• SDN Site Updates

    Hey everyone! The site will be down for approximately 2 hours on Thursday, August 5th for site updates.

skyisblue

Full Member
10+ Year Member
Dec 26, 2006
430
0
Status (Visible)
  1. Pre-Dental
In my book, it says that the following compound is meso. How is it meso? Where is the internal plane of symmetry? Does it even need a plane of symmetry to be meso?

First of all, my camera sucks! But being a poor student that I am, I can not upgrade so please bear with me.

The molecule is (2R,3S)-Dibromobutane. On top we have Br on the plane of the paper, CH3 with dashed lines, and H with a wedge.

On bottom, we have H with dashed lines, CH3 with a wedge and Br with solid lines.
 

Attachments

  • mesodraft.JPG
    8.1 KB · Views: 134

dantheman2007

Full Member
10+ Year Member
Jan 12, 2007
501
0
Status (Visible)
If a compound has symmetry (as this molecule demonstrates) but has chiral carbons (as this molecule also has) it's a meso compound. If you don't see it from the picture you uploaded, you can either draw the newman projection or saw horse and convert it into a fisher.
It should be more evident from these pictures, especially once you see the fisher projection.
Hope this helps.

Best,

DantheMan2007
 

CyborgNinjaX

Junior Member
10+ Year Member
Jun 15, 2006
150
0
Status (Visible)
  1. Pre-Dental
Rotate the substituents off of the C on the right. If you rotate them CW, you will see that both ends will match up with each other. There is an internal symmetry.
 
About the Ads

RENNOZ

Full Member
10+ Year Member
Jan 15, 2007
30
0
Status (Visible)
  1. Pre-Dental
2,3-dibromobutane is a meso compound b/c

1. first there's a symmetry
2. but, not all symmetrical molecules are meso compounds. the key is that all meso symmetrical cmpd have S,R or R,S configuration. It's never S,S or R,R.

i hope that helps
 

skyisblue

Full Member
10+ Year Member
Dec 26, 2006
430
0
Status (Visible)
  1. Pre-Dental
2,3-dibromobutane is a meso compound b/c

1. first there's a symmetry
2. but, not all symmetrical molecules are meso compounds. the key is that all meso symmetrical cmpd have S,R or R,S configuration. It's never S,S or R,R.

i hope that helps

Not all symmetrical molecules are meso? What? Do you have an example?

BTW, do you guys know if in order to be meso, you must have an internal plane of symmetry?
 
This thread is more than 14 years old.

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.