Isomers

• Isomers


  Compounds that have the same elements but different properties
• Types of isomers


  • Structural isomers
  • Geometrical isomers
  • Enantiomers
• Structural isomers


  • Differ in the covalent arrangement of their atoms
  • The number of possible isomers increases tremendously as carbon skeletons increase in size
• Structural isomers


  • CH4
  • C2H6
  • C20H42
• Geometrical isomers


  • Have the same covalent partnership but differ in spatial arrangements
  • Arise from inflexibility of double bonds
  • Single bonds allow rotation, double bonds do not
• Geometrical isomers


  • cis
  • trans
• Enantiomers


  • Isomers that are mirror images of each other
  • The middle carbon is called asymmetric carbon because it is attached to four different groups of atoms
• Enantiomers


  • Alpha-D-glucose
  • Beta-D-glucose
• Usually, one enantiomer is biologically active and the other is inactive
• Enantiomers cannot superimpose on each other
• The two enantiomers are designated L and D isomers from the Latin for left and right