Organic Chemistry Chirality and Stereoisomers

Chiral

Objects that are not superimposable on their mirror image. Same molecular formula, same connectivity, different orientation in space are stereoisomers.

Achiral

Objects that lack chirality. The objects are superimposable on their mirror images. These objects contain either a plane of symmetry or center of symmetry.

Plane of symmetry

plane passing through an object dividing it so that one half is the mirror image of the other

Center of symmetry

a point so situated that identical components of an object are located on opposite sides and equidistant from that point along any axis passing through it.

Isomers

are different compunds with the same molecular formula.

Constitutional isomer

different connectivity

stereoisomers

same connectivity different orientations in space

Configurational isomers

differ by configuration of the substituents on an atom

Stereo center

an atom about which exchange two groups produces a stereoisomer.

Chiral center

a tetrahedral atom, most commonly carbon, that is bonded to four different groups. *all chiral centers are stereocenters but not all stereocenters are chiral centers.

Chirality can be present in molecules without chiral centers

molecules that contain no chiral centers yet are chiral due to their inability to freely rotate.

Enantiomer

Stereoisomer that is non superimposable on its on mirror image

Diastereomer

stereoisomer that is not a mirror image of the object it is rotated

2-butanol

Atropisomers

enantiomers that lack chiral center and differ because of hindered rotation substituted biphenyls.

isomers chart