- #1
Nick tringali
- 71
- 13
Click For Summary
Discussion Overview
The discussion centers around the concept of enantiomers in stereochemistry, specifically addressing the confusion some participants have regarding the structural differences that define enantiomers. The scope includes conceptual clarification and technical reasoning related to molecular structures.
Discussion Character
- Conceptual clarification, Technical explanation, Debate/contested
Main Points Raised
- One participant expresses difficulty in understanding why two molecules are considered enantiomers, stating they appear identical.
- Another participant suggests using a molecular modeling kit or visualization program to better grasp the concept of stereoisomers through 3D representations.
- A different participant elaborates on the structural differences, explaining that flipping the molecule involves specific rotations that do not yield the same configuration, thus supporting the claim that they are indeed enantiomers.
- One participant emphasizes the importance of visualizing the flipping process as akin to flipping a page in a book, rather than merely interchanging groups, to understand the stereochemical implications.
Areas of Agreement / Disagreement
Participants do not reach a consensus, as there is a clear disagreement regarding the conceptualization of enantiomers, with some expressing confusion and others providing explanations that challenge that confusion.
Contextual Notes
The discussion highlights limitations in understanding stereochemistry, particularly in visualizing molecular structures and the implications of flipping configurations. There are unresolved assumptions about the participants' familiarity with molecular modeling tools and stereochemical principles.
- #2
TeethWhitener
Science Advisor
Gold Member
- 2,630
- 2,244
Get a hold of a good molecular modeling kit or a visualization program (there are a few good free ones online). It’s a lot easier to wrap your head around stereoisomers when you can play with the 3D representations of molecules.
- #3
snorkack
- 2,388
- 536
No, they are not.Nick tringali said:
Even without getting a model - how can you flip them around one into another?
You cannot rotate it around horizontal axis - because this would flip the M-shaped carbon backbone into W. So the rotation which leaves the pentane backbone unchanged M would be the rotation around vertical axis.
But what happens to the hydroxyls then?
The upper form starts off having the left, say 2 hydroxyl group towards viewer and the right, then 4 hydroxyl group away from viewer.
When you flip the sheet, the 2-hydroxyl group will be on the right... but because you are now looking at it from the opposite side of sheet, it is now away from you. So you again have the left hydroxyl (now 4) towards you and the right hydroxyl away from you. The molecule is NOT converted to the form below where the left hydroxyl is away from you and right hydroxyl towards you.
Which is why they are enantiomers.
- #4
Mayhem
- 425
- 317
When you flip these mentally, you have to think of it as you are flipping a page of a book, not simply interchange the groups.