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Full-Text Articles in Chemistry

Photoluminescence Switching In Quantum Dots Connected With Fluorinated And Hydrogenated Photochromic Molecules, Ephraiem S. Sarabamoun, Jonathan M. Bietsch, Pramod Aryal, Amelia G. Reid, Maurice Curran, Grayson Johnson, Esther H. R. Tsai, Charles W. Machan, Guijun Wang, Joshua J. Choi Jan 2024

Photoluminescence Switching In Quantum Dots Connected With Fluorinated And Hydrogenated Photochromic Molecules, Ephraiem S. Sarabamoun, Jonathan M. Bietsch, Pramod Aryal, Amelia G. Reid, Maurice Curran, Grayson Johnson, Esther H. R. Tsai, Charles W. Machan, Guijun Wang, Joshua J. Choi

Chemistry & Biochemistry Faculty Publications

We investigate switching of photoluminescence (PL) from PbS quantum dots (QDs) crosslinked with two different types of photochromic diarylethene molecules, 4,4'-(1-cyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (1H) and 4,4'-(1-perfluorocyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] (2F). Our results show that the QDs crosslinked with the hydrogenated molecule (1H) exhibit a greater amount of switching in photoluminescence intensity compared to QDs crosslinked with the fluorinated molecule (2F). With a combination of differential pulse voltammetry and density functional theory, we attribute the different amount of PL switching to the different energy levels between 1H and 2F molecules which result in different potential barrier …


Computational Investigation Of Mononuclear Iron Water Oxidation Catalyst Design, Kristal Stevens, Emily Jarvis Oct 2023

Computational Investigation Of Mononuclear Iron Water Oxidation Catalyst Design, Kristal Stevens, Emily Jarvis

Chemistry and Biochemistry Faculty Works

Hydrogen production from non-carbon sources is an essential component of clean and sustainable technology for reducing greenhouse gas emissions from fuels. Water oxidation, which splits water molecules into hydrogen (protons) and molecular oxygen, is a thermodynamically challenging, multistep reaction achieved in photosynthetic organisms via photocatalysis by the Oxygen Evolving Complex (OEC) of Photosystem II. Mononuclear water oxidation catalysts that aim to mimic nature typically rely on heavy, rare metals such as ruthenium and iridium. Replacing these metals with iron is particularly appealing because it is abundant, benign, and inexpensive. We use density functional theory to characterize the catalytic ability of …


Halogen Bonding Interactions Of Haloaromatic Endocrine Disruptors And The Potential For Inhibition Of Iodothyronine Deiodinases, Craig A. Bayse Jan 2023

Halogen Bonding Interactions Of Haloaromatic Endocrine Disruptors And The Potential For Inhibition Of Iodothyronine Deiodinases, Craig A. Bayse

Chemistry & Biochemistry Faculty Publications

Halogen bonding (XB) is a potential mechanism for the inhibition of the thyroid-activating/deactivating iodothyronine deiodinase family of selenoproteins through interactions with halogenated endocrine disrupting compounds (EDCs). Trends in XB interactions were examined using density functional theory for a series of polyhalogenated dibenzo-1,4-dioxins, biphenyls, and other EDCs with methylselenolate, a simple model of the Dio active site selenocysteine. The strengths of the interactions depend upon the halogen (Br>Cl), the degree of substitution, and the position of the acceptor. In terms of donor-acceptor energies, interactions at the meta position are often the strongest, suggesting a link to the topology of THs, …


The Importance Of Properly Modeling The Hydrogen Bond In Histidine, Falonne M. Tchodimo, Guoquan Zhou, Hua-Jun Fan Jan 2019

The Importance Of Properly Modeling The Hydrogen Bond In Histidine, Falonne M. Tchodimo, Guoquan Zhou, Hua-Jun Fan

Pursue: Undergraduate Research Journal

The hydrogen bond plays a vital role in many reactions. This study is to investigate the effect of different hydrogen bonding modes, such as single and double hydrogen bonds, via the quantum mechanic (QM) methods. Four histidine models (A, B, C, and D) with different numbers of intra-molecular hydrogen bonds were studied. The QM model results indicate that the double hydrogen bond is plausible and has a more stable geometry. However, this study suggests that the data from QM methods require further evaluation with solvation models to produce an even better energy profile.


