Isomers

Racemic mixture

mixture of equal amounts of s and r enantiomers (non superimposable mirror images

Optically inactive

molecule that does not a net rotation of the plane of the electrical field compounds with no chiral center or meso compounds

Structural (constitutional) isomers

molecules have same molecular formula but are bonded together in different order (ie. CH3 bound to different C in each isomer)

Isomers

molecules that have the same molecular formula but have different structures

Meso compounds

molecules with internal mirror planes optically inactive due to mirror characteristic Have two chiral centers

Relative configuration

not related to absolute config. Two molecules have same relative config if they differ by only one substituent and the other substituents are oriented identically about C atom

Conformational isomers

not true isomers form of stereoisomerism in which the isomers can be interconverted exclusively by rotations about formally single bonds (refer to figure on single bond rotation) Often rapidly interconverting at room temp Different special arrangement of same molecule

Constitutional isomer

same formula with DIFFERENT connectivity around main element

Configuration

stereoisomers that can cannot be converted into one another by rotation around a single bond. The two main types of configurational isomers are geometric isomers and optical isomers

Resolution

the separation of enantiomers

Enantiomers

two conformations of a molecule when there is ONE chiral carbon occur when two or more stereoisomers have different confirmations at one or more STEREOCENTERS and are mirror images of each other but NOT superimposable (dont line up when laid on top of one another)

Trans~isomers

two groups, attached to the C of a double bond, are on the OPPOSITE side of the double bond (trans=opposite) Z

Cis~isomer

two groups, attached to the C of a double bond, are on the SAME side of the double bond (cis=same) E

Anomeric C

a stereocenter Carbs exist in both cyclic and acyclic form During cyclization, form a new stereocenter This C changes based on the direction on -OH attachment, making it either an alpha ( or beta carbon Alpha C=equatorial/axial DOWN Beta=equatorial or axial UP

Types of stereoisomers

all but constitutional

Chiral character

an atom that is attached/bonded to FOUR different types of atoms or groups

Conformers

another name for conformations isomers Can be interconverted by rotating around single bond

Stereoisomers

atoms of isomers with same molecular formula and same bond~bond connectivity but have different SPATIAL (3D) arrangements (ie. CH3 can go into page or out of page but is bound to the atoms in same way)

Optically active

compound that rotates polarized light either to the left (ccw) (-) or to the right (cw) (+)

Diastereomers

NOT mirror images and NOT superimposable occur when two or more stereoisomers have different confirmations at one or more STEREOCENTERS and are NOT mirror images of each other

Epimers

diastereomers that differ at only ONE C -if cyclize at C, form anomers

Anomers

due to anomeric c (when cyclized) cyclic monosaccharides or glycosides that are epimers, differing from each other in the configuration of C-1 if they are aldoses or in the configuration at C~2 if they are ketoses

Geometric isomers

form of stereoisomer also known as cis/trans or E~Z isomer