Graduation Semester and Year

2019

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Chemistry

Department

Chemistry and Biochemistry

First Advisor

Rasika Dias

Abstract

Transition-metal catalyzed direct functionalization of inert C-H and C=C bonds through nitrene- and oxo-transfer reactions are powerful and attractive synthetic strategies for constructing C-N and C-O bonds (e.g. found in amines, aziridines, alcohols, and carbonyl compounds) directly from hydrocarbon feedstocks, and have significant synthetic potential in chemical processes leading to natural products, pharmaceuticals and biologically active molecules. Chapters 2 and 3 of this work mainly focus on nitrene- and oxo-insertion chemistry catalyzed by transition metal complexes. We employed different types of fluorinated ligands to support copper and zinc metal centers. Therefore, complexes [HB(3,5-(CF3)2Pz)3]Cu(NCMe), [H2B(3,5-(CF3)2Pz)2]Cu(NCMe), [H2B(3,5-(CF3)2-4-(NO2)Pz)2]Cu(NCMe), [{(3,5-(CF3)2Pz)ZnEt}2(μ-THF)], [{(3-(CF3),5-(t-Bu)Pz)ZnEt}2(μ-THF)], [{(3,5-(i-Pr)2Pz)ZnEt}2(μ-THF)], [N{(CF3)C(C6F5)N}2]CuNCCH3, and [N{(C3F7)C(Dipp)N}2]CuNCCH3 were synthesized and characterized. These complexes were utilized as catalysts for nitrene- and oxo-transfer from iminoiodanes (e.g. PhI=NTs and PhI=NNs) and H2O2 to arenes, olefins, and polycyclic aromatic hydrocarbons (PAHs), leading to C-H bond amination, olefin aziridination and C-H bond oxidation with great efficiency and selectivity. A wide range of organic products including amines, aziridines, and quinones were obtained and fully characterized, and possible reaction mechanisms were predicted using computational studies, and deuterium isotope labeling studies. Chapter 4 of this work focuses on the chemistry of Fe(CO)5 and its analogs with coinage metal ions leading to heterometallic complexes. Heterometallic complexes have been widely studied for their unusual metal-metal bonding, structures and reactivity. They are also found to be promising catalysts in small molecule activation chemistry and other catalytic transformations (e.g. C-C and C-heteroatom coupling reactions), particularly through harnessing the cooperative effect between metal sites of different properties. Therefore, complexes [(IPr*)Au˗Fe(CO)5][SbF6] (IPr*=1,3-bis(2,6-bis(diphenylmethyl)-4-methylphenyl)imidazol-2-ylidene), [Mes3PAu˗Fe(CO)5][SbF6] (Mes=2,4,6-trimethylphenyl), [(SIPr)Au-Fe(CO)5][SbF6] (SIPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene), [(SIPr)Au-Mn(CO)5], [(SIPr)Ag-Mn(CO)5], [(IPr*)Au-NCFe(CO)4], [(SIPr)Ag-NCFe(CO)4], [(SIPr)Cu-NCFe(CO)4], and [Mes3PAu-Mn(CO)5] were prepared, characterized and studied both in terms of structure and bonding. Efforts were made to employ these heterometallic complexes as catalysts for useful catalytic transformations and small molecule activation (e.g. alkynes) chemistry.

Keywords

Transition-metal catalysis, C-H amination, C-H oxidation, C=C aziridination, Coinage metal ions, Heterometallic complexes, Fe(CO)5, Metal-metal bonding

Disciplines

Chemistry | Physical Sciences and Mathematics

Comments

Degree granted by The University of Texas at Arlington

Included in

Chemistry Commons

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