Concerted reaction
Encyclopedia
In chemistry
, a concerted reaction is a chemical reaction
in which all bond breaking and bond making occurs in a single step. Reactive intermediate
s or other unstable high energy intermediates are not involved. Concerted reaction rate
s tend not to depend on solvent
polarity
ruling out large buildup of charge in the transition state
. Pericyclic reactions are concerted reactions.
In the SN2 reaction a concerted reaction also takes place. Because the reaction rate
is bimolecular there are two molecular species controlling the rate of the reaction. Because the rate is dependent on two molecules the reaction does not have any intermediate steps, only a transition state
. This means that all the bond making and bond breaking takes place in a single step. In order for the reaction to occur both molecules must be situated correctly. Therefore, the reaction is said to be concerted because it occurs in one step.
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, a concerted reaction is a chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
in which all bond breaking and bond making occurs in a single step. Reactive intermediate
Reactive intermediate
In chemistry a reactive intermediate is a short-lived, high energy, highly reactive molecule. When generated in a chemical reaction it will quickly convert into a more stable molecule. Only in exceptional cases can these compounds be isolated and stored, e.g. low temperatures, matrix isolation...
s or other unstable high energy intermediates are not involved. Concerted reaction rate
Reaction rate
The reaction rate or speed of reaction for a reactant or product in a particular reaction is intuitively defined as how fast or slow a reaction takes place...
s tend not to depend on solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
polarity
Chemical polarity
In chemistry, polarity refers to a separation of electric charge leading to a molecule or its chemical groups having an electric dipole or multipole moment. Polar molecules interact through dipole–dipole intermolecular forces and hydrogen bonds. Molecular polarity is dependent on the difference in...
ruling out large buildup of charge in the transition state
Transition state
The transition state of a chemical reaction is a particular configuration along the reaction coordinate. It is defined as the state corresponding to the highest energy along this reaction coordinate. At this point, assuming a perfectly irreversible reaction, colliding reactant molecules will always...
. Pericyclic reactions are concerted reactions.
In the SN2 reaction a concerted reaction also takes place. Because the reaction rate
Reaction rate
The reaction rate or speed of reaction for a reactant or product in a particular reaction is intuitively defined as how fast or slow a reaction takes place...
is bimolecular there are two molecular species controlling the rate of the reaction. Because the rate is dependent on two molecules the reaction does not have any intermediate steps, only a transition state
Transition state
The transition state of a chemical reaction is a particular configuration along the reaction coordinate. It is defined as the state corresponding to the highest energy along this reaction coordinate. At this point, assuming a perfectly irreversible reaction, colliding reactant molecules will always...
. This means that all the bond making and bond breaking takes place in a single step. In order for the reaction to occur both molecules must be situated correctly. Therefore, the reaction is said to be concerted because it occurs in one step.