14.1: Reactions Involving Gain or Loss of Ligands
- Page ID
- 392515
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Many reactions of organometallic complexes involve change in coordination number. In a dissociation reaction, one or more ligands are eliminated from the complex and the coordination number decreases. In an association, one or more ligands are added to the complex and the coordination number increases. If the coordination number changes while the metal oxidation state remains constant, the reactions are considered association/addition reactions or dissociation reactions. Reactions can also occur where the coordination number changes while the metal oxidation state also changes. These reactions are considered reductive eliminations or oxidative additions (or a combination of these).
- Association or Addition Reaction: a reaction in which the coordination number increases; metal oxidation state is unchanged.
- Dissociation Reaction: a reaction in which the coordination number decreases; metal oxidation state is unchanged.
- Oxidative Addition: a reaction in which coordination number increases while metal oxidation state increases.
- Reductive Elimination: a reaction in which coordination number decreases while metal oxidation state decreases.
- 14.1.1: Ligand Dissociation and Substitution
- ligand substitution involves the exchange of one ligand for another, with no change in oxidation state at the metal center. The incoming and outgoing ligands may be L- or X-type, but the charge of the complex changes if the ligand type changes. Keep charge conservation in mind when writing out ligand substitutions.