Why does [Ni(gly)2] show optical isomerism despite having no chiral carbon?

coordination-compounds stereochemistry chirality

1,380

Your assumption that $\ce{[Ni(gly)2]}$ shows optical isomerism is incorrect: the complex is square planar in nature and has a plane of symmetry (the plane passing through all the atoms). It is thus achiral and does not have any optical isomers.

It does show geometrical isomerism though, as the ligands are not symmetric with reference to each other.

1,380

A Y

Updated on January 31, 2023

Comments

A Y 4 months

For optical isomerism chiral carbon should be present i.e. carbon with four different groups but this compound doesn't have one then why does it show optical isomerism?
- Ivan Neretin over 2 years
  
  For optical isomerism, a molecule should be different from its mirror image; that's all. Whether it contains a chiral carbon (or any carbon at all, for that matter) is irrelevant.
- Zhe over 2 years
  
  @Maurice Glycine is the achiral amino acid since there is no carbon center with 4 different substituents (R = H).
- Zhe over 2 years
  
  @AY The key here is to ask how the glycines are arranged around the central nickel atom. If the arrangement breaks enough symmetry, then the complex is not superimposable on its mirror image.
- permeakra over 2 years
  
  Is it optical isomerism, though? I can see how it could have cis/trans, but not optical.
- Zhe over 2 years
  
  @permeakra There's not enough information to know for sure, but I could imagine a chiral complex if the glycines were bidentate on a tetrahedral complex.
- Jan over 2 years
  
  Dear anonymous editor, please stop submitting edits that attempt to change gly into a sum formula. For one, gly is easier to read and understand. For two, the sum formula you are suggesting is outright wrong. For three, MathJax should not be used in titles anyway (but that only applies to the question).
- Martin - マーチン over 2 years
  
  @Jan (or any one else): Please flag if the vandalism continues. We might have some rather harsh options at our disposal, but we might need to use them if this continues.
- A Y over 2 years
  
  Could you all please explain to me why somebody else has an access to edit my question because continuously somebody is editing it , actually I am very new to this platform , please tell if there is anything that I can do to help.
- Martin - マーチン over 2 years
  
  On this site we aim to have high quality questions and answers. Every user has the ability to edit posts, or suggest such edits. In the latter case they will be reviewed by more experienced users. Editing can have multiple reasons, some are introducing better formatting, correcting spelling, adding tags, giving a better title, etc.. Please take the tour to find out more about this site and if you have more questions related to that, visit Chemistry Meta. Unfortunately, you question has been targeted by an anonymous editor for a while. I hope that is over now.