Is Tropolone Aromatic Despite Its Unusual Structure?

[themonk]

I understand the rules of aromaticity, but I do not understand why Tropolone is aromatic. The main reason is because I thought all the atoms in the ring have to have p-orbitals. How does the C connected the oxygen with a double bond have a p-orbital? Have to do with the resonance (that's my main guess)?

It passes Hückel's rule with 6e- pi electrons and also passes other criteria.

 

[DrDu]

Whether a C-atom "has" a p-orbital or not is a question of definition. How would you test experimentally if Tropolone is aromatic because you are so sure about it?

 

[DDTea]

You touched on the Hueckel rule for aromaticity but not the full definition: 4n + 2 pi electrons in a conjugated, cyclic system. Yes, this does meet that criteria.

Why do you think the carbonyl C does not have a p-orbital? There is a pi bond between C and O, so how can it not have p orbital? Can you explain more clearly what you think the problem is?

 

[themonk]

Whether a C-atom "has" a p-orbital or not is a question of definition. How would you test experimentally if Tropolone is aromatic because you are so sure about it?

You can do NMR Spectronomy for a good result to see if it is Aromatic.

Why do you think the carbonyl C does not have a p-orbital? There is a pi bond between C and O, so how can it not have p orbital? Can you explain more clearly what you think the problem is?

I understand now that C and O have a pi bond because they have a double bond between each other. I just wasn't thinking because it was late. So then there are pi bonds on all the Carbons, creating a continuous lobed structure. I was just was not thinking enough about how pi bonds form.

Thanks for your help DrDu and DDTea.

 

[LudusRex]

The aromaticity of tropolone is due to a combination of factors, including the presence of p-orbitals on all of the atoms in the ring and the delocalization of pi electrons through resonance. The carbon atom connected to the oxygen in the double bond has a p-orbital that participates in the delocalized pi system, allowing for the ring to meet the criteria for aromaticity. This delocalization of pi electrons through resonance helps to stabilize the ring and give it its characteristic aromatic properties. Additionally, as you mentioned, tropolone also meets Hückel's rule for aromaticity, with 6 pi electrons in the ring. This combination of factors is what makes tropolone aromatic.