[hoangthanhbinh8]

Hey guys,

I got the question about this complex
[Co(en)₂(H₂O)]³⁺

en: diaminoethane (NH₂CH₂CH₂NH₂)

I tried to draw it but I can't.

They said it can exist as enantiomer, rotate the polar light.

There is another isomer that could not do that.

I can't draw 2 of them.

Can I please get some help?

Cheers.

[mjc123]

Assuming you mean [Co(en)₂(H₂O)₂]³⁺ as in the post title:
Consider the waters first. How many ways are there to arrange two substituents relative to each other in an octahedral structure?
For each of these, how can the two ens be distributed between the four remaining positions? Does this give rise to any isomerism?

[hoangthanhbinh8]

I think it is similar to this one.

The problem is that I don't know how to go from there.

The (en)₂ creates a plane.

I think the 2 water molecules can be in the same side or they can be in the different side comparing to the plane.

I am still thinking about the isomers.

I can't think how it is worked.

[Dan]

I think you need to draw out what you are doing to clarify what the problem is.
The en ligands do not have to be coplanar, there are other possibilities.

mjc123's suggestion is a good one, you should try it. Start with the waters, then add the en ligands.

[hoangthanhbinh8]

Thank you.

I think I got it now.

Wooo hoooooo