Doctor of Philosophy, University of Akron, 2024, Polymer Science

The large carbon footprint of plastic production and the detrimental environment impact of plastic waste demand sustainable substitutes for current non-degradable, fossil-based polymeric materials. Transition-metal catalyzed carbonylative polymerization (COP) offers a methodology to introduce organic carbonyl functional groups to the backbone of polymers in a potentially sustainable way. The organic carbonyl groups bring about degradability under various conditions that are met on the surface of earth. Utilizing carbon monoxide as a cost-effective, low-carbon footprint starting material is key to this process. Carbonylative polymerizations of olefins catalyzed by Pd catalysts have been well-studied since the 1960s. This dissertation studies the development of Ni catalysts for carbonylative polymerizations of olefins. A particular emphasis will be catalyst development to incorporate “defects” in the backbone of alternating CO-ethylene copolymer to improve processibility and mechanical properties of the polymer products. An overview of transition-metal catalyzed carbonylative polymerization will be provided in Chapter I. Chapter II will discuss our zwitterionic Ni catalysts for alternating copolymerization of CO and ethylene. Chapter III will explore new catalyst designs to achieve the non-alternating copolymerization of CO and ethylene. Chapter IV will discuss a novel family of Ni catalysts that are capable of catalyzing the terpolymerization of CO, ethylene and propylene.

Committee: Li Jia (Advisor); James Eagan (Committee Chair); Christopher Ziegler (Committee Member); Kevin Cavicchi (Committee Member); Junpeng Wang (Committee Member) Subjects: Chemistry; Materials Science; Organic Chemistry

PhD, University of Cincinnati, 2004, Arts and Sciences : Chemistry

Ni(II) complexes containing amidates and thiolates have been shown to react with O2 via irreversible ligand oxidation. We have constructed a series of Ni(II) complexes based on a tripodal amine bis(oxime) ligand framework. These complexes display oxygen reactivity upon deprotonation of the oximes without requiring irreversible ligand oxidation. This project investigated the reaction involving one of the complexes in the library, [Ni(TRISOXH 3 )(NO 3 )(H 2 O)](NO 3 )· (H 2 O), where TRISOXH 3 = (tris(1-propan-2-onyl oxime)amine). It was discovered that the reaction of this complex with molecular oxygen is contingent upon the presence of a source of hydrogen atoms. This two-hydrogen atom donor acts as a substrate. Several primary alcohols, including the relatively inert methanol, and amines were catalytically oxidized by this reaction. Spectroscopic analysis using a variety of techniques has demonstrated that reversible oxidation occurs on the oximate nitrogen to form an iminoxyl radical. Many of the other complexes in the series were also investigated to examine their electronic structure, their electrochemical properties, and their ability to oxidize methanol.

Committee: Dr. Michael Baldwin (Advisor) Subjects: Chemistry, Inorganic

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2005, Photochemical Sciences

Metallo-tetrapyrroles (MTP) are highly stable macrocyclic ð-systems that display interesting properties that make them potential candidates for various applications. Among these applications are optoelectronics, magnetic materials, photoconductive materials, non-linear optical materials and photo tumor therapeutic drugs. These applications are generally related to their high stability and efficient light absorption ability in the visible and near-infrared region of the optical spectrum. Metallo porphyrins are well known and widely studied representatives of metallotetrapyrroles. Electron deficient substituents in the meso positions are well known to greatly influence the interaction between the metal d-orbitals and the nitrogen orbitals of the tetrapyrrole macrocycle. In this work, a series of electron deficient porphyrins has been studied to gain some knowledge about the change in the excited state dynamics with structural and electronic modifications. Among these porphyrins is nickel and iron modified species bearing perfluoro-, perprotio-, p-nitrophenyl- and perfluorophenyl- meso substituents. Ultrafast transient absorption spectrometry has been used as the main research instrument along with other spectroscopic and electrochemical methods.

Committee: Michael Rodgers (Advisor) Subjects: