Inorganic Chemistry Commons^™

Elucidation Of Spin-Hamiltonian Parameters Via Spectroscopy, Magnetization, And Computation, Joshua C. Mengell

Chemistry and Chemical Biology ETDs

Molecular Quantum Information Science (QIS) is fundamentally concerned with using spin-systems as quantum bits (qubits) or as sensors. Prerequisite to using molecular systems for QIS applications, it must be understood how one can design molecules with bespoke magnetic characteristics. Herein we study various paramagnetic molecular compounds, describing their complex magnetic characteristics using a spin-Hamiltonian formalism. We utilize various (sometimes novel) methods for determining these spin-Hamiltonian parameters. Many of these molecules possess magnetic characteristics, which make them attractive as qubits or for sensing applications. These characteristics include higher total spin-states (qudits—S_T>1/2), forbidden interstate electronic transitions, systems of spatially distant …

Exploring The Nature And Role Of Local Cation Ordering In Disordered Rock Salt Cathodes For Li- And Na-Ion Batteries, You Wang

Chemistry and Chemical Biology ETDs

Cation-disordered rock-salt (DRX) cathodes provide a highly tunable platform for next-generation Li- and Na-ion batteries, but their electrochemical behavior is strongly influenced by local structural features hidden in average crystal structures. This dissertation systematically investigates local cation ordering in Li- and Na-based DRX cathodes to understand its effects on Li+/Na+ transport, redox activity, structural evolution, and electrochemical performance. In Li-based systems, Raman spectroscopy and electrochemical analysis reveal that local layered cation ordering in Mn- and Fe-based DRX cathodes is closely correlated with electrochemical behavior. Over-stoichiometric Li-based DRX oxyfluorides further demonstrate that excess Li can regulate local cation ordering, improve Li+ …

Theoretical And Spectroscopic Insights Into Molybdenum- And Tungsten-Sulfur Bonding, Jesse Lepluart

Chemistry and Chemical Biology ETDs

Molybdenum and tungsten chemistry in biology is dominated by bonding interactions with sulfur and the other chalcogens. The highly-conserved structures of these enzymes’ active sites suggest an early evolution in the history of life, with molybdenum and/or tungsten enzymes likely expressed by the last universal common ancestor. Despite their active site similarities, molybdenum and tungsten enzymes catalyze a diverse array of reactions via equally diverse mechanisms. A deep understanding of the electronic structures of these enzyme active sites and their catalytic intermediates is key to understanding this remarkable chemistry.

The work presented here aims to deepen the understanding of molybdenum …

Methods Of Magneto-Optical Spectroscopy And Analysis For Porphyrins And Polymer Thin-Films, Emigdio E. Turner

Chemistry and Chemical Biology ETDs

This dissertation describes the construction of two high precision magneto-polarimeters for performing Faraday rotation and Magnetic Circular Dichroism (MCD) measurements of polymer thin-films. There is a focus in materials science on the development of thin-film magneto-optically active materials. These materials could allow for the construction of a thin-film optical diode, an important device for next-generation photonic technology. Upon completion of the Faraday rotation spectrometer, two publications were generated from Faraday rotation measurements of novel polymer thin-film materials.

With growing interest by materials scientists in magneto-optically active transition-metal containing materials, an MCD spectrometer was constructed to study these materials. This spectrometer …

Studies Of The Rectification Behavior Of The Pdt Ligand And The Active Site Of Msrp, Laura J. Ingersol

Chemistry and Chemical Biology ETDs

Molybdenum (Mo) is an essential element that plays an important role in global nitrogen, carbon, and sulfur cycles with a critical role in human metabolism and ecological balance. It becomes catalytically active when complexed with the pyranopterin dithiolene ligand (PDT), forming the nearly ubiquitous molybdenum cofactor (Moco). The complex biosynthetic pathway of Moco, its presence in all three domains of life, and its role as a constituent cofactor in the last universal common ancestor (LUCA) all point toward the importance of the PDT in the development of life on Earth. Molybdoenzymes catalyze the two-electron oxidation or reduction of substrates that …

