| dc.description.abstract | Transition metal allyl complexes are a class of compounds that are both historically important and currently relevant. The parent allyl ligand (C3H5-) can be modified with sterically bulky R groups (R = trimethylsilyl. tert-butyl) at the terminal allyl carbons; complexes with these modified ligands often show much greater stability than analogous complexes of the parent allyl. An excellent example of this is provided by the bis(allyl) complexes of nickel; bis(C3H5)nickel spontaneously decomposes at 20 ˚C, while bis(1,3-trimethysilylallyl)nickel is indefinitely stable under ambient conditions. The stability provided by these ligands can be leveraged in several useful ways. The stability and ease of quantitative characterization made bis(1,3-trimethysilylallyl)nickel a convenient target for the study of factors directing the course of salt metathesis reactions. This investigation demonstrated a limitation in a commonly used parameter for quantifying solvent in mechanochemical systems, identified the most important role that solvent plays in the synthesis of allylnickel compounds by salt metathesis, and generated a preliminary model for choosing an ideal transition metal source for a given salt metathesis reaction. The synthesis of allylnickel complexes featuring the less common (1,3-di-tert-butylallyl) ligand was studied; this demonstrated the generality of stabilization via 1,3-disubsituted allyls and identified one compound as showing unique resistance to the binding of ancillary ligands. The stability of the (1,3-di-tert-butylallyl)nickel fragment was then used in order to synthesize and characterize several derivative allylnickel complexes. These include previously catalytic intermediates not previously isolated and complexes with uncommon supporting ligands. Finally, the potential utility in catalysis that bulky allyl complexes could display is discussed, and some preliminary steps towards such applications is presented. | |
