Aryl-NHC group 13 trimethyl complexes : structural, stability and bonding insights

Abstract

This first aim of this thesis was to synthesize a series of new N-heterocyclic carbene group 13 metal complexes. The synthesis of the new compounds was achieved using group 13 trimethyl complexes and NHC starting materials. The species produced comprises of aluminium, gallium and indium group 13 metals. Furthermore, reactivity studies have also been carried out on the obtained NHC species with a series of electrophiles. All the structures synthesized have been fully characterized by single crystal X-ray studies, multi-nuclear NMR, IR and mass spectrometry.

The second aim of this thesis was to investigate the origin of the range of stability displayed by the newly synthesised complexes. These differences have been assessed using percent buried volume, %VBur, topographic steric maps, dissociation energy, Ediss, and calculated bond snapping energy (BSE) decomposition analysis of the M-NHC bonds (M = Al, Ga and In). The results obtained indicated that the differences in stability observed are mainly attributed to small differences in the steric demands of the NHC ligands.

Finally, preliminary investigations to evaluate applicability and efficiency of solvent-free mechanochemical techniques for the synthesis of main group NHC complexes have been carried out. The rapid and high yielding syntheses of NHC gallium and indium trichlorido complexes highlight the potential of this technique.