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Author Topic: Aromatic vs Nonaromatic? This is urgent!  (Read 502 times)

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theanonymous

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Aromatic vs Nonaromatic? This is urgent!
« on: January 14, 2013, 12:36:49 PM »



Did I select the right answers?
I know that the Huckel numbers are 2, 6, 10, 14, 18, etc, pi electrons
And A only has 4 pi electrons (those 2 lines inside of it).

I need help with the other ones as well.



« Last Edit: January 14, 2013, 12:39:21 PM by Arkcon »
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theanonymous

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Re: Aromatic vs Nonaromatic? This is urgent!
« Reply #1 on: January 14, 2013, 12:48:42 PM »

Are my answers correct?

A. 4 pi electrons antiaromatic
- does not contain a Huckel number of pi electrons
- there is at least one ring atom that does not contribute a pure p-orbital to the pi system
- the species is not aromatic

B. 4 pi electrons, antiaromatic
- does not contain a Huckel number of pi electrons
- there is at least one ring atom that does not contribute a pure p-orbital to the pi system
- the species is not aromatic

C. 6 pi electrons + 2 nonbonding electrons that are not part of the pi system
- contain a Huckel number of pi electrons
- there is at least one ring atom that does not contribute a pure p-orbital to the pi system
- the species is not aromatic

D. 6 pi electrons but nonplanar molecule
- contain a Huckel number of pi electrons
- there is at least one ring atom that does not contribute a pure p-orbital to the pi system
- the species is not aromatic

E. 6 pi electrons and planar = aromatic
- contains a Huckel number of pi electrons
- there is at least one ring atom that does not contribute a pure p-orbital to the pi system
- the species is aromatic

F. 8 pi electrons, antiaromatic
- the species is not aromatic

G. 14 pi electrons, aromatic
- contains a Huckel number of pi electrons
- each ring atom contributes a pure p-orbital to make a continuous pi system
- the species is aromatic

H. 6 pi electrons, aromatic with 1 pair on nonbonding electrons not part of the pi system
- contains a Huckel number of pi electrons
- there is at least one ring atom that does not contribute a pure p-orbital to the pi system
- the species is aromatic

I. 6 pi electrons (because of the +2 charge, so 8 pi electrons - 2 = 6, which is a Huckel number), aromatic
- contains a Huckel number of pi electrons
- each ring atom contributes a pure p-orbital to make a continuous pi system
- the species is aromatic

J. 8 pi electrons, antiaromatic
- does not contain a Huckel number of pi electrons
- each ring atom contributes a pure p-orbital to make a continuous pi system
- the species is not aromatic
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amid

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Re: Aromatic vs Nonaromatic? This is urgent!
« Reply #2 on: January 14, 2013, 09:49:37 PM »

Hi,
A : NO the Boron atom has a (empty) pure p-orbital and this makes a continuous pi system.
B : OK
C : NO it is aromatic and there are only pure p-orbitals and they make a continuous pi system (S contributes to one pure pi and one pure sigma doublet, but the pure sigma does not matter in my opinion)
D : OK
E : NO as is A, there are only pure p-orbitals and they make a continuous pi system
F : NO you should add does not contain a Huckel number of pi electrons
G : ? this is complicated : as it is drawn, 2 cycles are aromatic but the right hand side on eis anti aromatic
H: NO there are only pure p-orbitals and they make a continuous pi system (as S in C, O has 1 pure-pi and 1 pure sigma doublet - and C has a pure (empty pure-pi orbital)
I : OK
J : OK
Amid
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theanonymous

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Re: Aromatic vs Nonaromatic? This is urgent!
« Reply #3 on: January 15, 2013, 03:40:08 AM »

Thanks so much!!!

I have one more quick question
I literally have 5 min to answer this. :(



A) Select all of the molecules that are aromatic
pyridine
pyrrole
imidazole
1,4-dioxine
furan


B) Select all of the molecules that contain a true lone pair.
pyridine
pyrrole
imidazole
1,4-dioxine
furan
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theanonymous

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Re: Aromatic vs Nonaromatic? This is urgent!
« Reply #4 on: January 15, 2013, 03:41:29 AM »

for part A I said pyridine and furan but they're both wrong :(
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