Electronic structure and mechanistic studies of non-traditional Ziegler-Natta catalysts

This thesis focuses on the structure and reactivity of a variety of inorganic systems through the exploration of their electronic structure by employing density functional theoretical methods. Chapter 1, the introduction, outlines the theoretical approaches and includes a historical overview of the development of quantum theory. The theoretical methods and their applications are then described and discussed. The first chapter concludes with an overview of the work undertaken. Chapter 2 presents a historical background of the experimental and theoretical work done on traditional Group IV Ziegler-Natta catalysis inculding the generally accepted mechanisms believed to be employed when these systems are used to polymerise olifins. Furthermore, a description of the experimental results obtained when a non-traditional Ziegler-Natta catalyst was subjected to proplyene are given as a rationale for the calculations presented in Chapter 3. Chapter 3 presents a theoretical exploration of a novel class of olefin polymerization catalysts based on the tris(amido)titanium(IV) platform. Here, DFT has been used to probe the electronic structure of these compounds in order to provide a rationale for the catalytic activity that is associated with them as well as a possible new mechanism for this type of non-traditional catalyst. Furthermore, Chapter 4 takes a closer look at a large number of potential intermediates that are available for the polymerization reaction discussed in Chapter 3. In Chapter 5, a series of simple transition metal complexes are calculated and analysed to further understand key aspects of the system. The complexes represent a basic model of the novel catalysts found in Chapter 3 and contain the essential feature of p-acid-base chemistry within the coordination sphere.