The Synthesis And Characterization Of A Magnetite Nanoparticle With Potent Antibacterial Activity And Low Mammalian Toxicity, Seyedeh Maryamdokht Taimoory, Abbas Rahdar, Mousa Aliahmad, Fardin Sadeghfar, Mohammad Reza Hajinezhad, Mohammad Jahantigh, Parisa Shahbazi, John F. Trant Sep 2018

The Synthesis And Characterization Of A Magnetite Nanoparticle With Potent Antibacterial Activity And Low Mammalian Toxicity, Seyedeh Maryamdokht Taimoory, Abbas Rahdar, Mousa Aliahmad, Fardin Sadeghfar, Mohammad Reza Hajinezhad, Mohammad Jahantigh, Parisa Shahbazi, John F. Trant

Chemistry and Biochemistry Publications

Magnetite has shown some promise as a biomedical material and antibacterial agent; however the benefits are normally only realized when it is used in combination with other metals or drugs. Unfunctionalized magnetite may be a biocompatible alternative. This report discusses the synthesis and potent antibacterial activity, with low associated mammalian organ toxicity, of nanomagnetite particles. Magnetite (Fe3O4) nanoparticles were electrochemically prepared in a green surfactant-free, closed water loop system. These materials, characterized by X-ray diffraction, FTIR, and vibrational magnetometry, also appear contaminated with Fe-O-O-H functionalities. This physical characterization is accompanied by a computational investigation of truncated clusters showing that a …


Time-Resolved Infrared Spectroscopy And Density Functional Theory Study Of Weak Interactions Of Metal Carbonyls And Organic Solvents, Carolyn Evans Sheffield Mar 2010

Time-Resolved Infrared Spectroscopy And Density Functional Theory Study Of Weak Interactions Of Metal Carbonyls And Organic Solvents, Carolyn Evans Sheffield

Theses and Dissertations

Pulsed laser flash photolysis of M(CO)6 (M = Cr, W) in cyclohexane with a small amount of benzene results in three sequential reactions. The first is the photodissociation of the parent to yield a M(CO)5:C6H12 complex, which takes place faster than the time resolution of our experiments. The second reaction is the replacement of the cyclohexane ligand with benzene to form a M(CO)5:C6H6 complex, in which benzene is coordinated to the metal via one side of the ring. This complex then falls apart in solution as M(CO)5 coordinates with a trace impurity in the solution that is likely water. Kinetic …


Temperature Dependence Of The Double Layer Capacitance For The Restricted Primitive Model Of An Electrolyte Solution From A Density Functional Approach, Douglas Henderson, J. Reszko-Zygmunt, Stefan Sokolowski, Dezso Boda Feb 2005

Temperature Dependence Of The Double Layer Capacitance For The Restricted Primitive Model Of An Electrolyte Solution From A Density Functional Approach, Douglas Henderson, J. Reszko-Zygmunt, Stefan Sokolowski, Dezso Boda

Faculty Publications

We apply a different version of the density functional theory, given by Pizio, Patrykiejew, and Sokolowski [J. Chem. Phys. 121, 11957 (2004)], for a nonuniform restricted primitive model of an electrolyte solution to evaluate the temperature dependence of the capacitance of an electric double layer. We show that this theory is capable of reproducing the computer simulation data at a quantitative level. In particular, the reversal of the temperature dependence of the capacitance at low temperatures is predicted. This phenomenon has been difficult to predict from theory. Further, this theory also leads to an accurate description of the double layer …