optical isomerism

What is a chiral carbon?

A carbon with four different groups attached to it

What are enantiomers?

Two non superimposable mirror image structures caused when the groups around a chiral carbon are arranged differently

How do optical isomers differ in their effect on plane polarised light?

Normal light vibrates in all directions while plane polarised light vibrates in one direction only. Optical isomers are optically active meaning they rotate plane polarised light. One enantiomer rotates plane polarised light clockwise while the other enantiomer rotates it anticlockwise by the same angle

What is a racemic mixture?

is an optically inactive mixture that contains equal amounts of two enantiomers. They are optically inactive as the effect on light of each isomer cancels out

How do you draw optical isomers?

Draw in 3D

Which prefixes are used to name isomers?

If an optical isomer rotates light to the left its given - or L

If an optical isomer rotates light to the right its given + or D

How do optical isomers effect drug synthesis?

Drug synthesis is started often from synthetic compounds that are a mixture of optical isomers. This can mean that one optical isomer will be the active drug but the other could be inactive or poisonous. To prevent this some drugs are manufactured from compounds with only one optical isomer. During synthesis the optical isomerism doesnt change from reactants to products.

What are isomers?

Compounds with the same molecular formula but different molecular structures

What are stereoisomers?

Where two or more compounds have the same structural formula but differ in the arrangement of the bonds in space. Either E-Z isomerism or optical isomerism

When do optical isomers occur and what do they form?

When there are four different substituents attached to one carbon atom. This results in two isomers that are non superimposable mirror images of one another but are not identical

What does a polaroid do?

Cuts all the light vibrations out except those in one plane

What can optical rotation be measured using?

A polarimeter

3 steps of using a polarimeter?

1. Polarised light is passed through the two solutions of the same concentration each containing a different optical isomer of the same substance

2. One solution will rotate the plane of polarisation through a particular angle, clockwise. This is the + isomer

3. The other will rotate the plane of polarisation by the same angle anticlockwise. This is the - isomer