Ochem Isomers

Isomers

same molecular formula but differ in some way

Constitutional Isomers

same formula, different connectivity

Configurational Isomers

differ in dash/wedge

Diastereomers

• not mirror image

• opposite configuration at some chiral centers

  • at least one stays the same

  • changing one points dashes or wedges to the opposite

• E (trans) & Z (cis)

Z and E

Z: cis (highest priorities on the same top, or same bottom)

E:trans (highest priority on opposite ends of a molecule) — prob a double carbon

Stereo isomers

same formula and connectivity BUT different 3D structure

Conformers

differ only by rotations of single bonds

Enatiomers

Isomers that are a mirror image (think of hand)

• molecules that are not identical to mirror image

• nonsuper imposable

• draw the mirror image (flip like turning hand over)

• OR

• interchange two of the groups (dash/wedge)

• all chiral centers switch

• R & S

R and S

R: priorities 1-3 moving clockwise around the chiral center

S: priorities 1-3 moving counterclockwise around the chiral center

• if lowest priority is a dash/hidden H —> forget about it

Nonsuper imposable

• Two molecules cannot overlap perfectly, no matter how you rotate them.

• Their 3D arrangements are different.

• This is an important property of enantiomers.

Example: Your left hand and right hand.

Superimposable

• Two molecules can overlap perfectly.

• Every atom lines up with the corresponding atom.

• You can rotate the molecules to make them match.

Example: Your left hand placed on another left hand.