Siderophores:

Siderophores means iron carriers. They are small polydentate ligands that have high binding affinity towards iron. They found in high content in bacteria, fungi, and also grasses.

1. Hydroxamate siderophores:

   

2. Catecholate siderophores:

   

   

3. Mixed ligands:

Ionophores:

Ionophores are lipid soluble molecules. They transport ions across the lipid bilayers of a cell membrane.

Example: Synthetic ionophores are crown ethers, cryptands, calixarenes, etc.

Figure 7.5. Mechanism of charge transfer.