Stereochemistry Flashcards

Flashcards covering key vocabulary related to stereochemistry.

Stereochemistry

The chemistry of molecules in three dimensions.

Isomers

Different compounds with the same molecular formula.

Constitutional Isomers

Different compounds with the same molecular formula but differ in the nature or sequence of bonding.

Stereoisomers

Isomers that differ only in the way the atoms are oriented in space. They have identical IUPAC names (except for a prefix like cis or trans) and the same functional group(s).

Configuration

A particular three-dimensional arrangement of atoms in a molecule.

Conformational Isomers (Conformers)

Isomers that interconvert easily by rotation about single bonds.

Configurational Isomers

Isomers that interconvert only with difficulty and usually require bond breaking.

Chirality

A property of a molecule that is not superimposable on its mirror image.

Chiral Molecule

A molecule that is not superimposable on its mirror image.

Achiral Molecule

A molecule that is superimposable on its mirror image (lacking chirality).

Stereogenic Center

A carbon atom with four different groups attached, often a chiral center.

Enantiomers

Non-superimposable mirror image stereoisomers.

Plane of Symmetry

A mirror plane that cuts the molecule in half, so that one half of the molecule is a reflection of the other half; its presence generally makes a molecule achiral.

Diastereomers

Sterio isomers that are not mirror images of each other . Non-mirror image stereoisomers that occur when more than one chiral center is present in a molecule.

R and S system

A system of assigning stereochemical configurations using the Cahn-Ingold-Prelog priority rules.

Cahn-Ingold-Prelog system

Naming enantiomers with the prefixes R or S.

Dextrorotatory

A chiral compound that rotates plane-polarized light clockwise (to the right), labeled d or (+).

Levorotatory

A chiral compound that rotates plane-polarized light counterclockwise (to the left), labeled l or (-).

Racemic Mixture (Racemate)

An equal amount of two enantiomers, which is optically inactive.

Specific Rotation

A standardized physical constant for the amount that a chiral compound rotates plane-polarized light.

Optical Activity

The property of chiral compounds to rotate the plane of polarized light.

Meso Compound

An achiral compound that contains stereogenic centers and a plane of symmetry.

Nitrogen Inversion

Rapid inversion of amines that makes them achiral.

Fischer projection

representation of a three-dimensional molecule as a flat structure.