What is steric hindrance & steric effects?
What is steric hindrance & steric effects?
Steric effects are the effects seen in molecules that come from the fact that atoms occupy space. When atoms are put close to each other, this costs energy. The electrons near the atoms want to stay away from each other. This can change the way molecules want to react. It can also change the shape (or conformation) of the molecule. The amount of space that a group of atoms takes is called the "steric bulk". An example of steric effects is steric hindrance. This is when a large group in a molecule makes reactions not work. For example, an SN2 reaction does not happen on carbon atoms that have three substituents. Steric hindrance however can also be a positive thing. Sometimes, chemists would like a reaction to happen in one place rather than another one. A bulky group can block a position. It can also change the shape such that only one diastereomer from a reaction is made.
Steric effects are nonbonding interactions that influence the shape (conformation) and reactivity of ions and molecules. Steric effects complement electronic effects, which usually dictate shape and reactivity. Steric effects result from repulsive forces between overlapping electron clouds. Steric effects are widely exploited in applied and academic chemistry.
Steric hindrance is a consequence of steric effects. Steric hindrance is the slowing of chemical reactions due to steric bulk. It is usually manifested in intermolecular reactions, whereas discussion of steric effects often focus on intramolecular interactions. Steric hindrance is often exploited to control selectivity, such as slowing unwanted side-reactions.
Steric hindrance between adjacent groups can also affects torsional bond angles. Steric hindrance is responsible for the observed shape of rotaxanes and the low rates of racemization of 2,2'-disubstituted biphenyland binaphthyl derivatives.
Steric effects are usually smaller than electronic effects. These affect the molecule's shape and reactivity as well, but they come from the way electrons are placed in bonds.
Steric effects are the effects seen in molecules that come from the fact that atoms occupy space. When atoms are put close to each other, this costs energy. The electrons near the atoms want to stay away from each other. This can change the way molecules want to react. It can also change the shape (or conformation) of the molecule. The amount of space that a group of atoms takes is called the "steric bulk". An example of steric effects is steric hindrance. This is when a large group in a molecule makes reactions not work. For example, an SN2 reaction does not happen on carbon atoms that have three substituents. Steric hindrance however can also be a positive thing. Sometimes, chemists would like a reaction to happen in one place rather than another one. A bulky group can block a position. It can also change the shape such that only one diastereomer from a reaction is made.
Steric effects are nonbonding interactions that influence the shape (conformation) and reactivity of ions and molecules. Steric effects complement electronic effects, which usually dictate shape and reactivity. Steric effects result from repulsive forces between overlapping electron clouds. Steric effects are widely exploited in applied and academic chemistry.
Steric hindrance is a consequence of steric effects. Steric hindrance is the slowing of chemical reactions due to steric bulk. It is usually manifested in intermolecular reactions, whereas discussion of steric effects often focus on intramolecular interactions. Steric hindrance is often exploited to control selectivity, such as slowing unwanted side-reactions.
Steric hindrance between adjacent groups can also affects torsional bond angles. Steric hindrance is responsible for the observed shape of rotaxanes and the low rates of racemization of 2,2'-disubstituted biphenyland binaphthyl derivatives.
Steric effects are usually smaller than electronic effects. These affect the molecule's shape and reactivity as well, but they come from the way electrons are placed in bonds.
