31.07 Polycyclic Aromatic Hydrocarbons and Annulenes

Benzenoid and non-benzenoid polycyclic aromatic hydrocarbons. Resonance and electron density curiosities in azulene and an oxygen-containing analogue. Annulenes and the criteria for aromaticity.

[@vinuvinu3530]

Tq soo much Sir. ..this vedio is soo heplfull😇😍

[@dlvivlviv]

As far as I understood, the oxygen of the oxaazulanone's carbonyl group is a part of a conjugated system, but not a part of the aromatic system, thus it can act as a nucleophile. Is it correct?

[@alkylpug]

I have a question, I'd be really happy if you were able to answer it even after 4 years since this video was uploaded. Its fine though if this goes unnoticed.
Pyrene has 8 double bonds right? So it has 16 pi electrons, which doesnt meet any of Huckel's rule digits. How did it become aromatic? Im just so confused and i really want this to be cleared up.

[@amanjmullick2930]

Nice teaching sir.

[@sammipanini]

Excuse me sir but are there not 12 pi electrons in the oxaazulanone 3:14

[@mevansthechemist]

True, but this molecule doesn't violate Hückel's rule as the rule applies only to cyclic hydrocarbons lacking pendant methylenes, carbonyls, and other groups that engage in conjugation with the ring. E.g. we could say that aniline (PhNH2) has eight pi electrons, but it is most definitely aromatic!

[@sammipanini]

Thank you sir! Also, your video helped me through my chem quiz this morning. Minor academic boost, immeasurable confidence reinforcement!

[@taresy6789pp]

This could be cure for covid 2019