Is My Reasoning for Aromaticity Correct?

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SUMMARY

The discussion centers on the criteria for aromaticity, specifically regarding Huckel's Rule, which states that a compound must have 4n + 2 pi electrons to be considered aromatic. The first molecule is confirmed as aromatic due to its 6 pi electrons. The second molecule is deemed non-aromatic with 16 pi electrons. The last molecule, while having 6 pi electrons, is argued to be non-aromatic due to its non-planarity and the overlap of p-orbitals between carbonyls and oxygens, which disrupts resonance stabilization.

PREREQUISITES
  • Understanding of Huckel's Rule for aromaticity
  • Knowledge of pi electrons and their role in molecular structure
  • Familiarity with resonance stabilization in organic compounds
  • Concept of molecular planarity and its importance in aromaticity
NEXT STEPS
  • Study the implications of Huckel's Rule in various organic compounds
  • Learn about resonance structures and their contribution to stability
  • Investigate the role of molecular geometry in determining aromaticity
  • Explore examples of non-aromatic compounds and their characteristics
USEFUL FOR

Chemistry students, organic chemists, and educators seeking to deepen their understanding of aromaticity and the factors influencing it.

sashab
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Homework Statement


upload_2015-2-22_17-2-24.png


Homework Equations



Huckel's Rule: 4n +2 pi electrons

The Attempt at a Solution



I'm having problems with the last molecule. I said that the first molecule was indeed aromatic because it has 6 pi electrons and obeys the 4n + 2 rule. The second one is not aromatic because it has 16 pi electrons. But for the last molecule, my reasoning for why it's not aromatic is that although it has 6 pi electrons, the electrons in the p orbitals of the carbons from the carbonyls don't occupy the p-orbitals of the oxygen, the two p-orbitals just overlap. So I don't think the p-orbitals of those carbons count towards aromaticity in the ring because those orbitals overlap with the p-orbitals on the oxygens and not the p-orbitals of the adjacent carbons. I was thinking that those p orbitals don't contribute to resonance stabilization in the ring. There are indeed 6 pi electrons, but i don't think the conjugated pi-orbital system criteria is satisfied. Is my reasoning on the right track? Any help would be appreciated. Thanks!
 
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sashab said:

Homework Statement


View attachment 79483

Homework Equations



Huckel's Rule: 4n +2 pi electrons

The Attempt at a Solution

:[/B]

The last one is not a planar compound...my textbook says it must be a planar compound to be aromatic.
 
Last edited by a moderator:
sidarth siddhu said:
The last one is not a planar compound...my textbook says it must be a planar compound to be aromatic.
Could you please state why the last molecule is not planar? it is true that the compound must be planar to be aromatic!
 
Maybe becoz of the steric interference between NH group and oxon group it might have been diS placed. .(not so sure abt this)
 

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