Chemistry Commons^™

Electrocatalytic Performance Of Carbon Supported Ir Catalysts With Different Ir Loadings For Ammonia Oxidation, Yu-Zhi Jiang, Qing-Mei Kong, Tian-Hong Lu, Yi-Ming Zhou, Ya-Wen Tang

Journal of Electrochemistry

The electrocatalytic performance of the Ir/C catalyst as the anodic catalyst in the amperometric and electrochemical NH₃ sensor was investigated.The experimental results illustrated that in the NaClO₄ neutral electrolyte,the electrocatalytic performance of the Ir/C catalyst for the NH₃ oxidation is related to the Ir loading in the Ir/C catalyst.Among the Ir/C catalysts with different Ir loading,the best electrocatalytic activity,stability and sensitivity were achieved by the Ir/C catalyst with 10% Ir loadings.In addition,the current densities of the NH₃ oxidation at the Ir/C catalysts with the different Ir loadings were linearly proportional to the NH₃ concentration.The Ir/C …

Cyclic Voltammetric And In-Situ Ftir Spectroscopic Studies Of Adsorption And Reduction Of No On Electrode Of Pt Nanoparticles, Qian Cheng, Yan-Xia Jiang, Dong-Mei Zeng, Shi-Gang Sun

Journal of Electrochemistry

Adsorption and reduction of NO on electrode of Pt nanoparticles in acid solutions were studied by means of cyclic voltammetry(CV) and in-situ FTIR spectroscopy.The results indicated that the reduction of NO is a complicated process including the adsorption of NO on electrode surface.Two types of surface-bonded NO were determined on Pt nanoparticles.The weakly adsorbed NO was reduced between 0.6 V and-0.05 V,which yielded nitrous oxide(N₂O) and ammonium(NH₄⁺) as products;while the strongly bonded NO was reduced at more negative potentials between-0.05V and-0.15V,producing only NH₄⁺ species.

Synthesis Of α-Mno2 Microspheres For The Application In Supercapacitor, Liang Wang, Gui-Chang Liu, Zhi-Cong Shi

Journal of Electrochemistry

The MnO₂ microspheres were prepared through the oxidation of KMnO₄ and MnCO₃ microspheres precursor.The microstructure and supercapacitor properties of MnO₂ were characterized by XRD,SEM and CV.The results show that MnO₂ was in a poorly crystalline state with α-crystallographic form,the size of microspheres typically ranged from 0.5 to 2 μm.Loading 5 mg·cm^-2 MnO₂ microspheres had excellent capacitance behaviors in 2 mol·L^-1(NH₄)₂SO₄ solution.The specific capacitance was 135.6 F·g^-1 with the scan rate at 2 mV·s^-1,and 118.8 F·g^-1 with the large scan rate at 100 …

Indirect Electrosynthesis Of Double Aldehyde Starch Using Pb-(Bro3-/Br-) As Electro-Catalytic Mediator, Ni-Na Chen, Ri-Yao Chen, Xi Zheng, Xiao Chen, Zhen Chen

Journal of Electrochemistry

In this paper,Nafion membrane was used as the separator in the electrolysis cell to indirectly electro-generating the double aldehyde starch(DAS) with BrO₃^-/Br^-as a redox mediator and Pb as an anode.Effects of temperature,concentration of sulfuric acid and starch on the electro-oxidation of DAS were discussed.The steady state polarization curves were obtained.The experiment results showed that the current efficiency was over 50% when the electrolysis current density was 15mA/ cm².

Preparation And Characterization Of Stable Macroporous Titania Nano-Wells, Hema Santhi Aluri

Theses and Dissertations

Silica based sol-gel thin films have been extensively studied because of their advantages that include optical transparency, high biodegradability and low intrinsic fluorescence. However, one concern with silica based sol-gel derived materials is their long term stability in aqueous solutions. Another concern is their limited porosity. These two concerns limit the application of these materials in catalysis and separations. The main objective of this study is to prepare porous, thin films using titanium alkoxides as precursors and evaluate their long term stability in aqueous solutions. Colloidal crystal templating will be used to introduce macrosized pores into the titania network. The …

Increased Yields And Simplified Purification With A Second-Generation Cobalt Catalyst For The Oxidative Formation Of Trans-Thf Rings., Cory Palmer, Nicholas A Morra, Andrew C Stevens, Barbora Bajtos, Ben P Machin, Brian L Pagenkopf

Chemistry Publications

The synthesis of a second-generation cobalt catalyst for the formation of trans-THF products via the Mukaiyama aerobic oxidative cyclization is reported. Two procedures have been developed with the new water-soluble catalyst that give superior yields and greatly simplify purification compared to the previous catalysts.

