3.7 Optical isomerism

• Optical isomerism is a form of stereoisomerism, meaning optical isomers have the same structural formula but a different arrangement of atoms in space.
• Optical isomers are mirror images of each other and they have a chiral carbon.
• A chiral carbon is a carbon in the middle of a molecule with four different groups attached to it, which can be arranged in two different ways, forming two different molecules, known as enantiomers.
• Molecules of the chiral Center are optically active, promoting plane polarized light.
• Chiral molecules cannot superimpose.
• If a molecule is chiral, it will have two mirror images.
• Molecules with chiral centers can have the same molecular formula and functional groups, making it difficult to spot them.
• Polarized light is used to detect chiral centers.
• Chiral centers are drawn in a tetrahedral 3D shape and represented as mirror images.
• Chiral centers are identified by finding four different groups surrounding a carbon atom.
• Enantiomers are mirror images of each other and are non-superimposable, meaning they cannot be moved across each other and will not fully superimpose.
• Hands have a chiral center and are mirror images of each other.
• Racemic mixtures are often made by reacting chiral substances together.
• Optically active compounds can be identified by shining light through them and observing the rotation of plane polarized light.
• If an optically active compound is present in a solution, it will cause the plane polarized light to rotate.
• A plane polarized light is blocked by a Polaroid filter, allowing only one orientation to pass through.
• If there is an equal amount of each enantiomer in a solution, it is called Erasmus and the plane polarized light does not rotate.
• The degree of rotation of the plane polarized light is the same for both enantiomers.