Novel chemistry of the teflate group.

This thesis is concerned with the preparation and characterisation of low-valent teflate (-OTeF5) compounds. Reported here are a range of novel low-oxidation state transition-metal complexes. An indepth introduction to the general area of teflate chemistry is given in Chapter 1, including a description of the previous work performed in the field of low-valent teflates. Chapter 2 describes the preparation and spectroscopic characterisation of HOTeF5 and AgOTeF5, the teflate transfer reagents commonly used throughout this Ph.D. The experimental procedures for the reactions described elsewhere are given in the experimental chapter i.e. Chapter 7. In Chapter 3, evidence for a square-planar platinum (II) bis-triethylphosphine teflate complex is described. This is in direct contrast to a previous report which stated that "teflate and phosphine (III) ligands are mutually incompatible". In Chapter 4, this work is extended to triphenylphosphine complexes, proving that this ligand can also form stable teflate complexes. This chapter details the preparation of the first alkyl carbonyl teflate species, and the first low-valent osmium teflate complex. Chapter 5 describes the reactions between Fe, Ru and Os carbonyl phosphine complexes and HOTeF5. These reactions result in protonation of the metal centre, forming the respective cations, The teflate is strongly associated as the counterion for these species. Preliminary evidence for the first ruthenium teflate complexes is given in Chapter 6. Chapter 7 details the procedure for the reactions described in Chapters 3-6. Multinuclear NMR spectroscopy was utilised for analysis of the products, 19F NMR spectroscopy is diagnostic for teflate compounds, and is useful for determining the ionicity of the complex. Other nuclei, such as 31P and 13C, can be used to identify the products in solution, and also the stereochemistry at the metal centre.