Low oxidation state group 13 element(I) heterocycles and amides: syntheses and reactivity studies

This thesis is mainly concerned with investigations into the synthesis and reactivity of the five membered group 13 element(I) N-heterocyclic carbene (NHC) analogues, [:Ga(DAB*)]-, (DAB* = {N(Ar*)C(H)}2, Ar* = C6H2{C(H)Ph2}2Me-2,6,4) and [:B(DAB)]-, (DAB = {N(Dip)C(H)}2, Dip = C6H3Pri2-2,6). The preparation of series of monomeric group 13 metal(I) amide complexes, e.g. [ML'] (M = Ga, In or Tl; L' = N(Ar*)(SiMe3)), was also investigated. Work carried out in these areas is divided into five chapters. Chapter 1 provides a general introduction to sub-valent group 13 chemistry, with an emphasis on syntheses and coordination chemistry of group 13 metal(I) N-heterocyclic carbene analogues. Chapter 2 summarizes the high yield synthesis of a new, extremely bulky anionic gallium(I) N-heterocyclic carbene analogue, [(DAB*)Ga:]-. The gallium(I) heterocycle has been utilised in the prepa-rations the heteroleptic zinc and cadmium gallyl complexes. Further investigations into the reactivity of [:Ga(DAB)]- towards groups 4 and 14 metal precursors is also discussed, and the first structurally characterized gallium-titanium bonded molecular complex is reported. Chapter 3 summarizes investigations into the reactivity of the anionic boron(I) N-heterocyclic carbene analogue, [:B(DAB)]-, towards d- and p-block element precursors. Reactions with d-block metal(II) halides have given rise to a number of novel boryl d-block metal complexes. The reactions of [:B(DAB)]- with monomeric group 13 metal(I) amides have resulted in the formation of the first examples of monomeric group 13 metal(II) radical species, [{(DAB)B}2M]• (M = Ga, In or Tl), all of which have been crystallographically characterised. Reactions of [:B(DAB)]- with amido-group 14 (II)/(IV) metal halide precursors have resulted in the first example of a two coordinate B-Ge bonded molecular compound. In addition, the first thermally stable acyclic silylene is been reported as part of a collaborative study. Chapter 4 details the preparation of a series of monomeric, one-coordinate group 13 metal(I) amides, e.g. [ML'] (M = Ga, In or Tl). The results of crystallographic studies, in combination with computational analyses, reveal that the metal centers in these compounds are one-coordinate, and do not exhibit any significant intra- or intermolecular interactions, other than their N-M linkages. One of the complexes, [InL'], represents the first example of a one-coordinate indium(I) amide. Chapter 5 describes several miscellaneous results, largely derived from attempts to prepare bulky amidinate complexes of group 13 elements, as well as the use of N-heterocyclic carbenes as ligands to synthesize d- and p-block metal complexes.