Anti or non aromatic???

[jjw822]

you know pyrrole which is aromatic compound.

if the hydrogen bound to the nitrogen is not there, would it be anti or non aromatic??

and please tell me the name of that compound if you know it.

THANKS!!!

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[xhamburgersamx]

My guess is if the hydrogen bond is gone then there will be two sets of lone pairs making the total number of electons 8. Which is 4n and anti-aromatic.

 

[jjw822]

what i was thinking was that if the H is gone, it will not be in plain anymore....

but I am not SURE....

 

[Deontologist]

you know pyrrole which is aromatic compound.

if the hydrogen bound to the nitrogen is not there, would it be anti or non aromatic??

and please tell me the name of that compound if you know it.

THANKS!!!

I believe, if Hydrogen is lost as a proton leaving behind lone pair, it would still be aromatic..!! Furans and thiophenes are closely related molecules with O and S respectively in place of N. Both are still aromatic since one lone pair takes part in delocalization...!! Thats what I think...I may be wrong.

I would call such a compound, deprotonated pyrrole...lol......!!

 

[water88]

It would be aromatic, I believe. One of the lone pairs would be put into a p orbital ("rehybridize"), giving 6 pi electrons.

 

[DDS13]

if N is gone, and there is no charge or lone pair on the carbon, then it for sure is not aromatice since it does not have pi orbital, but if there is a positive charge, it is anti aromatic, since it has pi orbital but it is 4n. If it has lone pair on carbon which is not very likely, it would act as pyrole and be aromatic.

correct me if im wrong

 

[jjw822]

if you look at pyridine or pyrimidine having N with one lone pair on N with double bond coming out in one side doesn't change the fact that they are aromatic. But my question was that in pyrrole without H bound to N will still be aromatic or anti or non...

I guess I asked hard question..lol

THANKS for reply everyone. hope some crazy orgo person will come along..

 

[DDS13]

Oh in that case, FOR SURE, IT IS aromatic, because no rule is violated. I am 99.9999% sure

 

[jjw822]

Oh in that case, FOR SURE, IT IS aromatic, because no rule is violated. I am 99.9999% sure

HUM........ i cant find any info online....

BUT i am not positive but i think i had that question in my orgo..which was 2years ago... IDK....

THANKS !!!!

 

[NukeQuazar]

Oh in that case, FOR SURE, IT IS aromatic, because no rule is violated. I am 99.9999% sure

It's aromatic. 100% sure. The deprotonated lone pair in place of the sigma bond to the the proton does not change the hybridization; it's sp2, flat geometry, either way. The first lone pair remains in the p orbital, part of the conjugated cyclic system, because of the energy advantage of aromaticity. The new lone pair remains part of the sp2 hybridized system. As for the name, I don't know if there is any other name than deprotonated pyrrole.

 

[orthodocs12]

nukequazar, you are right! The original lone pair is in the pi orbital, which is in the same plane with the pi electrons of the double bond, therefor giving the number of huckels rule=6. so aromatic. When the H is plucked off, giving another lone pair on the N, the new lone pair is not counted in the conjugated system number, since it is not in the plane that makes up for the conjugation of the aromatic system.

hope that helps!