Polydentate ligands

[Jacquelyn Challis 2B]

Question 9C.5 says: 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(CH2 CH2 NH2)2 ; (b) CO3 2 − ; (c) H2O; (d) oxalate. I'm not really sure what a polydentate ligand is and also how can you tell whether a compound is or not?

[705383815]

I think polydentate ligands are compounds that can offer multiple atoms within themselves to bond with a metal atom or cation. They have many atoms that have electron pairs or distributions that can bond to the central atom.

[Joyce Pang 2H]

A ligand is a molecule that bonds to a central atom, and a polydentate ligand would be one that has multiple sites where bonding can occur through lone pairs. You would have to draw out the lewis structure for each compound and see which sites with lone pairs can bind to atoms.

[Algernon Jackson 2l]

I believe polydentate ligand is a ligand that has greater than two binding sites.

[Khoa Vu 3l]

As others have said before me, a polydentate ligand is a molecule that can bond to the same central atom multiple times through different bonding sites and offer multiple lone pairs through different atoms within the same molecule. You can typically tell whether not an atom is polydentate based on the available lone pairs there are to donate on each atom. Only one lone pair can be donated per atom, though, due to the atom being locked in a certain orientation once the lone pair is donated. In order to donate multiple lone pairs then, the molecule must have spacer atoms between the atoms donating the lone pairs. For example, en, C2H4(NH2)2, is bidentate because of the two lone pairs between two nitrogens. The spacers are the single-bonded (sigma bonds) Carbons which can then rotate the orientation of the molecule once one nitrogen's lone pair has been donated so that the other nitrogen can donate a different lone pair to the same central atom. The spacers must be single bonded due to the cylindrical symmetry within sigma bonds, if it is doubled bonded, the pi bond prevents rotation.

[derickngo3d]

Polydentate ligands can use several atoms to bond to a central transition metal atom.

[205323697]

How would we know the position of all the ligands?