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Organic Chemistry Commons™

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2014

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Articles 91 - 100 of 100

Full-Text Articles in Organic Chemistry

The Synthesis Of A Bisbenzothiophene (Bbt) Based Organic Semiconductor With Increased Function And Increased Solubility, Mary England Jan 2014

The Synthesis Of A Bisbenzothiophene (Bbt) Based Organic Semiconductor With Increased Function And Increased Solubility, Mary England

Senior Honors Theses

Organic semiconductors are growing in applications for use in modern technology.1 The main interest in these molecules can be attributed to their low cost (compared to silicon) and their ability to be used on flexible substrates. There are four features that make a good organic semiconductor. First, the molecule should be conjugated, having alternating single and double bonds (lone electron pairs act similarly to double bonds). Secondly, the molecule should be planar, or flat, in shape. Thirdly, the molecule should have a narrow band gap to increase the overall conductivity. Lastly, the molecule should be soluble to ease application. …

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Synthesis And Characterization Of Fluorophores For The Detection Of Lanthanides And Actinides, Robinson I. Roacho Jan 2014

Synthesis And Characterization Of Fluorophores For The Detection Of Lanthanides And Actinides, Robinson I. Roacho

Open Access Theses & Dissertations

A series of fluorophores based in the boron dipyrromethene (BODIPY) family were synthesized and characterized. These fluorophores have the capacity of being introduced to a carbamoyl methyl phosphine oxide (CMPO) lanthanide/actinide extractant. These blue, green and red emission fluorophores show high thermal/moisture stability and high fluorescence efficiencies. The fluorescence intensity seems to be dependent on the restricted rotation about the C(8)-C bond in 8-Ph-BODIPY. By taking advantage of this feature, a hydroxyl- containing BODIPY with high fluorescence intensity was synthesized to be incorporated to a CMPO carboxylic acid via esterification. Unfortunately, we did not observe an optical response upon the …

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Isomerase Activity Of Candida Rugosa Lipase In Conversion Of Racemic Ibuprofen To (S)-Ibuprofen, Saideh Sadat Mortazavi Jan 2014

Isomerase Activity Of Candida Rugosa Lipase In Conversion Of Racemic Ibuprofen To (S)-Ibuprofen, Saideh Sadat Mortazavi

Open Access Theses & Dissertations

The Candida rugosa lipase-catalyzed Dynamic Kinetic Resolution of racemic ibuprofen methyl ester was optimal at pH 7.6 to produce (S)-ibuprofen in 72 hours. The concentration of various buffers for these reactions ranged from 0.2 to 0.5 M. The commercial lipase was found to be acidic altering the final pH of the reaction mixtures. Dimethylformamide co-solvent maintained the reaction pH better than dimethylsulfoxide, with evidence of the latter functioning as an oxidizing agent. Lower concentrations of ibuprofen methyl ester and higher stirring rates led to faster conversions. The minimal amount of lipase needed was 20 mg/mL buffer. Reaction of (R)-ibuprofen methyl …

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Visible Light Mediated Intermolecular [3 + 2] Annulation Of Cyclopropylanilines With Alkynes, Theresa H. Nguyen, Soumitra Maity, Nan Zheng Jan 2014

Visible Light Mediated Intermolecular [3 + 2] Annulation Of Cyclopropylanilines With Alkynes, Theresa H. Nguyen, Soumitra Maity, Nan Zheng

Chemistry & Biochemistry Faculty Publications and Presentations

Intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes is realized using visible light photoredox catalysis, yielding a variety of cyclic allylic amines in fair to good yields. This method exhibits significant group tolerance particularly with heterocycles. It can also be used to prepare complex heterocycles such as fused indolines.

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Visible-Light Photocatalyzed Cross-Linking Of Diacetylene Ligands By Quantum Dots To Improve Their Aqueous Colloidal Stability, Marion G. Götz, Hiroko Takeuchi, Matthew J. Goldfogel, Julia M. Warren, Brandon D. Fennel, Colin D. Heyes Jan 2014

Visible-Light Photocatalyzed Cross-Linking Of Diacetylene Ligands By Quantum Dots To Improve Their Aqueous Colloidal Stability, Marion G. Götz, Hiroko Takeuchi, Matthew J. Goldfogel, Julia M. Warren, Brandon D. Fennel, Colin D. Heyes

Chemistry & Biochemistry Faculty Publications and Presentations

Ligand cross-linking is known to improve the colloidal stability of nanoparticles, particularly in aqueous solutions. However, most cross-linking is performed chemically, in which it is difficult to limit interparticle cross-linking, unless performed at low concentrations. Photochemical cross-linking is a promising approach but usually requires ultraviolet (UV) light to initiate. Using such high-energy photons can be harmful to systems in which the ligand–nanoparticle bond is fairly weak, as is the case for the commonly used semiconductor quantum dots (QDs). Here, we introduce a novel approach to cross-link thiolated ligands on QDs by utilizing the photocatalytic activity of QDs upon absorbing visible …

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Evaluating N-Benzylgalactonoamidines As Putative Transition State Analogs For Β-Galactoside Hydrolysis, Qui-Hua Fan, Susanne Striegler, Rebekah Langston, James Barnett Jan 2014

