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Full-Text Articles in Physical Sciences and Mathematics
Computational Quantum Chemistry Studies Of The Stabilities Of Radical Adducts Formed During The Oxidation Of Melatonin Derivatives, James Horne
Electronic Theses and Dissertations
Melatonin is a natural antioxidant that has been investigated for properties as a potential spin trap to identify short-lived free radicals. Computational quantum chemistry studies have been performed for the oxidation of melatonin to N1-acetyl-N2-formyl-5-methoxykynuramine. This research focused on modification of melatonin into derivatives and analyzing the change in total molecular energy from melatonin to its oxidation product, as well as the corresponding derivatives. Each of the molecular geometries were optimized at the DFT/B3LYP/6-31G(d), DFT/B3LYP/cc-pVXZ (X = D, T), HF/6-31G(d), HF/cc-PVXZ (X = D, T), MP2/6-31G(d), and MP2/cc-PVXZ (X = D, T) levels of theory. …
Advances In Structure Elucidation Of Small Molecules And Peptides By Nuclear Magnetic Resonance Spectroscopy And Mass Spectrometry, Ryan D. Cohen
Advances In Structure Elucidation Of Small Molecules And Peptides By Nuclear Magnetic Resonance Spectroscopy And Mass Spectrometry, Ryan D. Cohen
Seton Hall University Dissertations and Theses (ETDs)
This dissertation reports on improvements in nuclear magnetic resonance (NMR) and mass spectrometry (MS) structure determination methods of organic compounds, with particular focus on challenging cyclic peptides. A recent and important innovation in NMR spectroscopy is the combination of theoretical property predictions, such as chemical shifts, using density functional theory (DFT) to aid in challenging NMR structure assignments, such as determination of regio- and stereo-configurations. In the first part of this thesis, a comprehensive benchmark study of DFT chemical shift prediction methods was performed using experimental NMR data collected from 50 well curated compounds, which was referred to as the …
Quantum Mechanical Studies Of Water Splitting Reaction With (Zno)3 Nanoclusters As Catalysts, Duwage C. Perera
Quantum Mechanical Studies Of Water Splitting Reaction With (Zno)3 Nanoclusters As Catalysts, Duwage C. Perera
Electronic Theses and Dissertations
With the current energy crisis, H2 production through the water-splitting reaction has drawn attention recently. In this thesis, I studied the structural (geometry) and electronic properties (vertical detachment energy and electron affinity) of ZnO monomers and dimers using density functional theory. ZnO is a metal oxide with a 3.37 eV band gap and can be a commercially cheaper photocatalyst in hydrogen (H2) production. The B3LYP/DGDZVP2 pair was selected after investigating different pairs of exchange functionals and basis sets to study the hydration, hydrolysis, and water-splitting reaction. The singlet-triplet energy gaps of small (ZnO)n clusters (n=1-6) of …