Bidentate ligands

Definition

Bidentate ligands are molecules or ions that can form two bonds to a central metal atom in a coordination complex. They have two donor atoms that each share an electron pair with the metal center.

5 Must Know Facts For Your Next Test

1. Bidentate ligands increase the stability of coordination complexes through the chelate effect.
2. The most common example of a bidentate ligand is ethylenediamine (en), which has two nitrogen atoms that can coordinate with a metal center.
3. Bidentate ligands can form five-membered or six-membered rings when they bind to metals.
4. In naming coordination compounds, bidentate ligands are often indicated by prefixes such as 'bis-' for two, 'tris-' for three, and so on.
5. Bidentate ligands are crucial in many biological systems, such as hemoglobin, where they facilitate oxygen transport.

Review Questions

• What is the chelate effect and how does it relate to bidentate ligands?
• Give an example of a common bidentate ligand and explain how it binds to a metal center.
• Why do bidentate ligands generally form more stable complexes compared to monodentate ligands?

Related terms

Chelation: The process of forming a ring structure by binding multiple points on the same ligand to a metal ion.

Coordination Number: The number of ligand donor atoms bonded to the central metal atom in a coordination complex.

Monodentate Ligand: A ligand that donates only one pair of electrons to form one bond with the central metal ion.