What is the Difference Between Oxidative Addition and Reductive Elimination?

Oxidative addition and reductive elimination are two types of reactions that involve a change in the oxidation state and coordination number of a metal center in a coordination complex. They are related processes, but they have opposite effects:

Oxidative Addition:

• Involves the addition of two anionic ligands to a metal center.
• Results in an increase in the oxidation state and coordination number of the metal.
• Facilitated by electron-rich metal centers having low oxidation states.
• Commonly observed for four- and five-coordinate complexes, as they have vacant coordination sites.
• Often occurs in catalytic cycles, in conjunction with its reverse reaction, reductive elimination.

Reductive Elimination:

• Involves the removal of two anionic ligands from a metal complex.
• Results in a decrease in the oxidation state and coordination number of the metal.
• Facilitated by electron-poor metal centers having high oxidation states.
• Intramolecular reaction, favored by low electron density of the metal.
• Ligands must be in a cis position in order to undergo reductive elimination.

These two reactions are crucial in various applications, such as catalytic cycles and product-releasing steps in several reactions that form C-H and C-C bonds.

Comparative Table: Oxidative Addition vs Reductive Elimination

Here is a table comparing oxidative addition and reductive elimination:

Oxidative addition and reductive elimination are reaction pairs that involve a change in the oxidation state and coordination number of the metal in a coordination complex.