Low-Valent Main Group Complexes and their Transition Metal-like Reactivity

Abstract

The work presented in this thesis describes the isolation of novel low-valent Group 12 and p-block element-containing molecules. Some of these molecules are shown to exhibit reactivity which mimics that of the transition metals; specifically, with respect to strong bond activation and catalysis. In order to isolate these reactive main group compounds, several stabilization strategies were employed. Lewis base stabilization using bulky N-heterocyclic carbene (NHC) ligands proved to be highly valuable in the formation of reactive sites involving electropositive elements. Using NHCs, both cadmium and germanium-based molecules are shown to be active ketone reduction catalysts. Additionally, an extremely bulky NHC ligand was synthesized and demonstrated to stabilize low-coordinate inorganic cations of silver, thallium and germanium. Finally, a bulky anionic (vinylic) donor based on an N-heterocyclic carbene framework proved to be highly effective in the stabilization of low-coordinate, reduced main group environments. This includes the synthesis of two-coordinate silicon compounds which, at the present time, are still exceedingly rare owing to their high degree of reactivity. One such species is shown to cleave strong organic and inorganic σ-bonds, thus demonstrating transition metal-like reactivity with the 2nd most abundant element in the Earth’s crust.