Organometallic chemists have long studied and conceptualized the bonding of metals with ligands to explain and predict structure, reactivity and inform synthesis of species of interest. Gold, a metal which has attracted much attention from society, has in the past two decades been the subject of intensive research into its organometallic chemistry and catalytic applications. This work explores the impact of gold(I) bonding on novel gold(I) complexes, invoking new conceptual perspectives to describe and rationalize observed behaviors.
Chapter 1. A brief introduction to some relevant characteristics of gold is provided. In particular, bonding characteristics of gold in the oxidation state +1 is discussed.
Chapter 2. The synthesis of the first gold(I)-cyclobutadiene is described. Its unusual coordination motif is observed and rationalized by the use of energy decomposition analysis (EDA). EDA reveals the importance of Pauli repulsion in both cyclobutadiene but also alkyne complexes of gold(I). Consequently, the bonding model of gold(I) was modified by including the hitherto overlooked concept of Pauli repulsion between the gold(I) center and the π-ligand.
Chapter 3. Difluorocarbene insertion into gold(I)-carbon bond of alkyl- and aryl-gold(I) complexes to form novel nucleophilic R-CF2-Au(I) complexes is described. The motivating hypothesis invoked a new perspective: leveraging the linear bonding preference of gold(I), often a limitation in terms of the coordination chmistry of gold(I), to stabilize the novel products against α-fluoride elimination. The two key processes of α-fluoride elimination and difluorocarbene insertion, at the intersection of organometallic and fluorine chemistry, were investigated by density functional theory calculations.
Chapter 4. The [1+2] cycloaddition of an alkynyl-gold(I) complex with difluorocarbene is described, forming an unprecedented transition metal species bearing a gem-difluorocyclopropenyl ligand. The reactivity of the alkynyl-gold(I) complex is explored and rationalized by density functional theory calculations.
