The objective of this project is synthesizing bipyridine-derived ligands in order to study DNA conformational bending. The synthesis of bipyridine derivatives has been investigated. 6,6’-Dibromo-2,2’- bipyridine and small scale of 6,6’-diformyl-2,2’-bipyridine have been successfully synthesized in the laboratory. The synthesis of large amount of a direct precursor to 6,6’-diformyl-2,2’- bipyridine in an multiple step way has been achieved. The synthesis of mono functionalized pyrene derivatives and of 1,6-dissymmetrically functionalized pyrene derivatives has been heavily studied. Successfully methods have been reported in this thesis. The complete assembly of bipyridine and pyrene units into the final ligands and their model has also been studied. Palladium borylation and Suzuki-Miyaura cross-coupling have been used to successfully connect the bipyridine with pyrene units. In addition to Suzuki-Miyaura methodology, the direct coupling of N,N’-dioxide-2,2’- bipyridine with aromatic bromides under palladium catalysis has been investigated. This method could be an alternative way to access to mono-substituted 6-bipyridines, symmetrically or even asymmetrically 6,6’-disubstituted-2,2’-bipyridine derivatives. / Thesis (Master, Chemistry) -- Queen's University, 2009-09-06 01:06:41.646

This thesis describes the synthesis and characterisation of metal complexes that contain chemically reduced bipyridyl ligands. The crystal structures of twenty-six novel complexes are reported alongside detailed discussions on the electronic and spectroscopic effects and trends associated with the different oxidation states within these species. Chapter One introduces the isomers of bipyridine and their redox chemistry, the concept of non-innocent ligands and the spectroscopic techniques that are currently used in determining ligand oxidation states. Subsequently, examples of main group, transition metal, lanthanide and actinide species that contain or may contain reduced forms of the ligand are discussed. Chapter Two details the synthesis and structural characterisation of alkali metal salts of singly and doubly reduced forms of the three commercially available bipyridine isomers. The effects of this reduction are investigated with the aim of developing diagnostic fingerprints for each of the ligand oxidation states. Chapter Three discusses the synthesis of an homologous series of compounds of the form [M(2,2'-bipy)(mes)₂]^n– where M = Cr, Mn, Fe, Co, Ni and n = 0, 1. Trends in magnetism, bonding and electronic structure are investigated with reference to theoretical calculations and the diagnostic fingerprints identified in the previous chapter. Chapter Four describes the synthesis and characterisation of three compounds containing the isostructural motif [Zn₂(4,4'-bipy)(mes)₄]^n– where n = 0, 1, 2. Structural and spectroscopic changes are discussed and com- pared to theoretical calculations. Chapter Five contains descriptions of the spectroscopic techniques employed in the above research and synthesis routes to all compounds featured in this thesis.