Synthesis And Evaluation Of N6,5'-Bis-Ureido-5'-Amino-5'-Deoxyadenosine Derivatives: Novel Nucleosides With Antiproliferative And Protein Kinase Binding Activities, Marcelio Oliveira

Theses and Dissertations

A new series of N6,5'-bis-ureido-5'-amino-5'-deoxyadenosine derivatives was prepared and evaluated for anticancer activities using the NCI 60 panel of human cancers. Certain of the derivatives showed promising activities (low micromolar GI50's) against several of the representative cancers. These included cell lines from the following general cell types in the NCI 60: Leukemia, Breast, Central Nervous System, Non-Small Cell Lung, Ovarian, Prostate, Renal, and Colon cancers. Select compounds were also screened for their affinities for protein kinases. The synthesis of the compounds was straightforward and involved N6 acylation with arylisocyanates, preceded by activation and nucleophilic substitution of the 5'-position to give …

Determination Of 6-Benzylthioinosine In Mouse And Human Plasma By Liquid Chromatography–Tandem Mass Spectrometry, Lan Li, Yan Xu, David N. Wald, William Tse

Chemistry Faculty Publications

This paper described the development and validation of a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the quantitative determination of 6-benzylthioinosine (6BT), a novel myeloid leukemia differentiation-inducing agent, in mouse and human plasma. In this method, 2-amino-6-benzylthioinosine (2A6BT) was used as internal standard and ethyl acetate was used as organic solvent for the extraction of 6BT and internal standard from plasma samples. The extracted samples were separated on YMC ODS-AQ® column (2.0 mm × 50 mm), and the eluates from the column were monitored by the positive-electrospray-ionization tandem mass spectrometer (ESI+-MS/MS). Quantification of 6BT by internal calibration with 2A6BT was …

Inhibitors Of Bacterial N-Succinyl-L,L-Diaminopimelic Acid Desuccinylase (Dape) And Demonstration Of In Vitro Antimicrobial Activity, Danuta Gillner, Nicola Armoush, Richard C. Holz, Daniel P. Becker

Chemistry: Faculty Publications and Other Works

The dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE) is a critical bacterial enzyme for the construction of the bacterial cell wall. A screen biased toward compounds containing zinc-binding groups (ZBG’s) including thiols, carboxylic acids, boronic acids, phosphonates and hydroxamates has delivered a number of micromolar inhibitors of DapE from Haemophilus influenzae, including the low micromolar inhibitor l-captopril (IC50 = 3.3 μM, Ki = 1.8 μM). In vitro antimicrobial activity was demonstrated for l-captopril against Escherichia coli.

Inhibitors Of Bacterial N-Succinyl-L,L-Diaminopimelic Acid Desuccinylase (Dape) And Demonstration Of In Vitro Antimicrobial Activity, Danuta Gillner, Nicola Armoush, Richard C. Holz, Daniel P. Becker

Chemistry Faculty Research and Publications

The dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) is a critical bacterial enzyme for the construction of the bacterial cell wall. A screen biased toward compounds containing zinc-binding groups (ZBG’s) including thiols, carboxylic acids, boronic acids, phosphonates and hydroxamates has delivered a number of micromolar inhibitors of DapE from Haemophilus influenzae, including the low micromolar inhibitor L-captopril (IC₅₀ = 3.3 μM, K_i = 1.8 μM). In vitro antimicrobial activity was demonstrated for l-captopril against Escherichia coli.

