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Abstract
This work presents synthetic investigations into main group organometallic chemistry, placing particular emphasis on the study of bis N-heterocyclic carbene (NHC) carbazolide coordination environments. Complexes of high and low oxidation state metals from the s- and p-blocks were targeted and these comprise the content of the experimental chapters two through five.
Chapter one serves as a general introduction to rationalise the intent of this work. Herein, focus is drawn to the nascent field of organometallic main group chemistry in the form of a discussion of its history using pertinent recent examples from the literature.
Chapter two details the synthesis of an emerging class of versatile bis(NHC)carbazolide pincer ligands; bimcaR, and their complexation to s-block metals. The development of a new zwitterionic bis(imidazolium)carbazolide proligand is discussed, as well as the structural metrics of new lithium and magnesium bimcaR derivatives. Specifically, a new iodomagnesium complex is probed for its synthetic utility as a ligand transfer agent and catalytic precursor in conjunction with attempts to access a reduced Mg(I) derivative.
Chapter three focuses on the stabilising effect of the flanking bis(NHC) moieties of bimcaR on high valent group 13 metals and thusly presents a series of exceptionally stable bimcaR supported diiodides from aluminium to thallium. The indium and thallium diiodides are subjected to iodide-hydride exchange reactions to assess the stability of the resulting dihydrides, whilst efforts are also made to access low valent heavy group 13 congeners.
Chapter four concentrates on the extension of this methodology to accessing heavy low valent group 14 complexes with the aim of creating highly activated metal centres to harness main group redox chemistry. To this end, a number of attempts are made to access low valent tin and lead halides with a view toward accessing the corresponding, highly reactive metallohydrides.
Chapter five presents an alternative approach to accessing such reactive group 14 species with the bulky triazenide ligand class, and thereby details the synthesis and steric characterisation of a new superbulky, unsymmetrical N-2,6-terphenyl triazenide ligand.