Chapter 3 Flashcards
Stereochemistry
study of molecules as 3D objects
chiral
when molecules have non-superimposable mirror images
-molecules have the same chemical and physical properties, but interact differently with light
general rules for chirality
- sp3 hybridized carbon with 4 different groups
2. no plane or center of symmetry
stereoisomerism
same connectivity, different atomic orientation in space
achiral
when molecules have superimposable mirror images
stereocenters/chiral centers
- all chiral centers are stereo centers
- not all stereo centers are chiral centers
- a compound can have chirality without a chiral center
enantiomers
stereoisomers that are non-superimposable mirror images of each other (relationship)
max # of stereoisomers
2^n
racemization
interconversion of mirror images
R,S-system
set of rules for naming chiral centers
R = clockwise
S= counterclockwise
-find the 3 highest priority substituents and put the lowest one pointing away, then found the groups in order to determine whether it is clockwise or counterclockwise
1. assign priority (based on highest atomic #)
2. if a match exists one atom out from the chiral center, then move on further until priority is found
3. double and triple bonds = double and triple the atoms they are bonded to
diastereomers
stereoisomers that are not mirror images of each other
meso compound
an chiral compound possessing two or more chiral centers that have chiral isomers
Fischer projections
2D representation of a molecule; groups on the left and right are in front, while those at the top and bottom are to the rear
ordinary light
light oscillating in all planes perpendicular to its direction of propagation
plane-polarized light
light oscillating only in parallel planes
