Inorganic Chemistry Lesson of the Day – 2 Different Ways for Chirality to Arise in Coordination Complexes
June 26, 2014 Leave a comment
In a previous Chemistry Lesson of the Day, I introduced chirality and enantiomers in organic chemistry; recall that chirality in organic chemistry often arises from an asymmetric carbon that is attached to 4 different substituents. Chirality is also observed in coordination complexes in inorganic chemistry. There are 2 ways for chirality to be observed in coordination complexes:
1. The metal centre has an asymmetric arrangement of ligands around it.
- This type of chirality can be observed in octahedral complexes and tetrahedral complexes, but not square planar complexes. (Recall that square planar complexes have a plane formed by the metal and its 4 ligands. This plane can serve as a plane of reflection, and any mirror image of a square planar complex across this plane is clearly superimposable onto itself, so it cannot have chirality just by having 4 different ligands alone.)
2. The metal centre has a chiral ligand (i.e. the ligand itself has a non-superimposable mirror image).
- Following the sub-bullet under Point #1, a square planar complex can be chiral if it has a chiral ligand.