Small Molecule Analog Studies Of Paramagnetic Dmso Reductase Enzyme Family Intermediates, Khadanand Kc

Chemistry and Chemical Biology ETDs

Pyranopterin molybdenum and tungsten enzymes are expressed in numerous organisms from all domains of life. These enzymes catalyze a variety of atom, hydride, and electron transfer reactions. The enzymes are of great importance in the biogeochemical cycles of nitrogen, carbon, and sulfur. In recent years, chemists have investigated applications for some of these enzymes as industrial biocatalysts. The dimethylsulfoxide reductase (DMSOr) enzyme family is the broadest family of pyranopterin Mo enzymes. The first coordination sphere of the Mo or W-containing active site for each member of this family is made up of 4 sulfur donors from the two pyranopterin dithiolenes …

Development Of Ni-Catalyzed Alkene Dicarbofunctionalization Reactions, Shekhar Kc

Chemistry and Chemical Biology ETDs

Alkenes serve as one of the most important feedstocks for organic synthesis, having two vicinal sites for bond formation. In alkenes, both vicinal sites can be functionalized with two reagents in a process commonly known as alkene difunctionalization, which results in the formation of two new bonds. A number of alkenes difunctionalization reactions, such as diamination, dioxygenation, carboamination and carbooxygenation, are known. However, difunctionalization of alkenes with two carbon-based entities, termed alkene dicarbofunctionalization, is relatively less common. Development of such a process could provide a powerful method to introduce two different carbon fragments across an alkene in a regioselective manner, …

Detection Of Salen-Type Tracers For Subterranean Fluid Flow Monitoring Using Surface-Enhanced Raman Spectroscopy, Jenny C. Sanchez

Chemistry and Chemical Biology ETDs

A series of hydrocarbon and aqueous soluble salen-type ligands have been synthesized and characterized by electronic and vibrational spectroscopy. Aqueous soluble salen-type ligands were complexed to a metal and investigated as potential underground fluid flow tracers using Surface-Enhanced Raman Spectroscopy (SERS) as the analytical technique. Vibrational spectra obtained from SERS was shown to have enhanced the spectral signal for these complexes in low concentrations though did not show significant differences between the free ligands and their metal complexes. This research has shown that, with some structural modifications, salen-type ligands can be effective candidates as subterranean fluid flow tracers when SERS …

Systematic Size Control In The Synthesis Of Zero-Valent Iron Nanoparticles, Grant C. Bleier

Chemistry and Chemical Biology ETDs

A novel synthetic method for the production of highly magnetic, low size-dispersity nanoparticles through reversible magnetic agglomeration is introduced and studied in detail. Initially, a weakly coordinating surfactant (3-octadecyl-2,4-pentanedione) is employed to produce a wide range of nanoparticle sizes ranging from 8 to 20 nm in diameter. The kinetics faced in these reactions by cheap and widely available iron complex precursors can be avoided in this method with the introduction of thermodynamic control, which occurs in the form of a magnetic precipitation event that essentially halts nanoparticle growth. Utilizing this synthetic method, the length of the alkyl chain on the …

Synthesis, Characterization, And Spectroscopy Of Donor-Acceptor Charge Transfer Complexes, Dominic Kofi Kersi

Chemistry and Chemical Biology ETDs

A series of square-planar metal (diimine)(dichalcogenolene) chromophoric complexes have been synthesized, characterized and studied spectroscopically. Studies conducted on diimineplatinum(II) dichalcogenolene complexes (LPtL’) using time resolved spectroscopic techniques such as transient absorption and emission, reveal a charge-separated excited state of the type dichalcogenolene → diimine charge-transfer (LL’CT) [(dichalcogenolene^•+)Pt(diimine^•-) with an open shell donor-acceptor biradical character. This makes the low-energy ligand-to-ligand charge-transfer (LL’CT), or the mixed-metal ligand-to-ligand charge-transfer (MMLL’CT), transitions of diimineplatinum(II) dichalcogenolene complexes particularly interesting to us in facilitating our knowledge of biradical charge-separated states. Long-live excited state lifetimes were observed for these complexes upon visible photoexcitation …