Isomers Flashcards
What are enantiomers?
nonsuperimposable mirror images: have opposite configurations at every chiral center in the molecule
What is the only type of isomers that have equal but opposite optical activities: they rotate plane-polarized light in opposite directions?
Enantiomers
How do you calculate the specific rotation of a compound?
specific rotation = [alpha] = alpha observed / (c . l )
c = concentration in g/ml or mol/L
l = path length in dm
What is the difference between conformational and configurational isomers?
conformational: can interconvert by simple bond rotation
configurational: can only interconvert by breaking and reforming covalent bonds
What are diastereomers?
when molecules have 2 + stereocenters and differ at some, BUT NOT ALL
Do enantiomers have similar or different chemical and physical properties
Similar
Do diastereomers have similar or different chemical and physical properties
Different
What type of isomers are cis/trans isomers?
Diastereomers
What type of isomers are epimers?
Diastereomers
What are 2 types of configurational isomers?
Enantiomers and diastereomers
What happens to the observed rotation if you decrease the concentration?
Decrease because an optically active substance at a given temperature has only one value for the specific rotation
What is a mutarotation? What type of isomers result?
The spontaneous change of configuration at the C1 of a hemiacetal
Anomers
What is an exception to the 2^n number of stereoisomers rule?
Tartaric acid
What kind of isomers does tautomerization create?
Constitutional isomers
What are anomers?
A type of epimers
