Here’s a explanation of how chirality arises in coordination complexes:
1. What is chirality?
- A molecule is chiral if it cannot be superimposed on its mirror image, just like your left and right hands.
- Chiral molecules can exist as two mirror-image forms, called enantiomers.
2. How it happens in coordination complexes
Chirality occurs when the arrangement of ligands around a metal creates asymmetry.
A. Octahedral complexes with bidentate ligands
- If a metal has three bidentate ligands (ligands that attach at two points), the way they wrap around the metal can make the complex non-superimposable on its mirror image.
- These are called Λ (lambda) and Δ (delta) forms, which are right- and left-handed.
B. Tetrahedral complexes
- If a tetrahedral complex has four different ligands, the arrangement can be chiral.
- Example: a metal with four different ligands arranged tetrahedrally forms a chiral center, like carbon in organic molecules.
3. Key Points
- Chirality arises due to asymmetric arrangement of ligands around the metal.
- Chiral coordination complexes can rotate plane-polarized light, which is important in pharmaceuticals and biochemistry.