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Full-Text Articles in Chemistry

Computational Investigations Of The Photochemical Properties Of B12-Dependent Systems: From Solution To Enzymes., Megan Toda Mackintosh Dec 2021

Computational Investigations Of The Photochemical Properties Of B12-Dependent Systems: From Solution To Enzymes., Megan Toda Mackintosh

Electronic Theses and Dissertations

The photochemical properties of the B12 family of molecules (cobalamins = Cbls) have been known for many years yet only until the 21st century have applications for the light-sensitivity of Cbls come to the surface. Photolabile Cbls can be used for the delivery of therapeutics with spatial and temporal control, in the generation of hydroxyl radicals, and in nature, as demonstrated in the catalytic cycle of coenzyme B12-dependent photoreceptors. This dissertation describes the use of computational methods to explore the photochemical properties of Cbl systems including antivitamins B12, a thiolato-cobalamin, and the coenzyme B …


Automated Parsing Of Flexible Molecular Systems Using Principal Component Analysis And K-Means Clustering Techniques, Matthew J. Nwerem Aug 2021

Automated Parsing Of Flexible Molecular Systems Using Principal Component Analysis And K-Means Clustering Techniques, Matthew J. Nwerem

Computational and Data Sciences (MS) Theses

Computational investigation of molecular structures and reactions of biological and pharmaceutical interests remains a grand scientific challenge due to the size and conformational flexibility of these systems. The work requires parsing and analyzing thousands of conformations in each molecular state for meaningful chemical information and subjecting the ensemble to costly quantum chemical calculations. The current status quo typically involves a manual process where the investigator must look at each conformation, separating each into structural families. This process is time-intensive and tedious, making this process infeasible in some cases, and limiting the ability of theoreticians to study these systems. However, the …


Computational Analysis Of Type 3 Iodothyronine Deiodinase: Potential Inhibitors, Substrate Binding, And Dimer Structure, Eric Scott Marsan Jul 2021

Computational Analysis Of Type 3 Iodothyronine Deiodinase: Potential Inhibitors, Substrate Binding, And Dimer Structure, Eric Scott Marsan

Chemistry & Biochemistry Theses & Dissertations

Thyroid hormones (THs) in mammalian tissues are crucial for development and maintaining metabolic homeostasis. Iodothyronine deiodinases (Dios) remove iodines from THs by a selenocysteine (Sec) residue, which either activates or inactivates them. Halogen bonding (XB) has been proposed to describe the interaction between the Se and I atoms of the T4-Dio complex. Disruption of TH homeostasis by xenobiotics, such as polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) can cause deleterious effects on the endocrine system. Experimental studies have indicated that PBDEs and PCBs could disrupt TH homeostasis by inhibiting Dio through XB formation. However, no current quantitative study exists …


Oriented External Electric Field (Oeef) Tuning Of Unsubstituted Azoheteroarene Photoswitching Performance., Irma Avdic May 2021

Oriented External Electric Field (Oeef) Tuning Of Unsubstituted Azoheteroarene Photoswitching Performance., Irma Avdic

College of Arts & Sciences Senior Honors Theses

Azoheteroarenes are relatively new photoswitchable compounds, where one of the phenyl rings of an azobenzene molecule is replaced by a heteroaromatic five-membered ring. Although few studies have been performed, recent findings on methylated azoheteroarenes show that these photoswitches have great potential in various optically addressable applications. Thermal stability of molecular switches is one of the primary factors considered in the design process. For the purposes of quick information transmission in materials science, the thermal (Z – E) relaxation process should be as short as possible. On the other hand, molecular memory storage devices prefer long Z - E relaxation times. …


The Power Of Sulfur: A Study Of An Isothiocyanate Chiral Derivatizing Agent, Thioamide Based Chiral Solvating Agents, And The Geometry Of Sulfonamides, Emily B. Crull May 2021

The Power Of Sulfur: A Study Of An Isothiocyanate Chiral Derivatizing Agent, Thioamide Based Chiral Solvating Agents, And The Geometry Of Sulfonamides, Emily B. Crull

Dissertations

This three-part dissertation is connected by the thread of utilizing sulfur-based functional groups, hence the power of sulfur. The first project was the development of a pentafluorobenzene based isothiocyanate chiral derivatizing agent (CDA), a class of compounds that differentiate enantiomers through covalent bond formation. This project, which was addressed using a combination of synthetic and computational methods and NMR analysis, gave rise to an CDA that was highly selective for amines and computationally predictable. Branching off of that, the second project demonstrated the use of two thioamide chiral solvating agents (CSAs), which had never been reported as a core functional …


Experimental And Theoretical Investigation Of Regioselectivity For A Series Of Ketoimines With Nuclear Magnetic Resonance Spectroscopy And Density Functional Theory, Amanda Stahl, Joseph M. Fritsch, Kelsey R. Brereton Apr 2021

Experimental And Theoretical Investigation Of Regioselectivity For A Series Of Ketoimines With Nuclear Magnetic Resonance Spectroscopy And Density Functional Theory, Amanda Stahl, Joseph M. Fritsch, Kelsey R. Brereton

