CHAPTER 1 briefly discusses the stereochemical effect of replacing oxygen with sulphur as donor atoms, with particular reference to the p- diketonate complexes and their thio -analogues. CHAPTER 2 describes the synthetic procedures applied to extend the range of planar dithio -ß- diketonate complexes of palladium and platinum, their subsequent characterisation by a number of spectroscopic techniques and comparison with the analogous nickel complexe. CHAPTER 3 discusses the electrochemical behaviour of the Ni, Pd and Pt dithio -ß- diketonates. The complexes undergo two successive one -electron reductions, with a marked tendency for the monoanion to undergo a rearrangement reaction. Reduction potentials are strongly influenced by the inductive nature of ligand substituent groups, and comparison with related systems suggests the redox -active orbital of the 1,3- dithio complexes is of largely ligand character. Our study was extended to include a number of isostructural palladium ß- diketonate complexes and preliminary work concerning nickel monothio -ß- diketonates. CHAPTER 4 presents a detailed kinetic study of the rearrangement of the one -electron reduced species by cyclic voltammetry, showing it to be a dimerisation reaction. Measurements over a temperature range yield activation parameters which are also in line with a bimolecular reaction. CHAPTER 5 describes the synthesis and electrochemical characterisation of a number of cobalt(II) dithio -ßdiketonates. A concentration study of [Co(SacSac)2] shows anomalous behaviour when using mercury as a working electrode. Reversible reaction with dioxygen is also discussed briefly.