  • Offline Offline
  • Posts: 4
Re: superaromaticity?
« Reply #7 on: July 05, 2010, 02:30:23 AM »

maybe like superconjugation

C60 and 70 are two examples?
Logged

MissPhosgene

  • Chemist
  • Full Member
  • *
  • Mole Snacks: +23/-5
  • Offline Offline
  • Gender: Female
  • Posts: 364
Re: superaromaticity?
« Reply #8 on: September 16, 2010, 06:00:14 PM »

Mitch, What's superconjugation?  ;)
Logged
Stereograms of the 32 crystallographic point groups: little bike wheels of cold, hard, pure rationality.

Jorriss

  • Chemist
  • Full Member
  • *
  • Mole Snacks: +41/-14
  • Offline Offline
  • Posts: 524
Re: superaromaticity?
« Reply #9 on: September 16, 2010, 07:17:03 PM »

I would expect benzene to be superaromatic? It has more stabilization through conjugation than anything else right?
Logged
Pages: [1]   Go Up
 

Mitch Andre Garcia's Chemical Forums 2003-Present.

Page created in 0.065 seconds with 23 queries.