Electrochemical And Photovoltaic Properties Of Electropolymerized Poly(Thienyl-Silole)S, Joshua C. Byers, Paul M. Dicarmine, Mahmoud M. A. R. Moustafa, Xin Wang, Brian Pagenkopf, Oleg A. Semenikhin

Chemistry Publications

Electrochemical and photoelectrochemical properties were studied of a series of donor−acceptor materials based on polythiophene modified with silole moieties. The materials were prepared by electrochemical anodic polymerization of 2,5-bis([2,2′-bithiophen]-5-yl)-1,1-dimethyl-3,4-diphenylsilole and 2,5-bis([2,2′-terthiophen]-5-yl)-1,1-dimethyl-3,4-diphenylsilole, as well as copolymerization of these monomers with 2,2′-bithiophene. Photocurrent measurements showed that introduction of silole resulted in a considerable enhancement of the photovoltaic properties of silole-containing materials and especially the fill factor. However, as demonstrated by Mott−Schottky measurements, electropolymerized silole-containing materials showed a substantial degree of disorder and high density of states in the midgap, which negatively affected their photovoltaic properties. Atomic force microscopy (AFM) and phase imaging …

Correlating Molecular Phylogeny With Venom Apparatus Occurrence In Panamic Auger Snails (Terebridae), Mandë Holford, Nicolas Puillandre, Maria Vittoria Modica, Maren Watkins, Rachel Collin, Eldredge Bermingham, Baldomero M. Olivera

Publications and Research

Central to the discovery of neuroactive compounds produced by predatory marine snails of the superfamily Conoidea (cone snails, terebrids, and turrids) is identifying those species with a venom apparatus. Previous analyses of western Pacific terebrid specimens has shown that some Terebridae groups have secondarily lost their venom apparatus. In order to efficiently characterize terebrid toxins, it is essential to devise a key for identifying which species have a venom apparatus. The findings presented here integrate molecular phylogeny and the evolution of character traits to infer the presence or absence of the venom apparatus in the Terebridae. Using a combined dataset …

Investigation Of The Physical And Electronic Properties Of Indium Doped Zinc Oxide Nanofibers Synthesized By Electrospinning, A. F. Lotus, Y. C. Kang, R. D. Ramsier, George G. Chase

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Nanostructured metal oxides and particularly nanofiber based materials can provide significant advances for the miniaturization of electronic, optoelectronic, photonic, sensor, and energy conversion devices with enhanced performance based on their unique material properties. In this study, indium doped zinc oxide (IZO) nanofibers were synthesized by electrospinning. These nanofibers have diameters in the range 50-100 nm. The effects of indium addition on the structural, optical, and electrical properties of the zinc oxide nanofiber matrices were investigated. The IZO nanofibers undergo significant changes in their optical and electrical properties compared to undoped zinc oxide nanofibers.

Analysis Of Globule Types In Malignant Melanoma, Jin Xu, Kapil Kumar Gupta, William V. Stoecker, Yamini Krishnamurthy, Harold S. Rabinovitz, Austin Bangert, David A. Calcara, Margaret C. Oliviero, Joseph M. Malters, Rhett J. Drugge, R. Joe Stanley, Randy Hays Moss, Mehmed Emre Celebi

Chemistry Faculty Research & Creative Works

Objective: To identify and analyze subtypes of globules based on size, shape, network connectedness, pigmentation, and distribution to determine which globule types and globule distributions are most frequently associated with a diagnosis of malignant melanoma. Design: Retrospective case series of dermoscopy images with globules. Setting: Private dermatology practices. Participants: Patients in dermatology practices. Intervention: Observation only. Main Outcome Measure: Association of globule types with malignant melanoma. Results: The presence of large globules (odds ratio [OR], 5.25) and globules varying in size (4.72) or shape (5.37) had the highest ORs for malignant melanoma among all globule types and combinations studied. Classical …

Synthesis And Evaluation Of Some Steroidal Oximes As Cytotoxic Agents: Structure/Activity Studies (Ii), Jianguo Cui, Lei Fan, Yanmin Huang, Yi Xin, Aimin Zhou

Chemistry Faculty Publications

Hydroximinosteroids isolated from marine sponges display a variety of biological functions including cytotoxicity and anti-virus. In this study, we synthesized a series of hydroximinosteroid derivatives with a different functional group on the ring A or B and various side chains at position 17, and analyzed the cytotoxicity of these compounds against sk-Hep-1, H-292, PC-3 and Hey-1B cancer cells. Our results revealed that although a cholesterol-type side chain at position 17 is required for the biological activity of the compounds as we previously confirmed, elimination of the 4,5-double bond augmented the cytotoxic activity for the steroidal oximes. In addition, the presence …

