Isomerism in d-block metal complexes

  In this book so far, we have not mentioned isomerism very often, and most references have been to trans- and cis-isomers, e.g. trans-[CaI₂)THF(₄] and the trans- and cis-isomers of N₂F₂. These are geometrical isomers, and our previous discussion of this topic will not be elaborated further here.

Self-study exercises

1. Draw possible structures for the square planar complexes [PtBr₂(py)₂] and [PtCl₃(PEt₃)]^-and give names to distinguish between any isomers that you have drawn.

2. In [Ru(CO)₄(PPh₃)], the Ru centre is in a trigonal bipyramidal environment. Draw the structures of possible isomers and give names to distinguish between them.

3. Draw the structures and name the isomers of octahedral [CrCl₂(NH₃)₄]‏⁺.

4. Octahedral [RhCl₃(H₂O)₃] has two isomers. Draw their structures and give them distinguishing names.

   In this section, we shall be concerned with other types of isomerism exhibited by d-block metal complexes, and we use a classification that goes back to the work of Werner (Figure 1.1).

Fig. 1.1 Classification of types of isomerism in metal complexes.