Flashcards in Chapter 5 Deck (30)
Different compounds with the same molecular formula
What are the two different types of isomers?
Constitutional and stereoisomers
Characteristics of constitutional isomers
- different IUPAC names
- different physical and chemical properties
Characteristics of stereoisomers
same exact molecule just different spatial arrangement of their atoms
*different from stereochemistry
to align all parts of a molecule with its mirror image
ex: right and left socks are the same shape or each other
a molecule that is superimposable
a molecule that is non-superimposable
What are the two types of stereoisomers?
Enantiomers and diastereomers
A chiral stereoisomer which mirror image is not superimposable
Stereoisomers that are not an enantiomer or a mirror image. May or may not be chiral
Define a tetrahedral stereogenic center
A carbon atom bonded to four different groups
Are cis and trans an enantiomer or a diastereomer?
ALWAYS a diastereomer
When will a molecule be achiral?
when there is no stereogenic center
If a molecule only has one stereogenic center, what is it always?
Chiral, nonsuperimposable enantiomer
If a molecule has two or more stereogenic centers, is it chiral or achiral?
Chiral centers have what type of hybridization?
What are the purpose of R and S
To differentiate between enantiomer pairs
What is the first step in labeling R and S pairs?
Label the atom with the highest atomic number as 1 and work down atomic numbers
What is rule #2 when labeling R or S
If there are two of the same atoms on the stereogenic center, the one that has branches w higher atomic numbers is higher in priority
What makes a R configuration?
-H is in the back and 1-2-3-4 is clockwise
- H is in the front and 1-2-3-4 is counterclockwise
What makes a S configuration?
- If H is in the back, and 1-2-3-4 is counterclockwise
- H is in front and 1-2-3-4 is clockwise
How do you determine the max # of stereoisomers?
2^# of chiral centers
A molecule with chiral centers but is achiral bc of mirror plane (perfect symmetry)
What is important about mesocompounds?
The only have R vs. S groups... no r v. r or s v. s
What is alpha in optical activity of chiral molecules?
Alpha is the angle of difference of light going into sample and light coming out
Rotation to the right (+)
Rotation to the left (-)
What is the same about the rotation of a R and S enantiomer?
the magnitude of alpha is the same