Qualifications for Polydentate

[Pranav Kadiyala 1A]

A polydentate ligand can bind to the central atom at multiple sites simultaneously. This means that there needs to be more than one lone pair site, but how do we decide if the structure can "get around"/rotate to bond at the same time?

[OwenSumter_2F]

If it's polydentate, then it'll be able to bind to those sites, we won't be getting that deep into the actual reality of it in this class.

[Hasmik Dis 2F]

I remember from Dr. Lavelle's lectures that pi bonds do not let bound atoms to rotate. This is also why proteins can change shape/form- because of their single bonds.

[Yuelai Feng 3E]

Hi! Like what the previous answer says, sigma bonds can rotate while the existence of pi bonds restrict rotation. So a ligand (with several lone pair sites) that consists of all single bonds can probably "get around" and form multiple bonds at the same time. Also, there should be enough space between two lone pair sites, so that the TM cation to fit in. Dr. Lavelle mentioned that usually there need to be at least 2 "spacer atoms" between the 2 atoms with lone pair. Hope it helps!