Synthesis and reactivity studies of low valent germanium compounds

Thesis

This thesis describes the synthesis, characterisation and reactivity studies of NHC-amido and phosphine-amido stabilised low valent heavier group 14 compounds.

In Chapter 1, a general introduction of the development of interesting main group compounds in the recent decades is provided. The classes of compound include carbenes, metallylenes, low valent germanium cations and the heavier group 14 alkyne analogues. The reactivity patterns of these types of compound are also discussed. The aims of this DPhil project are described.

In Chapter 2, the experimental techniques and analytical methods employed in this project are summarised. Details of starting materials syntheses following modified literature procedures are also given.

In Chapter 3, the synthesis and structural properties of a series of low valent monohalo germanium, tin and lead compounds stabilised by a chelating N_amido^C_NHC ligand system are described and compared. These compounds serve as precursors towards more reactive derivatives in the following chapters. The synthesis of a Ge(I) dimer upon reduction and its preliminary reactivity towards dihydrogen are also explored.

In Chapter 4, the synthesis of two novel germyliumylidene cations featuring a N_amido^C_NHC ligand system and their activation of O-H and N-H bonds via metal ligand cooperation, as well as the oxidative addition of C-Cl bond in dichloromethane, are detailed.

In Chapter 5, the synthesis of low valent germanium(II) compounds stabilised by a N_{amidophosphino} ligand is investigated. From a common chlorogermylene precursor, a novel germyliumylidene and other Cl-substituted Ge(II) derivatives can be achieved. Attempts to synthesise a Ge(II) hydride in situ are described and the isolated Ge(II) naphthoxide is shown to act as an effective pre-catalyst in hydroboration reactions.

Authors: Zhou, X

• DOI: 10.5287/ora-gp09vyjpo
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford