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Chemistry

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Louisiana State University

Faculty Publications

2019

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Articles 1 - 16 of 16

Full-Text Articles in Physical Sciences and Mathematics

Simultaneous Enhancement Of Near-Infrared Emission And Dye Photodegradation In A Racemic Aspartic Acid Compound Via Metal-Ion Modification, Frank R. Fronczek, Jian Xu Nov 2019

Simultaneous Enhancement Of Near-Infrared Emission And Dye Photodegradation In A Racemic Aspartic Acid Compound Via Metal-Ion Modification, Frank R. Fronczek, Jian Xu

Faculty Publications

Changing functionalities of materials using simple methods is an active area of research, as it is "green" and lowers the developing cost of new products for the enterprises. A new small molecule racemic N,N-dimethyl aspartic acid has been prepared. Its structure is determined by single-crystal X-ray diffraction. It is characterized by FTIR, XPS, 1 H NMR, and mass spectroscopy. Its near-infrared luminescence can be enhanced by the combination of metal ions, including Dy3+, Gd3+, Nd3+, Er3+, Sr3+, Y3+, Zn2+, Zr4+, Ho3+, Yb3+, La3+, Pr6+/Pr3+, and Sm3+ ions. An optical chemistry mechanism upon interaction between the sensitizer and activator is proposed. …


Simultaneous Enhancement Of Near-Infrared Emission And Dye Photodegradation In A Racemic Aspartic Acid Compound Via Metal-Ion Modification, Frank R. Fronczek, Jian Xu Nov 2019

Simultaneous Enhancement Of Near-Infrared Emission And Dye Photodegradation In A Racemic Aspartic Acid Compound Via Metal-Ion Modification, Frank R. Fronczek, Jian Xu

Faculty Publications

Changing functionalities of materials using simple methods is an active area of research, as it is "green" and lowers the developing cost of new products for the enterprises. A new small molecule racemic N,N-dimethyl aspartic acid has been prepared. Its structure is determined by single-crystal X-ray diffraction. It is characterized by FTIR, XPS, 1 H NMR, and mass spectroscopy. Its near-infrared luminescence can be enhanced by the combination of metal ions, including Dy3+, Gd3+, Nd3+, Er3+, Sr3+, Y3+, Zn2+, Zr4+, Ho3+, Yb3+, La3+, Pr6+/Pr3+, and Sm3+ ions. An optical chemistry mechanism upon interaction between the sensitizer and activator is proposed. …


Emergent Functional Behaviour Of Humic Substances Perceived As Complex Labile Aggregates Of Small Organic Molecules And Oligomers, Robert L. Cook Nov 2019

Emergent Functional Behaviour Of Humic Substances Perceived As Complex Labile Aggregates Of Small Organic Molecules And Oligomers, Robert L. Cook

Faculty Publications

The structural organisation of humic substances (HS) has been a central question of earth sciences for several decades. The latest experimental results have led to the recognition of HS as complex mixtures of small molecules and oligomers. We investigate the correlation between the chemical composition of HS, perceived as labile aggregates, and the emergent functions. Computational modelling was used to help to understand the processes and mechanisms on the molecular scale that occur in different fractions of the HS, fulvic acids (FA) and humic acids (HA), as they interact with metal ions and organic pollutants. The importance of non-covalent interactions …


Detection Of Chalk In Single Kernels Of Long-Grain Milled Rice Using Imaging And Visible/Near-Infrared Instruments, Christopher K. Addison Nov 2019

Detection Of Chalk In Single Kernels Of Long-Grain Milled Rice Using Imaging And Visible/Near-Infrared Instruments, Christopher K. Addison

Faculty Publications

Background and objectives To maintain the competitiveness of U.S. long-grain rice in U.S. and foreign markets, having translucent whole milled grain is critical. An objective technique to detect grain chalk, opaque areas in the grain, will provide breeders and industry with an effective tool for developing low-chalk varieties or agronomic practices that reduce chalk occurrence. Two instruments developed at the Center for Grain and Animal Health Research, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), a single-kernel near-infrared (SKNIR) tube instrument and a silicon-based light-emitting diode (SiLED) high-speed sorter, were compared with two commercially available imaging instruments, WinSEEDLE and SeedCount used …


Pyrenylpyridines: Sky-Blue Emitters For Organic Light-Emitting Diodes, Thenahandi Prasanthi Deepthika De Silva, Sang Gill Youm, Isiah M. Warner Oct 2019

