3.7 OPTIC ISOMERISM

Optical Isomerism (type of stereoisomerism)

occurs in carbon compounds with 4 different groups of atoms attached to a carbon. (the ‘chiral carbon atom’)

2 compounds that are optical isomers of each other are called enantiomers, they’re mirror images of each other.

racemic mixture = mixture containing 50/50 of two enantiomers.

optical isomers (rotation)

• they rotate plane polarised light in different directions.

• → One enantiomer rotates light in one direction (clock wise +) (dextrorotatory)

• and the other enantiomer rotates it by the same amount in the opposite direction (anti clockwise -) (laevorotatory)

• racemic mixture will not rotate plane-polarised light.

finding chiral C

thalidomide example

was given to preg women for morning sickness

one enantiomer was effective

one enantiomer causes birth defects