Chirality Flashcards
Meso Compounds
All meso compounds have multiple chiral centers, but are not optically active overall
Chiral compounds
Mirror image is distinct and not superimposable
Achiral compound
Mirror image and molecule are identical
Enantiomers
Pair of non-superimposable mirror images with the same connectivity
Sterocenter
An atom bound to at least 4 unique groups
R/S system
We assign priority to each substituent connected to the chiral atom based off of atomic number
Lowest priority substituant
Must be pointing into the page. If out, flip the molecule on a vertical axis
R
Clockwise
S
Counterclockwise
d/l system
How the molecule rotates plane-polarized light
d
Rotates light in clockwise direction
l
rotate light in counterclockwise direction
Specific rotation equation
observed optical rotation/
concentration of solution * length (dm)
What is the rotation of light when there is a racemic mixture of two enantiomers?
- This is because their opposite rotations cancel each other out
Enantiomeric excess
(observed optical rotation/ specific rotation) * 100
D/L system
used to classify monosaccharides and amino acids (L)
D/L system
used to classify monosaccharides (D) and amino acids (L)
Stereoisomers
Every chiral center with two possible configurations doubles the number of possible stereoisomers for a given molecule
2^n
“n” being the number of chiral centers in the molecule
Diastereomers
Not mirror images. There can be multiple for one molecule
Epimers
Stereoisomers differing at just one chiral center
Anomers
cyclic
Achiral molecules contain…
Contain an internal plane of symmetry and are also known as meso compounds
Differing at chiral center rules
Enantiomers- if both chiral centers have different configurations
Diastereomers- if only one of the two chiral centers has a different configuration
