5 Feb 2019
School
Department
Course
Stereochemistry (Lecture 13)
Chapter 5 (not 5.10) & Chapter 25 (25.2 only)
Isomers → different compounds with the same molecular formula
- Constitutional isomers → isomers with different atomic connectivities
- Stereoisomers → isomers with the same atomic connectivity but different
geometries
Chirality → “handedness”
- Objects that contain a mirror plane are achiral
- Objects that do not have a mirror plane are chiral
** A chiral object and its mirror image cannot be superimposed **
Enantiomers → chiral molecules and their non-superimposable mirror images
- The origin of chirality is the carbon atom with 4 different substituents → “chiral
centre” or a “stereocentre”
- Eg. this carbon on the right is a chiral centre → bonded to a hydrogen, OH, as
well as a C bonded to a HOCH2 and a C bonded to an OH
Enantiomers have identical properties
- Eg. melting point, pKa, density
** Then how can we differentiate between them?
- Interactions with other chiral molecules/environments
- Optical activity