Pyrenylpyridines: Sky-Blue Emitters For Organic Light-Emitting Diodes, Thenahandi Prasanthi Deepthika De Silva, Sang Gill Youm, Isiah M. Warner

Faculty Publications

A novel sky-blue-emitting tripyrenylpyridine derivative, 2,4,6-tri(1-pyrenyl)-pyridine (2,4,6-TPP), has been synthesized using a Suzuki coupling reaction and compared with three previously reported isomeric dipyrenylpyridine (DPP) analogues (2,4-di(1 pyrenyl)pyridine (2,4-DPP), 2,6-di(1-pyrenyl)pyridine (2,6-DPP), and 3,5-di(1-pyrenyl)-pyridine (3,5-DPP)). 0 revealed by single-crystal X-ray analysis and computational simulations, all compounds possess highly twisted conformations in the solid state with interpyrene torsional angles of 42.3 degrees-57.2 degrees. These solid-state conformations and packing variations of pyrenylpyridines could be correlated to observed variations in physical characteristics such as photo/thermal stability and spectral properties, but showed only marginal influence on electrochemical properties. The novel derivative, 2,4,6-TPP, exhibited the lowest degree …


Pyrenylpyridines: Sky-Blue Emitters For Organic Light-Emitting Diodes, Thenahandi Prasanthi Deepthika De Silva, Sang Gill Youm, Isiah M. Warner Oct 2019

Pyrenylpyridines: Sky-Blue Emitters For Organic Light-Emitting Diodes, Thenahandi Prasanthi Deepthika De Silva, Sang Gill Youm, Isiah M. Warner

Faculty Publications

A novel sky-blue-emitting tripyrenylpyridine derivative, 2,4,6-tri(1-pyrenyl)-pyridine (2,4,6-TPP), has been synthesized using a Suzuki coupling reaction and compared with three previously reported isomeric dipyrenylpyridine (DPP) analogues (2,4-di(1 pyrenyl)pyridine (2,4-DPP), 2,6-di(1-pyrenyl)pyridine (2,6-DPP), and 3,5-di(1-pyrenyl)-pyridine (3,5-DPP)). 0 revealed by single-crystal X-ray analysis and computational simulations, all compounds possess highly twisted conformations in the solid state with interpyrene torsional angles of 42.3 degrees-57.2 degrees. These solid-state conformations and packing variations of pyrenylpyridines could be correlated to observed variations in physical characteristics such as photo/thermal stability and spectral properties, but showed only marginal influence on electrochemical properties. The novel derivative, 2,4,6-TPP, exhibited the lowest degree …


Fisetin, A 3,7,3 ',4 '-Tetrahydroxyflavone Inhibits The Pi3k/Akt/Mtor And Mapk Pathways And Ameliorates Psoriasis Pathology In 2d And 3d Organotypic Human Inflammatory Skin Models, Konstantin G. Kousoulas Sep 2019

Fisetin, A 3,7,3 ',4 '-Tetrahydroxyflavone Inhibits The Pi3k/Akt/Mtor And Mapk Pathways And Ameliorates Psoriasis Pathology In 2d And 3d Organotypic Human Inflammatory Skin Models, Konstantin G. Kousoulas

Faculty Publications

Psoriasis is a chronic immune-mediated skin disease that involves the interaction of immune and skin cells, and is characterized by cytokine-driven epidermal hyperplasia, deviant differentiation, inflammation, and angiogenesis. Because the available treatments for psoriasis have significant limitations, dietary products are potential natural sources of therapeutic molecules, which can repair the molecular defects associated with psoriasis and could possibly be developed for its management. Fisetin (3,7,3 ',4 '-tetrahydroxyflavone), a phytochemical naturally found in pigmented fruits and vegetables, has demonstrated proapoptotic and antioxidant effects in several malignancies. This study utilized biochemical, cellular, pharmacological, and tissue engineering tools to characterize the effects of …


Approaches For Sample Characterization And Lithography With Nanoparticles Using Modes Of Scanning Probe Microscopy, Jayne C. Garno, Temitope O. Jegede, Kathryn B. Mckee, Melissia Porter, Autumn E. Webb, Jin Gyun Lee, Neepa Mk Kuruppu Arachchige, Justin R. Ragains, Noémie Elgrishi Jun 2019

Approaches For Sample Characterization And Lithography With Nanoparticles Using Modes Of Scanning Probe Microscopy, Jayne C. Garno, Temitope O. Jegede, Kathryn B. Mckee, Melissia Porter, Autumn E. Webb, Jin Gyun Lee, Neepa Mk Kuruppu Arachchige, Justin R. Ragains, Noémie Elgrishi

