Master of Science, Miami University, 2024, Chemistry and Biochemistry

The bulky ligand, 2,6-bis-(3',5'-diphenylpyrazolyl)pyridine (bdppp), was attached to Co(II) to produce the two complexes, [Co(bdppp)Cl2] and [Co(bdppp)2](BF4)2. Both complexes were studied by X-ray crystallography, UV-vis, EPR, Evans (NMR) susceptibility, and variable temperature NMR to discover how the bulky phenyls on the 3 and 5 positions of the pyrazole rings change the structure of the complex. [Co(bdppp)Cl2] was found to have a trigonal bipyramidal geometry and [Co(bdppp)2](BF4)2 had a pseudo-octahedral geometry. The two structures were found to be surprisingly similar electronically, with the magnetic z-axis in the direction of the Co-Npy bonds in both complexes, which were high-spin in solution at all tested temperatures.

Committee: David Tierney (Committee Chair); Rock Mancini (Committee Member); Michael Crowder (Committee Member); Carole Dabney-Smith (Committee Member) Subjects: Chemistry; Inorganic Chemistry

Bachelor of Sciences, Ohio University, 2021, Chemistry and Biochemistry

Several procedures were carried out to synthesize the "scorpionate" trispyrazole (Tp) complexes [(Tp*)Ni(II)(PyPz)], [(Tp*)Fe(II)(PyPz)], and [(Tp*)Fe(II)(PyPzH)]PF6, using the ligands 3-(2-pyridyl)pyrazolate (PyPz), 3-(2-pyridyl)pyrazole (PyPzH), and hydrotris(3,5-dimethylpyrazolyl)borate (Tp*). These ligands are highly flexible in both their chelating and substituent properties, opening the way for complexes that can be modified for various applications; for example, [(Tp*)Fe(II)(PyPz)] and [(Tp*)Fe(II)(PyPzH)]PF6 are potentially useful for catalyzing nitrene transfer reactions. All ligands were successfully synthesized. The synthesis of the nickel complex [(Tp*)Ni(II)(PyPz)] was also successful. However, several attempts to form half-sandwich scorpionate iron complexes [(Tp*)Fe(II)(PyPz)] and [(Tp*)Fe(II)(PyPzH)]PF6 resulted in the formation of the sandwich compound [(Tp*)2Fe(II)]. Future modifications and strategies that may lead to [(Tp*)Fe(II)(PyPz)] are discussed based on these attempts and the current data. The synthesized compounds were characterized by FTIR and 1H NMR spectroscopy. [(Tp*)Ni(II)(PyPz)] was found to have a slightly distorted geometry that may have a planar shape between the PyPz ligand and the two arms of the Tp* ligand.

Committee: Michael Jensen PhD (Advisor) Subjects: Chemistry; Inorganic Chemistry

Doctor of Philosophy, Case Western Reserve University, 2014, Chemistry

Cancer, a major health issue in the United States, is the second leading cause of death after disease of heart. The formation of new blood vessels, known as angiogenesis, which new capillaries sprout from the existing vessels, is believed to promote the tumor growth. Due to the dependence of tumor progression on angiogenesis, it has been an interesting field in the search of antiangiogenesis agents which stop the progression of tumor formation and also different types of receptors accounting for angiogenesis by the ever-evolving positron emission tomography (PET) technology. Phospholipids oxidation in biological systems contributes to diverse pathological processes and is also believed to introduce age-related diseases. Oxidative cleavage of phospholipids containing docosahexaenoic acid (DHA) yields the reactive electrophilic species such as 4-hydroxy-7-oxohept-enoates (HOHA) which would later on covalently bond to e-amino group of protein lysine residue and turn into the 2-(¿-carboxyethyl)pyrrole (CEP) protein adducts. The CEP adducts is found to be associated with age-related macular degeneration (AMD) by triggering the angiogenesis in the retina. Recent study also revealed the novel molecular pattern between CEP adducts and Toll-like receptor 2 (TLR2) which leads to the angiogenesis response. And it provides an alternative therapeutic target especially in cases cancers resistant to the conventional anti-VEGF therapy. Therefore it is necessary to synthesize the gamma radioactive isotope labeled CEP adducts and apply them for the targeting of TLR2 with PET imaging technique. A convenient synthesis of putative fluorine-18-labeled-CEP was achieved with satisfied yields and the fluorination condition was optimized as well because limited half-life of fluorine-18 (109.7min) required the reaction to be accomplished in a short time-frame. Meanwhile in order to overcome the limited stability of CEP adducts which prevents its long-term usage as standards in immunosorbent (open full item for complete abstract)

Committee: Robert Salomon (Advisor); Irene Lee (Committee Chair); Gregory Tochtrop (Committee Member); Rajesh Viswanathan (Committee Member); Yanming Wang (Committee Member) Subjects: Analytical Chemistry; Biochemistry; Organic Chemistry

PhD, University of Cincinnati, 2008, Arts and Sciences : Chemistry

A detailed study involving platinum(II) compounds with bis-2,6-pyrazolyl-phenyl type ligands have been undertaken in an effort to design a new architecture for building macrocyclic molecules with potentially coordinating tridentate ligands. Initial reports focused on platinum complexes with 2,6-bis-pyrazolyl-pyridine ligands. One complex, Pt(bpp)Ph +, exhibited an intense pink emission of the solid at 77 K, which is one of the first examples of a luminescent platinum compound with a bis-pyrazolyl-pyridine ligand. Herein we report the investigation of steric influence to promote C-H activation on the formation of monomeric and macrocyclic platinum(II) complexes, using methyl substituents on a series of anionic bis-pyrazolyl-phenyl ligands. Further studies of concentrated reaction mixtures at long reaction times result in exclusively trimeric products, whereas more dilute mixtures and shorter reaction times give only monomer products. Thus, careful control of the reaction conditions allows for selective activation of C-H bonds on the ligand giving isolated products of expected monomers and trimers, as well as surprising new dimeric products. In the course of our investigations of the monomeric platinum(II) products, we have discovered that four complexes react with dithiocarbamate accelerators most commonly used in latex processing, giving a colored response. Thus, the platinum complexes can be used as colorimetric indicators to detect allergenic dithiocarbamate compounds in latex products. In addition, we describe the synthesis and preliminary characterization of a potential two-electron reagent using a monomeric complex, Pt(4)Cl, and pip 2NNN, where 4 is 1,3-bis(3,5-dimethylpyrazolyl)benzene and (pip 2NNN) is 2,6-bis(piperidylmethyl)pyridine, to give Pt(4)(pip 2NNN) +.

Committee: William Connick (Advisor) Subjects: Chemistry, Inorganic