Structural and catalytic studies on novel copper complexes
[Thesis]
Zelenay, Benjamin Sylvester
Díez- González, Silvia
Imperial College London
2017
Ph.D.
Imperial College London
2017
Transition metal complexes and their chemistry are providing synthetic chemists and the chemical industry with simpler and less tedious synthetic procedures but also opened endless doors to new synthetic transformations that had been thought impossible. The main advantage of transition metal chemistry is that these complexes are often used in substoichiometric amounts to perform the desired reaction. Other benefits such as high atom efficiency or fewer amount of by-products are often observed as well. Despite all these advantages, the commonly utilised transition metals are either expensive, toxic, and/or prospected from politically unstable regions. Copper, a less toxic and economical transition metal, circumvents these downsides. The first Chapter outlines a brief overview of Schiff bases and their utilisation in transition metal chemistry including a discussion on diazabutadiene (DAB) and iminopyridine (ImPy) ligands, their complexes, and their reported applications. Furthermore, it includes the accounts for the preparation of DAB and ImPy ligands and their novel copper(I) complexes. The characterisation and X-ray structures of these complexes and in depth studies into the solution behaviour of [Cu(DAB)] complexes are discussed as well. The second Chapter outlines an introduction to the chemistry of amines. It gives a brief overview over their importance in chemistry and their preparation, and a focus on the synthesis of primary amines from azide precursors. Furthermore, the utilisation of amines in the hydroamination reaction is reviewed and the application of copper(I) complexes in the literature is examined. In Chapter 3, results of our successful attempts to exploit [Cu(DAB)] in the reduction of aryl azides are presented. In addition, computational studies are included to introduce the proposed reaction mechanism. The fourth Chapter includes our efforts to apply the prepared copper(I) complexes in the intra- and intermolecular hydroamination reaction of primary and secondary amines to a variety of carbon-carbon unsaturated bonds. The preparation for the various starting materials and the isolation of their corresponding products is discussed. The fifth Chapter provides a summary and the general conclusions of our studies and the final Chapter contains all experimental procedures and characterisation data for all compounds synthesised during this project.