Faculty Publications

Measurement and imaging modes of scanning probe microscopy (SPM) have been routinely applied for characterizing systems of nanoparticles; however the evolution of fabrication methods to prepare arrangements of nanoparticles remains a challenge. Reproducible fabrication of surface structures which integrate nanoparticles within ultra-small patterns will require innovative approaches to achieve high throughput and precision. Strategies for nanoscale lithography have been introduced for preparing defined arrangements of nanoparticles on surfaces based on physical or chemical interactions. For example, physisorption was employed for attaching nanoparticles based on colloidal lithography and site-directed assembly. Microfabricated atomic force microscope (AFM) tips with capillary channels have been …


A New Magnetic Topological Quantum Material Candidate By Design, Weiwei Xie, Xin Gui May 2019

A New Magnetic Topological Quantum Material Candidate By Design, Weiwei Xie, Xin Gui

Faculty Publications

Magnetism, when combined with an unconventional electronic band structure, can give rise to forefront electronic properties such as the quantum anomalous Hall effect, axion electrodynamics, and Majorana fermions. Here we report the characterization of high-quality crystals of EuSn2P2, a new quantum material specifically designed to engender unconventional electronic states plus magnetism. EuSn2P2 has a layered, Bi2Te3-type structure. Ferromagnetic interactions dominate the Curie-Weiss susceptibility, but a transition to antiferromagnetic ordering occurs near 30 K. Neutron diffraction reveals that this is due to two-dimensional ferromagnetic spin alignment within individual Eu layers and antiferromagnetic alignment between layers-this magnetic state surrounds the Sn-P layers …


Multiplexed Paper Microfluidics For Titration And Detection Of Ingredients In Beverages, Manas Ranjan Gartia, Alisha Prasad Mar 2019

Multiplexed Paper Microfluidics For Titration And Detection Of Ingredients In Beverages, Manas Ranjan Gartia, Alisha Prasad

Faculty Publications

Food safety and access to systematic approaches for ensuring detection of food hazards is an important issue in most developing countries. With the arrival of paper-based analytical devices (mu PADs) as a promising, rapid, easy-to-use, and low-cost analytical tool, we demonstrated a simple microfluidic-based titration study for the analysis of packaged fruit juices. Similar, to the titration experiments using traditional glassware in chemistry laboratories, in this study the titration experiments were developed using paper microfluidics for the analysis of several analytes such as pH, vitamin C, sugars, and preservatives present in the packaged fruit juices. The allergen found commonly in …


Bioassay-Guided Isolation And Structure Elucidation Of Fungicidal And Herbicidal Compounds From Ambrosia Salsola (Asteraceae), Frank R. Fronczek Mar 2019

Bioassay-Guided Isolation And Structure Elucidation Of Fungicidal And Herbicidal Compounds From Ambrosia Salsola (Asteraceae), Frank R. Fronczek

Faculty Publications

The discovery of potent natural and ecofriendly pesticides is one of the focuses of the agrochemical industry, and plant species are a source of many potentially active compounds. We describe the bioassay-guided isolation of antifungal and phytotoxic compounds from the ethyl acetate extract of Ambrosia salsola twigs and leaves. With this methodology, we isolated and identified twelve compounds (four chalcones, six flavonols and two pseudoguaianolide sesquiterpene lactones). Three new chalcones were elucidated as (S)-beta-Hydroxy-2,3,4,6'-tetrahydroxy-5-methoxydihydrochalcone (salsolol A), (S)-beta-Hydroxy-2',4,4',6'-tetrahydroxy-3-methoxydihydrochalcone (salsolol B), and (R)-alpha, (R)-beta-Dihydroxy-2,3,4,4,6'-pentahydroxydihydrochalcone (salsolol C) together with nine known compounds: balanochalcone, six quercetin derivatives, confertin, and neoambrosin. Chemical structures were determined …


Realization Of A Type-Ii Nodal-Line Semimetal In Mg3bi2, Weiwei Xie Feb 2019

Realization Of A Type-Ii Nodal-Line Semimetal In Mg3bi2, Weiwei Xie

Faculty Publications

Nodal-line semimetals (NLSs) represent a new type of topological semimetallic phase beyond Weyl and Dirac semimetals in the sense that they host closed loops or open curves of band degeneracies in the Brillouin zone. Parallel to the classification of type-I and type-II Weyl semimetals, there are two types of NLSs. The type-I NLS phase has been proposed and realized in many compounds, whereas the exotic type-II NLS phase that strongly violates Lorentz symmetry has remained elusive. First-principles calculations show that Mg3Bi2 is a material candidate for the type-II NLS. The band crossing is close to the Fermi level and exhibits …