Seaver College Research And Scholarly Achievement Symposium

A series of ketoimines bearing pendant quinolyl substituents were prepared by Schiff base condensation of 1,3-diketones with two different substituents: trifluoromethyl and an alkyl/aryl group (e.g., Me, Et, iPr,tBu, Ph. Synthetic reactions of ketoimines with varying alkyl/aryl substituents altered the distribution of regioisomers as measured in isolated yields and detected by 1H and 19F NMR spectroscopy of crude reaction mixtures. Reaction with the least sterically encumbered diketone (CF3with Me) resulted in mixture of ketoimines with virtually quantitative formation of the ketoimine resulting from quinolyl addition to the carbonyl adjacent to the alkyl substituent. …


Not-So-Innocent Anions Determine The Mechanism Of Cationic Alkylators, S. Maryamdokht Taimoory, Vincenzo Alessandro Cataldo, Andreas Schäfer, John F. Trant, Ryan Guterman Feb 2021

Not-So-Innocent Anions Determine The Mechanism Of Cationic Alkylators, S. Maryamdokht Taimoory, Vincenzo Alessandro Cataldo, Andreas Schäfer, John F. Trant, Ryan Guterman

Chemistry and Biochemistry Publications

Alkylating reagents based on thioimidazolium ionic liquids were synthesized and the influence of the anion on the alkylation reaction mechanism explored in detail using both experimental and computational methods. Thioimidazolium cations transfer alkyl substituents to nucleophiles, however the reaction rate was highly dependent on anion identity, demonstrating that the anion is not innocent in the mechanism. Detailed analysis of the computationally-derived potential energy surfaces associated with possible mechanisms indicated that this dependence arises from a combination of anion induced electronic, steric and coordinating effects, with highly nucleophilic anions catalyzing a 2-step process while highly non-nucleophilic, delocalized anions favor a 1-step …


Mechanism Of Action Of Dihydropteridine Reductase, Gabriela Arias De La Rosa Feb 2021

Mechanism Of Action Of Dihydropteridine Reductase, Gabriela Arias De La Rosa

Dissertations, Theses, and Capstone Projects

Human dihydropteridine reductase is an enzyme that transfers a hydride from NADH to reduce quinonoid 7,8-dihydropterin (qBH2) to 5,6,7,8-tetrahydropterin (BH4), which is a cofactor important in the production of neurotransmitters.DHPR deficiency causes a drastic form of the neurological genetic disease phenylketonuria (PKU) that does not benefit from a phenylalanine-free diet.From site-directed mutagenesis studies, mostly on Rat DHPR, we know that certain residues are important for cofactor binding, substrate binding, and hydride transfer; however, there are still some questions about how DHPR works, particularly, because there is not a crystal structure of the tertiary complex: What is …


Using Nmr Spectroscopy And Computational Chemistry To Confirm The Structure Of Novel Antibiotic Nocamycin O, Stephanie Lewis Jan 2021

Using Nmr Spectroscopy And Computational Chemistry To Confirm The Structure Of Novel Antibiotic Nocamycin O, Stephanie Lewis

CMC Senior Theses

In recent years, many medically promising antibiotics have been discovered in nature, especially in insect-microbe symbioses. One of the better-studied examples of this kind of defensive relationship is that of fungus-growing ants and the antibiotic-producing Actinobacteria. These bacteria produce several defensive chemicals with myriad uses, including one antibiotic that inhibits the growth of several bacterial strains, including other Actinobacteria. This antibiotic (known as nocamycin O) is a promising candidate for medicinal use due to its similarities to bacterial RNA polymerase inhibitors tirandamycin and streptolydigin, which inhibit several human pathogens. The determination of the structure of nocamycin O will be an …


Novel Nonperipheral Octa-3-Hydroxypropylthio Substituted Metallo-Phthalocyanines: Synthesis, Characterization, And Investigation Of Their Electrochemical, Photochemical And Computational Properties, Ni̇lgün Kabay, Yasemi̇n Bayğu, Meti̇n Ak, İzzet Kara, Esra Nur Kaya, Mahmut Durmuş, Yaşar Gök Jan 2021

Novel Nonperipheral Octa-3-Hydroxypropylthio Substituted Metallo-Phthalocyanines: Synthesis, Characterization, And Investigation Of Their Electrochemical, Photochemical And Computational Properties, Ni̇lgün Kabay, Yasemi̇n Bayğu, Meti̇n Ak, İzzet Kara, Esra Nur Kaya, Mahmut Durmuş, Yaşar Gök

Turkish Journal of Chemistry

The current study describes the synthesis, electrochemical, computational, and photochemical properties of octa (3-hydroxypropylthio) substituted cobalt (II) (4), copper (II) (5), nickel (II) (6) and zinc(II) (7) phthalocyanine derivatives. These novel compounds were characterized by elemental analysis, 1H, 13C NMR, FT-IR, UV-Vis, and MS. The redox behaviors of these metallo-phthalocyanines were investigated by the cyclic voltammetric method. The optimized molecular structure and gauge-including atomic orbital (GIAO) 1H and 13C NMR chemical shift values of these phthalocyanines in the ground state had been calculated by using B3LYP/6-31G(d,p) basis set. The outcomes of the optimized molecular structure were given and compared with …