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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: saint_john on September 21, 2010, 03:12:22 PM

Title: cyclic compound and its equivalent protons for the H NMR signal
Post by: saint_john on September 21, 2010, 03:12:22 PM

I say that this molecule is not aromatic because both its A and B carbons are sp³. In order for the molecule to be aromatic it cannot have sp³ carbons because it must be planar. However i am not 100 % sure about this molecule's aromaticity.

Also, i'm trying to determine which protons are chemically equivalent on this molecule for its H NMR signal. I tried to determine this by using a horizontal plane to cut the molecule in half right between the A and B carbons.
However, the wedges confuse me about this.

Title: Re: cyclic compound and its equivalent protons for the H NMR signal
Post by: sjb on September 21, 2010, 05:49:04 PM

(a picture of 3a,6a-dimethylbenzo(b)fluoranthene)



Re equivalences, what happens when you flip the system end over end, going towards you?

Title: Re: cyclic compound and its equivalent protons for the H NMR signal
Post by: orgopete on September 24, 2010, 08:16:16 AM

Compare the resonance structures.