The Use of Spectroscopy in Metallocene-based Polymerisation Catalysis

Group 4 metallocene complexes were reported by Wilkinson in early 1953 [4], a few months before Ziegler s seminal discovery that mixtures of TiCl4 and AlEt3 catalysed the polymerisation of ethene. It was not long before the new compounds were tested as potential ethene polymerisation catalysts, not least because these 

Mechanisms in Homogeneous Catalysis. A Spectroscopic Approach. Edited by Brian Heaton Copyright 2005 WILEY-VCH Veriag GmbH Co. KGaA, Weinheim ISBN 3-527-31025-8 

The need for Lewis acidic main group alkyls as activators, which can form complexes with the inactive catalyst precursor and are capable of transferring an alkyl ligand [7]  

oxidation state IV for the active species and reduction as a deactivating side reaction [7, 8]  

polymer chain growth by monomer insertion into a Ti-alkyl bond [8]  

---

I 8 The Use of Spectroscopy in Metallocene-based Polymerisation Catalysis Chain-end control ... 

Over the last 20 years, there has been an enormous increase in the use of NMR spectroscopy in metallocene-based polymerisation catalysis and these studies have provided an unprecedented increase in our understanding this has allowed the properties of homo- and co-polymers to be tailored and transition state energies to be lowered by 1-2 kcal mol , which makes all the difference between a poor and a highly successful catalyst. 

---