History of homogeneous catalysts

We will discuss some of the recent advances in the area of alkene polymerisations catalysed by homogeneous complexes of zirconium and 

Twenty years later Reichert [9] and Breslow [10] discovered that the addition of small amounts of water to the alkylaluminum chloride co-catalysts resulted in a one to two orders of magnitude increase in ethylene polymerization activity. In the 1980s the first reports appeared concerning the homogeneous stereospecilic polymerisation, but they received relatively little attention because in the same period the first highly active, supported, 

The explanation for the existence of a stereo-block polymer is that after a mistake this mistake will propagate as the chain end controls the stereochemistry of the new centre to be formed. Thus after the mistake has occurred, the polymer switches the stereochemistry from s to r. 

Modification of the cyclopentadienyl ligands has led to a very rich chemistry and today a great variety of microstructures and combination thereof can be synthesised as desired including isotactic polymer with melting points above 160 °C, syndiotactic polypropene [16], block polymers, hemi-isotactic polymers etc. 

Another, independent development involves vanadium catalysed propene polymerisation leading to syndiotactic polypropylene [20], see 10.2.1. 

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