How Does The Relocation Of Internal Water Affect Resonance Raman Spectra Of Rhodopsin? An Insight From Casscf/Amber Calculations, Tadeusz Andruniow, Massimo Olivucci

Chemistry Faculty Publications

The effect of relocation of the W2 crystallographic water in bovine rhodopsin has been investigated by comparing and analyzing simulated resonance Raman spectra of I HZX-and 1U19-based quantum mechanics/molecular mechanics (CASSCF/MM) models. The main target is to explore the sensitivity of the simulated resonance Raman spectra to protein cavity change. In particular, we focus on a quantitative investigation of the changes in the vibrational activity of rhodopsin induced by modifications in the protein cavity structure and in the water position. Comparison of the simulated FIR spectra of the Rh-1U19 and Rh-1HZX models with the measured spectrum of rhodopsin reveals that …

Improving Replica Exchange Using Driven Scaling, Steven W. Rick

Chemistry Faculty Publications

Replica exchange is a powerful simulation method in which simulations are run at a series of temperatures, with the highest temperature chosen so phase space can be sampled efficiently. In order for swaps to be accepted, the energy distributions of adjacent replicas must have some overlap. This can create the need for many replicas for large systems. In this paper, we present a new method in which the potential energy is scaled by a parameter, which has an explicit time dependence. Scaling the potential energy broadens the distribution of energy and reduces the number of replicas necessary to span a …

Fragmentation Properties Of Three-Membered Ring Heterocyclic Molecules By Partial Ion Yield Spectroscopy: C2h4o And C2h4s, Wayne C. Stolte, I. Dumitriu, S-W Yu, Gunnar Ohrwall, Maria Novella Piancastelli, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

We investigated the photofragmentation properties of two three-membered ring heterocyclic molecules, C₂H₄O and C₂H₄S, by total and partial ion yield spectroscopy. Positive and negative ions have been collected as a function of photon energy around the C 1s and O 1s ionization thresholds in C₂H₄O, and around the S 2p and C 1s thresholds in C₂H₄S. We underline similarities and differences between these two analogous systems. We present a new assignment of the spectral features around the C K-edge and the sulfur L_{2 …}

Smooth Potential Energy Surface For Cavitation, Dispersion, And Repulsion Free Energies In Polarizable Continuum Model, Yali Wang, Hui Li

Hui Li Publications

The fixed points with variable areas [FIXPVA] tessellation scheme is used to obtain smooth potential energy surfaces for the cavitation G_cav, dispersion G_dis, and repulsion G_rep free energies in the polarizable continuum model (PCM). It is shown that FIXPVA can reproduce the standard GEPOL results to within 1 kcal/mol.

Polymer Nanocomposites Using Zinc Aluminum And Magnesium Aluminum Oleate Layered Double Hydroxides: Effects Of The Polymeric Compatibilizer And Of Composition On The Thermal And Fire Properties Of Pp/Ldh Nanocomposites, Charles Manzi-Nshuti, Ponusa Songtipya, Evangelos Manias, Maria Del Mar Jimenez-Gasco, Jeanne Hossenlopp, Charles A. Wilkie

Chemistry Faculty Research and Publications

A series of five oleate-containing layered double hydroxides with varied ratios of zinc to magnesium, i.e., with the general formula Zn_2−yMg_yAl(OH)₆ [CH₃(CH₂)₇CHCH(CH₂)₇COO]·nH₂O, were synthesized and used to prepare nanocomposites of polypropylene (PP). The nanomaterials were characterized by elemental analysis, attenuated total reflection-infrared spectroscopy (ATR-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), while the composites were characterized by XRD, TGA, transmission electron microscopy (TEM) and cone calorimetry. The zinc-containing LDH showed better dispersion in the polymer at the micrometer level …

The Effects Of Intralayer Metal Composition Of Layered Double Hydroxides On Glass Transition, Dispersion, Thermal And Fire Properties Of Their Pmma Nanocomposites, Charles Manzi-Nshuti, Dan Chen, Shengpei Su, Charles A. Wilkie

