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Catalytic synthesis of amines : from small molecules to nitrogen-containing polymers

University of British Columbia

The research presented in this thesis highlights the utility of N,O-chelated complexes of early transition metals for the catalytic synthesis of amines. Two atom economic transformations to make carbon-carbon and carbon-nitrogen bonds, hydroaminoalkylation and hydroamination, were investigated. A significant expansion of the substrate scope of a pre-established catalytic system is presented, and a variety of novel titanium precatalysts were developed and screened for catalytic activity. The products of hydroaminoalkylation were employed as monomers for ring-opening metathesis polymerization using known ruthenium-based catalysts. These amine-containing polymers show interesting rheological behavior attributed to the presence of hydrogen bonding interactions. The substrate scope of a previously reported tantalum phosphoramidate complex capable of room temperature reactivity was expanded to include a solvent-free protocol. This methodology was shown to afford amine products in comparable or greater yields than the related diluted reactions. Titanium metal was investigated as an alternative to tantalum-based precatalysts. A family of mono-, di-, and tri-substituted phosphoramidate complexes was presented, with mono-phosphoramidates outperforming the others in the catalytic synthesis of amines, despite being susceptible to unwanted ligand redistribution reactions. The selective mono-alkylation of cyclic diene substrates was shown to generate strained alkene products suitable for use in ring-opening metathesis polymerization. Despite having unsaturated, Lewis-basic moieties, these monomers were polymerized to generate a variety of viscoelastic homopolymers bearing substituted aryl-amines with tunable hydrogen bonding potential. Thermal and rheological analysis revealed behaviours characteristic of hydrogen bonding, such as increased glass transition temperatures, and viscosity dependent on molecular weight and amine substitution. An expansion of the monomers amenable to polymerization was presented, and a variety of copolymeric structures were synthesized. Efforts focused on pairing amine-containing monomers with those of commodity plastics, such as norbornene. Excellent control over monomer incorporation was achieved in most cases. Preliminary investigations into useful applications of these novel polymers were presented and include anti-microbial materials, agents for sequestering metal ions, and compatibilizers for polymer blends. These preliminary experimental results show promise and future efforts will focus on realizing the full potential of these unique materials.

Text

2018-03-31

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/63137

Chemistry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/