Overview of Ligand Substitution

Many examples of associative and dissociative mechanisms are presented in later sections. One classic example of ligand substitution that exhibits the hallmarks of an associative substitution process is the replacement of chloride in a 16-electron complex, such as Pt(PEt3)2Cl2. One classic example of a ligand substitution that exhibits the hallmarks of a dissociative mechanism is the substitution of phosphine for carbonyl in Ni(CO).  

Ip if this is the transition state of the rate-determining step 

The Basic Factors that Control Ligand Substitution Mechanisms 

Type of complex Occurs with 16-e and 17-e complexes Occurs with 18-e complexes 

Rate law First order in entering ligand Typically zero order in entering ligand 

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