The characteristic reactions of organometallic complexes are described in Chapter 6. By combining these elementary reactions, transformations catalyzed by organometallic complexes can be constructed. In order for the catalyst to work effectively, certain system conditions need to be considered. Careful selection of the following are particularly important:

It is not easy to determine the optimal conditions, but many excellent catalytic systems have been discovered and industrialized. This chapter introduces representative reaction systems catalyzed by organometallic complexes, and outlines the reactions occurring.

The olefin polymerization catalysis created by Ziegler is very useful because the reactions occur at room temperature and under normal pressure. Although Ziegler catalysts are prepared from tetrachlorotitanium (TiCl₄) and alkylaluminium reagents (AlEt₃ or AlEt₂Cl), the exact nature of the active species has not been completely elucidated. It is clear, however, that the alkylaluminium ethylates Ti to form a complex with a Ti–Et bond, which plays an important role in the olefin polymerization. The currently accepted catalytic mechanism is shown below.