2. Catalysis by coordination complexes

2.1 Elementary stages and catalytic cycle

A catalyst is a chemical substance which facilitates a reaction by taking part in it, but which is found unchanged at the end of the reaction.

In addition to observing the catalytic reaction, which in itself, through the nature of the products formed, already provides information on the catalyst's mode of action, the synthesis of assumed reaction models and the study of their reactivity enable us to describe the actual reaction step by step.

A catalytic reaction can thus be broken down into a number of elementary steps, for example:

• activation by simultaneous or successive coordination of substrate and reagent ;

• reaction...