Chapter 2: Isomers Flashcards
What are isomers?
Isomers are molecules that have the same molecular formula, but different structures
What are some examples of physical properties?
Mellting point, boiling point, solubility
What are some examples of chemical properties?
How the compound reacts
What type of isomers are most different from each other?
Structural (constitutional isomers) are the most different
They have completely different chemical and physical properties
What are stereoisomers?
They are isomers that share the same chemical formula and atomic connectivity. They only differ in how the atoms are arranged in space.
Geometric isomers, enantiomers diastereomers, meso compounds and conformational isomers are all subtypes of stereoisomers
What are geometric isomers?
Compounds that differ in the position of substituents attached to a double bond or cycloalkane
“cis”/”trans”
Describe the Z/E convention for naming complicated polysubstituted double bonds
Z: if the two highest-priority substituents on each carbon are on the same side of the double bond
E: if the two highest-priority substituents on each carbon are on the opposide side of the double bond
Z = “z”ame side
What does chiral mean?
An object that is not superimposable upon its mirror image
What are enantiomers?
The nonsuperimposable mirror images of chiral objects
What is the difference between relative and absolute configurations?
Relative: the configuration of a chiral molecule in relation to another chiral molecle
Absolute: The exact spatial arrangement of these atoms or groups, independent of other molecules
Describe how to determine the absolute configuration of a molecule at a single chiral center
1) Assign priority to the 4 substituents
2) Orient the molecule in space so that the atom with lowest priority is at the back
3) Draw a circle connecting substituents from 1 to 2 to 3
4) If circle is clockwise, then the chiral center is R. If the circle is counterclockwise, then the chiral center is S
