This thesis investigates the stabilization of divalent germanium using substituted diethanol amine ligands. Germylenes of type RN(CH2CH2OH)2Ge were obtained from N-heterocyclic germylenes and N-alkyl diethanol amines in yields of up to 94%. Single crystal X-ray diffraction confims the presence of a transannular Ge-N dative bond in all cases. In addition, intermolecular dimers containing Ge2O2 rings are formed for R = Me and Et. Reaction of the four germylenes L with nickel carbonyl yielded the respective germylene complexes L2Ni(CO)2 and LNi(CO)3. The germylenes and their complexes were investigated with DFT methods. Only four methods, SVWN, BB1K, MPWB1K and M062x gave acceptable Ge-N distances. Dimerization energies of the germylenes were examined with the thermochemically accurate M062x method. At the M062x/Def2-TZVP level, the dimerization energies of the germylenes are very small (ΔG° ≈ 0 kcal/mol). The experimentally observed dimerization or lack thereof may accordingly be determined by packing effects in the solid state or solvation energies in solution.

Biocatalysts are increasingly prevalent in the large-scale synthesis of enantiomerically pure compounds. However, many sought-after reactions lack a suitable enzymatic production route. This work describes the development of a novel amine dehydrogenase through the application of directed evolution altering the substrate specificity of an existing leucine dehydrogenase scaffold. Eleven rounds of directed evolution completely altered the enzyme’s specificity and successfully created amination activity. The resulting amine dehydrogenase asymmetrically catalyzes methyl isobutyl ketone and free ammonia to 1, 3-dimethyl butyl amine. The enantioselectivity of the wild-type enzyme was maintained despite the drastic changes to the binding pocket and yielded (R)-1,3-DMBA with nearly complete conversion making it an attractive catalyst in the synthesis of chiral amines. This was the first example of a cofactor-dependent amine dehydrogenase capable of selectively synthesizing chiral amines from a prochiral ketone and free ammonia. Additionally, knowledge gained altering the specificity of the leucine dehydrogenase scaffold was applied to an analogous phenylalanine dehydrogenase scaffold allowing for rapid evolution of novel activity. A single mutational library resulted in a second amine dehydrogenase with enhanced activity toward significantly different substrates, while maintaining comparable conversion and enantioselectivity. These two scaffolds provide examples of the broad applicability of the identified mutations in creating amine dehydrogenase activity.

Inhibiting the formation of ice is an essential process commercially, industrially, and medically. Compounds that work to stop the formation of ice have historically possessed drawbacks such as toxicity or prohibitively high active concentrations. One class of molecules, ice recrystallization inhibitors, work to reduce the damage caused by the combination of small ice crystals into larger ones. Recent advances made by the Ben lab have identified small molecule carbohydrate analogues that are highly active in the field of ice recrystallization and have potential in the cryopreservation of living tissue. A similar class of molecules, kinetic hydrate inhibitors, work to prevent the formation of another type of ice – gas hydrate. Gas hydrates are formed by the encapsulation of a molecule of a hydrocarbon inside a growing ice crystal. These compounds become problematic in high pressure and low temperature areas where methane is present - such as an oil pipeline. A recent study has highlighted the effects of antifreeze glycoprotein, a biological ice recrystallization inhibitor, in the inhibition of methane clathrates. Connecting these two fields through the synthesis and testing of small molecule ice recrystallization inhibitors in the inhibition of methane hydrates is unprecedented and may lead to a novel class of compounds.

A multidisciplinary approach has been applied to the development of sustainable technologies for three industrially relevant projects. Reversible ionic liquids are novel carbon dioxide capture solvents. These non-aqueous silylamines efficiently capture carbon dioxide through chemical and physical absorption and release carbon dioxide with minimal addition of heat. The development of these capture agents aims to eliminate the need for a co-solvent, while minimizing energy loss and achieving solvent recyclability. Also presented is the use of carbon dioxide for amine protection during chemical syntheses. Amine protection is widely used in almost all sectors of chemical and pharmaceutical industries. The use of carbon dioxide as a reversible protecting group reduces solvent waste during protection and deprotection and improves the atom economy of existing processes. Sustainable chemistry has also been applied to the use of reversible ionic liquids as switchable surfactants for nanoparticle synthesis. The reversible ionic liquid system offers two significant advantages toward a more efficient synthesis and deposition of nanoparticles in that an additional surfactant is not required, and due to the reversible nature of the ionic liquids, a facile and waste-reduced deposition method exists.

Chapter 1 contains an Introduction to the role of metal complexes in functional assemblies. The remainder of the chapter is devoted to an Introduction to the

Diss. (sammanfattning) Uppsala : Univ., 2004. / Härtill 4 uppsatser.

Thesis (M.S.P.H.)--University of Michigan, 1941.

Inaug.-Diss.--Basel. / Curriculum vitae.

Inaug.-Diss.--Basel. / Curriculum vitae.

Thesis (M.S.P.H.)--University of Michigan, 1941.