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Postby bgiorgi_3A » Mon Nov 30, 2020 12:57 pm

Hey guys! I keep getting confused on homework problems asking me if a ligand is polydentate. Would someone be able to explain to me what I should look for to determine if something is polydentate or not?

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Re: polydentate

Postby IanWheeler3F » Mon Nov 30, 2020 1:02 pm

Polydentate are usually organic structures with ammine groups, which in english is a big carbon- net with a bunch of nitrogen groups, and the nitrogen groups are the ones that bond to the metal. They are usually abbreviated so if you see en, pn, dien, trien, EDTA then these are all polydentate. Then there is the weird one oxalato, which just has carbon and oxygen and the oxygens are the ones that bond.

Jagveer 1I
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Re: polydentate

Postby Jagveer 1I » Mon Nov 30, 2020 1:19 pm

Just to add on, a polydentate is a ligand that can attatch to more than one binding site simultaneously and the prefix used is bis-, tris-, or tetrakis- to define that polydentate. An example of a polydentate is bidentate ethylenediamine, where each end of the molecule has a nitrogen atom with a lone pair.

Vanshika Bhushan 1A
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Re: polydentate

Postby Vanshika Bhushan 1A » Mon Nov 30, 2020 1:29 pm

A polydentate ligand can be recognized by having more than 2 lewis base sites, including multiple lone pair donating sites used to bond to a central atom or ion.

Samantha Pedersen 2K
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Re: polydentate

Postby Samantha Pedersen 2K » Mon Nov 30, 2020 2:31 pm

In addition to having multiple lone pair donating sites, I believe a polydentate ligand must also have bonds that can rotate (single bonds/sigma bonds) so that the atoms with the lone pairs can orient themselves to be on the same side to bind to the transition metal. I hope this helps!

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