Question

The anticancer agent, cisplatin is synthesised from K2[PtCl4]. Draw the synthetic route and explain the role of the trans-effect in this synthesis.

Please do not just tell me that one has a greater trans effect than the other. I would like a thorough explanation as to why the CIS conformation arises and how the trans effect explains this, including sigma donor and pi acceptor properties of ligands.

Answer 1

1. In the first step of cis-platin formation, chlorine group is substituted by ammonia randomly but in second step, the ammonia group substitutes the chlorine group to the cis to the first ammonia. This is because, Cl​​​​​- has greater trans effect than NH​​​3

2. Trans product is obtained from Pt(NH​​​​​3)4 2+ . In this case the second Cl group is substituted at trans-position to the first one.