Chemical Forums

Chemistry Forums for Students => High School Chemistry Forum => Topic started by: mystreet123 on June 03, 2016, 01:09:36 PM

Title: How to draw the trans isomer of complexes with two bidentate ligands?
Post by: mystreet123 on June 03, 2016, 01:09:36 PM
I want to draw the trans isomer of oxaliplatin(II) complex but I just couldn't do it. Is it impossible for it to have a trans isomer?

Below is the 2D and 3D images of oxaliplatin(II) complex I found online.
Title: Re: Cis trans square planar isomers
Post by: mikasaur on June 03, 2016, 01:36:19 PM
Hello mystreet123.

Before we can help you must show your own attempts at answering the question. It's part of our rules you can read about here (http://www.chemicalforums.com/index.php?topic=65859.0).

What do you know about cis and trans isomerism? What about a molecule makes it cis or trans?
Title: Re: Cis trans square planar isomers
Post by: mystreet123 on June 03, 2016, 02:04:44 PM
Hello mystreet123.

Before we can help you must show your own attempts at answering the question. It's part of our rules you can read about here (http://www.chemicalforums.com/index.php?topic=65859.0).

What do you know about cis and trans isomerism? What about a molecule makes it cis or trans?

Now I understand that it is a cis isomer but I just couldn't draw a trans isomer. Is it impossible to have a trans isomer?
Title: Re: How to draw the trans isomer of complexes with two bidentate ligands?
Post by: mikasaur on June 04, 2016, 11:30:18 AM
I think I misread your original question. Or you edited it after I read it.

I don't believe it's possible. Both ligands are perfectly symmetrical. You could flip them around and move them around but the molecule would still look the same.

That said I could be wrong, and someone more knowledgeable than me could say otherwise.
Title: Re: How to draw the trans isomer of complexes with two bidentate ligands?
Post by: Arkcon on June 04, 2016, 03:34:16 PM
mystreet123: please reprint your structural formula for this molecule, and draw a red circle around the chiral center.   I don't see one, and the definition of cis and trans requires one.  And no, it isn't possible to only have cis.
Title: Re: How to draw the trans isomer of complexes with two bidentate ligands?
Post by: sjb on June 04, 2016, 04:19:51 PM
It's more to do with strain. If the oxalate was larger, say e.g. succinate and two ammonias as ligands then it may be able to chelate around forming both cis and trans isomers. Don't forget this is not tetrahedral, but square planar.