Polydentate Ligands

[105719095]

How do you determine if a ligand can be polydentate? If it polydentate, how do you find the maximum number of places on the ligand that can bind simultaneously to a single metal center?
For example in textbook problem 9C.5 Which of the following ligands can be polydentate? If the ligand can be polydentate, give the maximum number of places on the ligand that can bind simultaneously to a single metal center:

(a) HN(CH2CH2NH2)2

[Coline Luo 2E]

You can determine if a ligand is polydentate by drawing the Lewis structure and seeing if there are multiple lone pairs on the atoms, in addition to making sure that the molecular geometry allows for the binding of these lone pairs. This generally requires there to be spacers in the ligand, which allows for the flexibility for the electron regions to interact with the transition metal. After determining these factors, you just total up the number of possible bonding lone pairs to find the denticity. For example, in problem 9C5.a, after drawing out the Lewis structure, you can see that there are 3 nitrogens with lone pairs. Since there are only single bonds, they can rotate to allow all the lone pairs to interact with the transition metal. Thus, this compound is tridentate. Hope this helps!

[LukeYing_3H]

You can determine if a ligand is polydentate by drawing the Lewis structure and seeing if there are multiple lone pairs on the atom and molecular geometry that would allow these lone pairs proper room to bind.

[Aida Fraser 2I]

So all you need to figure out is how many lone pairs there are and then you know the denticity? Is there a table / chart for the denticity of ligands

[Aida Fraser 2I]

why is water monodentate?

[Charlie Gravereaux]

If you draw out the lewis structure of the compound, you can determine the denticity based on the number of lone pairs present in the atom, and also remember to check if the molecular geometry allows for multiple binding sites. As for water being monodentate, both of its lone pairs are on the oxygen, so there can only be one bond formed between water and the central atom.

[Gavin Trent 2F]

Basically just draw or imagine the lewis structure, and if there are multiple lone pairs on different atoms that have two or more atoms between them, it can by polydentate.