Polydentate Ligands

[Brianne Conway 1D]

To determine if a ligand is polydentate and to specifically find how many places it can bind, do you have to draw the Lewis structure or is there some other intuitive way of knowing how many lone pairs it has? Asking because textbook exercise 9C.5 lists ligands and asks to identify which can be polydentate, and in the answer it doesn't show the Lewis structures or anything, just explains how it can bind through different atoms.

[Claire_Latendresse_1E]

For those textbook problems, I drew out the Lewis structures and looked for atoms that had lone pairs. For example, for water, the oxygen has lone pairs, so it can be a monodentate ligand (it's not a bidentate ligand because the two lone pairs are on the same bonding site).

At the UA session earlier today, Michael said that it would be very helpful for the final to memorize some of the most important polydentates: en, dien, EDTA, oxalate, and porphyrin.

[Pranav Kadiyala 1A]

Additionally, some other guidelines are if there is typically 2 "spacers" between the bonding sites, and if they are connected by sigma bonds, so they can "get around"/rotate to bond.


Hope this helps :)

[Brianne Conway 1D]

For those textbook problems, I drew out the Lewis structures and looked for atoms that had lone pairs. For example, for water, the oxygen has lone pairs, so it can be a monodentate ligand (it's not a bidentate ligand because the two lone pairs are on the same bonding site).

At the UA session earlier today, Michael said that it would be very helpful for the final to memorize some of the most important polydentates: en, dien, EDTA, oxalate, and porphyrin.

Great, thanks a lot!

[Karina Grover 1A]

I remember a problem similar to that! It is helpful just to remember them off the top of your head. "en" is bidentate, "dien" is tridentate, and "edta" is hexadentate. Hopefully this is helpful!

[Nancy Yao]

For those textbook problems, I drew out the Lewis structures and looked for atoms that had lone pairs. For example, for water, the oxygen has lone pairs, so it can be a monodentate ligand (it's not a bidentate ligand because the two lone pairs are on the same bonding site).

At the UA session earlier today, Michael said that it would be very helpful for the final to memorize some of the most important polydentates: en, dien, EDTA, oxalate, and porphyrin.

That is very useful information! Thanks a lot.