Evaluating N-Benzylgalactonoamidines As Putative Transition State Analogs For Β-Galactoside Hydrolysis, Qui-Hua Fan, Susanne Striegler, Rebekah Langston, James Barnett

Chemistry & Biochemistry Faculty Publications and Presentations

Experimental evidence is provided for p-methylbenzyl-D-galactonoamidine to function as a true transition state analog for the enzymatic hydrolysis of aryl-β-D-galactopyranosides by β-galactosidase (A. oryzae). The compound exhibits inhibition constants in the low nanomolar concentration range (12–56 nM) for a selection of substrates. Along these lines, a streamlined synthetic method based on phase-transfer catalysis was optimized to afford the required variety of new aryl-β-D-galactopyranosides. Last, the stability of the galactonoamidines under the assay conditions was confirmed.

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Investigations Towards Synthesis Of Cinnamaldehyde Semicarbazone Derivatives And Their Photochromicity By Modifying The Ring, The Linker, And The Semicarbazone, Xiao Xiao Jan 2014

Investigations Towards Synthesis Of Cinnamaldehyde Semicarbazone Derivatives And Their Photochromicity By Modifying The Ring, The Linker, And The Semicarbazone, Xiao Xiao

Masters Theses

Cinnamaldehyde semicarbazone was varied in three ways, by altering the ring, the conjugated linker, and the semicarbazone, to investigate how changing the structure affects the photochomicity. The synthesis of 7 hetero- and 2 polycyclic- aromatic semicarbazone variants involved three steps, (a Wittig reaction, hydrolysis, and condensation to the semicarbazone) with cumulative yields of 15% to 52%. Generally, the pyridine series gave lower yields than other synthesized semicarbazones. The Wittig reaction gave cis/trans mixtures in ratios of 2 : 1 to 1 : 7 for the 6 acetals, except for the 3 that went directly to the aldehyde, due to the …

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Electrode And Electrolyte Additives For Lifetime Extension In Lithium-Ion Batteries, Kishore Anand Narayana Jan 2014

Electrode And Electrolyte Additives For Lifetime Extension In Lithium-Ion Batteries, Kishore Anand Narayana

Theses and Dissertations--Chemistry

Lithium-ion batteries (LIBs) are the most commonly used type of rechargeable batteries with a global market estimated at $11 billion, which is predicted to grow to $60 billion by 2020. The global commercialization of Li-ion batteries is impeded by issues such as poor cycle life (5000 cycles achieved in some LIBs) in high energy and power density applications because of the rising internal resistance due to aging and safety concerns such as overcharge which ultimately leads to thermal runaway and explosions. A battery’s performance mainly depends on external factors such as electrode thickness and degree of compacting, and the type …

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Investigations Into The Fluorescent Covalent Labeling Of Biomolecules Utilizing Rhodamine Dyes, Electrophilic Leaving Groups And Mrna Display., Susan D. Selaya Jan 2014

Investigations Into The Fluorescent Covalent Labeling Of Biomolecules Utilizing Rhodamine Dyes, Electrophilic Leaving Groups And Mrna Display., Susan D. Selaya

Theses and Dissertations

The discovery of a method by which proteins of interest can selectively be labeled with a probe of choice intracellularly is a longstanding goal in chemical biology research. Conventional labeling techniques have utilized large domain tags but despite the development of small labeling molecules there have been no short peptide sequences known to covalently label a small molecule without the aid of an enzymatic process or metal chelation. We aimed to find a sequence of nucleophilic peptides that reacted covalently and specifically with electrophilic small labeling molecules using mRNA display. Our goal was to show that an electrophilic small labeling …

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Probing The Human Estrogen Receptor-Α Binding Requirements For Phenolic Mono- And Di-Hydroxyl Compounds: A Combined Synthesis, Binding And Docking Study, Christopher Mccullough, Terrence S. Neumann, Jayapal Reddy Gone, Zhengjie He, Christian Herrild, Julie Lukesh, Rajesh K. Pandey, William A. Donaldson, Daniel S. Sem Jan 2014

Probing The Human Estrogen Receptor-Α Binding Requirements For Phenolic Mono- And Di-Hydroxyl Compounds: A Combined Synthesis, Binding And Docking Study, Christopher Mccullough, Terrence S. Neumann, Jayapal Reddy Gone, Zhengjie He, Christian Herrild, Julie Lukesh, Rajesh K. Pandey, William A. Donaldson, Daniel S. Sem

Chemistry Faculty Research and Publications

Various estrogen analogs were synthesized and tested for binding to human ERα using a fluorescence polarization displacement assay. Binding affinity and orientation were also predicted using docking calculations. Docking was able to accurately predict relative binding affinity and orientation for estradiol, but only if a tightly bound water molecule bridging Arg394/Glu353 is present. Di-hydroxyl compounds sometimes bind in two orientations, which are flipped in terms of relative positioning of their hydroxyl groups. Di-hydroxyl compounds were predicted to bind with their aliphatic hydroxyl group interacting with His524 in ERα. One nonsteroid-based dihdroxyl compound was 1000-fold specific for ERβ over ERα, and …

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