A LITTLE LIGHTBULB MOMENT
Conformations, chirality and stereochemistry
Diastereomers are stereoisomers not related as mirrors
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Same family, different face, not mirror twins
The idea behind the cue
Diastereomers are stereoisomers that are not mirror images. They usually have different physical and chemical properties, which makes them easier to separate than enantiomers in achiral settings.
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Short & simple
Same family, different face, not mirror twins
Acronym
SND — Sleepy Noodles Dance.
Story
Two sock puppets wear the same costume colors but one has stripes on the sleeve and the other on the collar. They belong to the same show, but they are not mirror copies of each other.
Connect the pieces
- S (Sleepy) → Stereoisomers: These molecules have the same connectivity but differ in 3D arrangement.
- N (Noodles) → Not-mirror: They are not related as mirror images.
- D (Dance) → Diastereomers: Diastereomers are stereoisomers that are not mirror images, and they often have different physical properties.
- Sleepy · Stereoisomers: These molecules have the same connectivity but differ in 3D arrangement.
- Noodles · Not-mirror: They are not related as mirror images.
- Dance · Diastereomers: Diastereomers are stereoisomers that are not mirror images, and they often have different physical properties.
Know the limits
If a pair are mirror images, they are enantiomers, not diastereomers.
Further reading · OpenStax Organic Chemistry ↗Check your understanding
What best defines diastereomers?
A. Stereoisomers that are not mirror images of each other
B. Molecules with different atom counts
C. Any pair of constitutional isomers
D. A molecule and its exact mirror image
Reveal explanation
Stereoisomers that are not mirror images of each other
Diastereomers are stereoisomers that are not mirror images. Mirror-image pairs are enantiomers.