3d Transition Metal Complexes of N-Heterocyclic Carbene Ligands and N-Heterocyclic Ligands

  • Kieran Weldon

Student thesis: Master of Philosophy


Abstract The synthesis of two new [Fe{N(SiMe3)2}{μ-N(SiMe3)2}]2 complexes; [(Fe{N(SiMe3)2}2)2(bipyrimidine)] (2.1) and [Fe{N(SiMe3)2}2(phenanthroline)] (2.2) are discussed. These complexes have been analysed by NMR spectroscopy and the additional solid-state structures have been obtained using X-ray crystallography. The corresponding [Co{N(SiMe3)2}{μ-N(SiMe3)2}]2 complexes; [(Co{N(SiMe3)2}2)2(bipyrimidine)] (2.4) and [Co{N(SiMe3)2}2(phenanthroline)] (2.5), have been synthesised and isolated. These are discussed and have been analysed by NMR spectroscopy, the additional solid-state structures for both these compounds were obtained using X-ray crystallography. Complex 2.1 was reacted with a number of alcohols and imidazolium chlorides. Complex 2.2 was reacted with selected imidazole chlorides. Both sets of reactions for complexes 2.1 and 2.2 are discussed. No further reactions were carried out with complexes 2.4 and 2.5. [(Fe{N(SiMe3)2}2)3(hexaazatrinapthalene)] (2.3), was synthesised and further reactions with numerous imidazole chlorides were carried out and these are discussed. Successful reaction of [(Fe{N(SiMe3)2}2)3(hexaazatrinapthalene)] and ItBu.HCl, resulted in the formation of a new complex (2.15), the structure of which has been obtained through X-ray crystallography. The reaction needs to be repeated in order to obtain full characterisation. A tetrapodal ligand (2.21) was synthesised according to an established literature procedure. This ligand was reacted with [Fe{N(SiMe3)2}{μ-N(SiMe3)2}]2 and manganocene in THF, the reactions produced insoluble solids. NMR spectroscopy has been attempted on both products. A reaction with [Fe{N(SiMe3)2}{μ-N(SiMe3)2}]2 in bromobenzene was also carried out, producing an insoluble solid, NMR spectroscopy was attempted using benzene-d6 but this has so far been unsuccessful. The synthesis of a new P(V) bridged NHC, [O=P{NHC(H)}3]3+ [OS(=O)2CF3]-3 complex (2.29), is discussed. This new tripodal NHC has been characterised using NMR spectroscopy and elemental analysis. Characterisation via X-ray crystallography was not possible, as explained in the results and discussion chapter. [O=P{NHC(H)}3]3+ [OS(=O)2CF3]-3 was reacted with manganocene to produce a new octahedral manganese complex (2.30), which is discussed. The complex has been characterised by NMR spectroscopy and elemental analysis. Additionally a solid-state structure has been obtained through X-ray crystallography.
Date of Award1 Aug 2015
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorRichard Layfield (Supervisor) & Alan Brisdon (Supervisor)

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