Solving Resonance Structures of NH2OH Conjugate Base

In summary, the conversation discusses the process of drawing resonance structures for a given compound. The compound in question is a conjugate base and the conversation explores different possible resonance structures, including one with a proton removed from the alcohol group and another with a proton removed from the amine group. Ultimately, it is determined that the compound is a fancy phenol and the correct resonance structure involves removing a proton from the ring.
  • #1
smithnh
11
0
[SOLVED] Resonance Structures

1. Homework Statement [/b]

Draw the major resonance contributors that show electron delocaliztion of the formal charge for the following ions,

The conjugate base of
.O
.||... NH2
/..\ /...\\ /
...||...|
... \...//\
....OH

3. The Attempt at a Solution [/b]

Possible conjugate bases

.O
.||...NH2
/..\ /...\\ /
...||...|
...\...//\
....O(-) However this has no resonance structures...

.O
.||...NH(-)
/..\ /...\\ /
...||...|
...\...//\
....OH However this has no resonance structures...

and finally...
...O
...||...NH2
...(-)/ \ /...\\ /
...||...|
...\...//\
......OH with the resonance structure...

... O (-)
...|...NH2
...//..\ /..\\ /
...||...|
...\...//\
.....OH

am I on the right track with the last answer?
 
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  • #2
Sorry, I have no idea what you are trying to do here. Is it possible to put the compound on a single line? (-O-N(+)H2-OH, for example)
 
  • #3
I have a better idea, go to this link
(It's the first part of problem 2)

http://orgchem.colorado.edu/courses/imagesbhS08/HW1_3331sp08.pdf"

What I tried to do was first remove an H+ from the alcohol but it does not have any resonance contributors, then I tried to remove an H+ from the amine group but the same result. Finally, I tried to remove a hydrogen from the methyl group next to the ketone which does have a resonance structure but I do not know if that is correct.
 
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  • #4
It asks for the conjugate base, so we're obviously talking about an acidic proton. This molecule is just a fancy phenol (an acid). Remove the proton there and look at ALL of the possible resonance structures.
 
  • #5
Thanks for your help, I see now that the electrons can move into the ring without breaking the phenyls aromaticity.
 

1. What is a resonance structure?

A resonance structure is a possible arrangement of atoms within a molecule, where the placement of electrons can be represented by different Lewis structures. These structures differ in the placement of double bonds and lone pairs, but the overall arrangement of atoms remains the same.

2. Why is it important to consider resonance structures?

Resonance structures show the delocalization of electrons in a molecule, which can greatly impact its stability and reactivity. By considering all possible resonance structures, we can better understand the chemical properties and behavior of a molecule.

3. How do you solve for resonance structures of NH2OH conjugate base?

To solve for resonance structures of NH2OH conjugate base, start by drawing the Lewis structure for NH2OH. Then, move a lone pair from the nitrogen atom to form a double bond with the oxygen atom. This creates the first resonance structure. Next, move a lone pair from the oxygen atom to form a double bond with the nitrogen atom. This creates the second resonance structure. Finally, move the double bond between the nitrogen and oxygen atoms to create a third resonance structure.

4. What are the major and minor resonance structures of NH2OH conjugate base?

The major resonance structure of NH2OH conjugate base is the one where the negative charge is on the oxygen atom, as oxygen is more electronegative than nitrogen. The minor resonance structures are the ones where the negative charge is on the nitrogen atom, as this is a less stable arrangement.

5. How does the concept of resonance affect the acidity of NH2OH conjugate base?

The delocalization of electrons in resonance structures of NH2OH conjugate base results in a stabilization of the negative charge. This makes the molecule more stable and less likely to donate a proton, making it a weaker base. Therefore, resonance decreases the acidity of NH2OH conjugate base.

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