Surface Coupling Of Octaethylporphyrin With Silicon Tetrachloride, Jayne C. Garno, Phillip C. Chambers, Neepa M. K. Kuruppu Arachchige, Ashley M. Taylor Feb 2019

Surface Coupling Of Octaethylporphyrin With Silicon Tetrachloride, Jayne C. Garno, Phillip C. Chambers, Neepa M. K. Kuruppu Arachchige, Ashley M. Taylor

Faculty Publications

The surface assembly of 2,3,7,8,12,13,17,18-octaethylporphyrin (OEP) using silicon tetrachloride as a coupling agent was investigated using atomic force microscopy (AFM). Nanopatterned films of Si-OEP were prepared by protocols of colloidal lithography to evaluate the morphology, thickness, and molecular orientation for samples prepared on Si(111). The natural self-stacking of porphyrins can pose a challenge for molecular patterning. When making films on surfaces, porphyrins will self-associate to form co-planar configurations of random stacks of molecules. There is a tendency for the flat molecules to orient spontaneously in a side-on arrangement that is mediated by physisorption to the substrate as well as by …


Immobilization Adjusted Clock Reaction In The Urea-Urease-H+ Reaction System, John A. Pojman Jan 2019

Immobilization Adjusted Clock Reaction In The Urea-Urease-H+ Reaction System, John A. Pojman

Faculty Publications

The bell-shaped reactivity-pH curve is the fundamental reason that the temporal programmable kinetic switch in clock reactions can be obtained in bio-competitive enzymatic reactions. In this work, urease was loaded on small resin particles through ionic binding. Experimental results reveal that the immobilization not only increased the stability of the enzyme and the reproducibility of the clock reaction, but also shifted the bell-shaped activity curve to lower pHs. The latter change enables the clock reaction to occur from an initial pH of 2.3, where the free enzyme had already lost its activity. Two mechanisms explain the influence of the immobilization …


Fluorescence-Based Ratiometric Nanosensor For Selective Imaging Of Cancer Cells, Isiah M. Warner, Kelsey E. Mcneel, Noureen Siraj, Nimisha Bhattarai Jan 2019

Fluorescence-Based Ratiometric Nanosensor For Selective Imaging Of Cancer Cells, Isiah M. Warner, Kelsey E. Mcneel, Noureen Siraj, Nimisha Bhattarai

Faculty Publications

Herein, we report the synthesis and characterization of a nanosensor developed from a group of uniform materials based on organic salts (GUMBOS). This sensor is composed of three ionic species, namely, fluorescein, rhodamine B, and tetradecyltrihexyl phosphonium (P-66614) ions. Nanoparticles prepared from this three-component GUMBOS, termed nanoGUMBOS, exhibited increased fluorescence at two wavelengths with increases in pH values. The ratio of fluorescence emission corresponding to FL and RhB components of these nanoGUMBOS also changed with pH, allowing ratiometric analysis of pH through fluorescence measurements. Peak ratios were significantly different at pH 5 and pH 7, indicating potential applications of this …


Synthesis And Investigation Of Phthalocyanine-Biotin Conjugates, M. Graca H. Vicente, Elizabeth A. Okoth, Zehua Zhou, Benson Ongarora Jan 2019

Synthesis And Investigation Of Phthalocyanine-Biotin Conjugates, M. Graca H. Vicente, Elizabeth A. Okoth, Zehua Zhou, Benson Ongarora

Faculty Publications

An isothiocyanato-functionalized phthalocyanine (Pc) was synthesized in good yield from the corresponding amine-substituted Pc. This Pc reacted with ethanolamine, biotin hydrazine, and biotin diethylamine under mild conditions (room temperature in DMF or DMSO in the presence of TEA) to produce the corresponding thiourea products in 60-75% yields. All Pcs showed intense Q absorptions in DMF around 677 nm, emissions centered at 683 nm, and fluorescence quantum yields in the range 0.18-0.27. The Pcs were phototoxic to human carcinoma HEp2 cells (IC50 similar to 7 at 1.5 J/cm(2)) and localized in multiple organelles, including the lysosomes, Golgi and ER. One biotin-Pc …