Why thiophene is more aromatic than furan

A must visit No need to find colleges in other sites, this is the best site in India to know about any colleges in India. Home QnA Home explain the stability between furan ,pyrrole and thiophene. Get answers from students and experts Ask. Lucky Patil 22nd Sep, Answer later. Aman Ghatiya 22nd Sep, Hello Lucky Patil , Since N is less electronegative than O, it will be slightly more stable than O with that positive charge.

Hence, pyrrole will be more aromatic than furan. Share Facebook Copy Link. More Report. Delete Answer. Gaurang Tandon. Gaurang Tandon Gaurang Tandon 8, 10 10 gold badges 55 55 silver badges bronze badges. Empirically, though, pyrrole and furan undergo dearomatisation fairly easily because they're very electron-rich; thiophene has more benzene-like reactivity because it's less electron-rich sulfur 3p poorer overlap with carbon 2p.

Regarding thiophene, furan and pyrrole, in thiophene due to the lesser electronegativity of sulphur, the lone pair delocalises easily, and so aromatisation is better. I have no idea about how to include pyrridine among these. Also aromaticity is not a well enough defined concept to actually derive an order. You can evaluate their reactivity with respect to different mechanisms, but then you are comparing exactly that, and you are only deducing properties towards aromaticity.

How could you quantify something that you can't really measure? When you compare hydrogenation among those compounds, you do exactly that, you don't actually measure aromaticity. So with respect to aromaticity, these are all guesses; with respect to reactivity it is data, and that is in principle what you want to know.

If you know which compound is "more aromatic" , but it doesn't let you deduce which reactions it will undergo more than the other, then that is basically a pointless characteristic, designed to generalise.

We already know that these approaches might lead to wrong conclusions. Show 6 more comments. Active Oldest Votes.

Improve this answer. Oscar Lanzi Eldar Eldar 2 2 bronze badges. Add a comment. So , all the four carbon atoms and the heteroatom are in the same plane. They all have an aromatic sextet i.

These electrons are in the unhybridized p-orbital of each atom- perpendicular to the plane of the ring. The double bonds and the lone pair involved in the sextet are in conjugation as shown below- All structures are cyclic. The next structures have a positive charge on N and the negative charge and double bonds alternate with each other as shown below- Similar resonating structures can be written for furan and thiophene. In the next post we will continue talking about some more heterocyclic compounds.

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