Flashcards in Organic Chemistry Isomers and Structure Deck (19):
What is the formula for saturation?
[2(C)+ N - H - X + 2] / (2)
What position, on cyclic molecules, provides more stability for large molecules?
Large molecules are stabilized on the equatorial position.
What are Constitutional isomers (structural isomers) ?
Constitutional, or structural, isomers are molecules that have the exact same molecular formula, but the arrangement of the atoms are different. You can tell molecules are these isomers because their name will be different, even with the same atoms.
Structural isomers also have different physical and chemical properties.
What are Confomer isomers?
Conformers are essentially the same molecules, however they differ by a rotation via a sigma bond.
What are geometrical isomers?
Geometerical isomers differ by the orientation in space and can not be rotated around the pi bond. Identified with E & Z configurations.
What are optical isomers?
Optical isomers differ in the orientation in space. No matter how you turn the molecules, they are not superimposable on themselves, therefore are mirror images.
What position is the most stable for conformational isomers?
The anti position, where the most substituted molecules are far away from each other is the most stable position.
IF there are molecules that have the ability to hydrogen bond with each other, then the gauche position in the most stable.
What are meso compounds?
Meso compounds are molecules which have chiral centers, but they are also symmetrical. This means they can not rotate plan polarized light.
What is the equation to calculate the number of stereoisomers?
2^n where n are all the chiral carbons.
What are enantiomers?
Enantiomers are non-superimposable mirror images.
Enantiomers have a different Cahn- Ingold value at every single chiral carbon. These molecules also have very similar physical and chemical properties, but rotate plane polarized light differently.
What are the values for optical activity?
D rotates light in a clockwise manner and is labeled with +
L rotates light in a CCW manner and is labeled with -
THIS IS NOT THE SAME THING AS R AND S.
What is a racemic mixtures?
Equal parts of the R and S enantiomer. Because it is of equal parts, the optical activity cancels itself out and the net optical activity is zero.
What are Diastereomers?
Diastereomers are non mirror images. There is AT LEAST one chiral center that stays the same. Diastereomers are different physical and chemical properties.
What is relative configuration?
Removing one functional group for another, but the other three remain the same. If this is the case, then the two are considered to be relative configurations.
How are geometric isomers and diastereomers related?
Geometric isomers are a subclass of diastereomers. So, if you find a geometric isomer then it is also a diastereomer.
What does a 120 degree angle represent in a newman projection in relation to substituents?
It represents the eclipsed position.
What does a 180 degree angle represent in a newman projection in relation to substituents?
It represents the anti position.
What does a 60 degree angle represent in a newman projection in relation to substituents?
It represents the gauche position.