Chemistry Faculty Research and Publications

A series of aluminum-containing layered double hydroxides (LDHs), containing Mg, Ca, Co, Ni, Cu and Zn as the divalent metals, have been prepared by the co-precipitation method and used to prepare nanocomposites of PMMA by in situ bulk polymerization. The additives were characterized by Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy (XRD) and thermogravimetric analysis while the polymer composites were characterized by XRD, transmission electron microscopy, differential scanning calorimetry and cone calorimetry. Polymerization of methyl methacrylate in the presence of these undecenoate LDHs results in composites with enhanced thermal stability. The glass transition temperatures of the composites and the pristine …

Scope And Mechanistic Investigations On The Solvent-Controlled Regio- And Stereoselective Formation Of Enol Esters From The Ruthenium-Catalyzed Coupling Reaction Of Terminal Alkynes And Carboxylic Acids, Chae S. Yi, Ruili Gao

Chemistry Faculty Research and Publications

The ruthenium-hydride complex (PCy₃)₂(CO)RuHCl was found to be a highly effective catalyst for the alkyne-to-carboxylic acid coupling reaction to give synthetically useful enol ester products. A strong solvent effect was observed for the ruthenium catalyst in modulating the activity and selectivity; the coupling reaction in CH₂Cl₂ led to the regioselective formation of gem-enol ester products, while the stereoselective formation of (Z)-enol esters was obtained in THF. The coupling reaction was found to be strongly inhibited by PCy₃. The coupling reaction of both PhCO₂H/PhC≡CD and PhCO_{2 …}

A General Asymmetric Aldol Reaction Of Silyl Ketene Acetals Derived From Simple Esters To Aryl Alpha-Ketoesters, Brian Pagenkopf, Julie Le Engers

Chemistry Publications

No abstract provided.

Wavepacket Approach To The Cumulative Reaction Probability Within The Flux Operator Formalism, Sophya Garashchuk, Tijo Vazhappilly

Faculty Publications

Expressions for the singular flux operator eigenfunctions and eigenvalues are given in terms of the Dirac δ-function representable as a localized Gaussian wavepacket. This functional form enables computation of the cumulative reaction probability N(E) from the wavepacket time-correlation functions. The Gaussian based form of the flux eigenfunctions, which is not tied to a finite basis of a quantum-mechanical calculation, is particularly useful for approximate calculation of N(E) with the trajectory based wavepacket propagation techniques. Numerical illustration is given for the Eckart barrier using the conventional quantum-mechanical propagation and the quantum trajectory dynamics with the approximate quantum potential. N(E) converges with …

Chemistry In Second Life, Andrew Lang, Jean-Claude Bradley

College of Science and Engineering Faculty Research and Scholarship

This review will focus on the current level on chemistry research, education, and visualization possible within the multi-user virtual environment of Second Life. We discuss how Second Life has been used as a platform for the interactive and collaborative visualization of data from molecules and proteins to spectra and experimental data. We then review how these visualizations can be scripted for immersive educational activities and real-life collaborative research. We also discuss the benefits of the social networking affordances of Second Life for both chemists and chemistry students.

Magnetoelastic Coupling Through The Antiferromagnet-To-Ferromagnet Transition Of Quasi-Two-Dimensional [Cu(Hf2)(Pyz)(2)]Bf4 Using Infrared Spectroscopy, J L. Musfeldt, L I. Vergara, T V. Brinzari, C Lee, L C. Tung, J Kang, Y J. Wang, J A. Schlueter, Jamie L. Manson, M H. Whangbo

Chemistry and Biochemistry Faculty Publications

We investigated magnetoelastic coupling through the field-driven transition to the fully polarized magnetic state in quasi-two-dimensional [Cu(HF2)(pyz)(2)]BF4 by magnetoinfrared spectroscopy. This transition modifies out-of-plane ring distortion and bending vibrational modes of the pyrazine ligand. The extent of these distortions increases with the field, systematically tracking the low-temperature magnetization. These distortions weaken the antiferromagnetic spin exchange, a finding that provides important insight into magnetic transitions in other copper halides.

Depositional Ice Nucleation On Solid Ammonium Sulfate And Glutaric Acid Particles, K. J. Baustian, M. E. Wise, M. A. Tolbert

CUP Faculty Research

Heterogeneous ice nucleation on solid ammonium sulfate and solid amorphous glutaric acid particles was studied using optical microscopy and Raman spectroscopy. Optical microscopy was used to detect selective nucleation events as water vapor was slowly introduced into an environmental sample cell. Particles that nucleated ice were dried via sublimation and examined in detail using Raman spectroscopy. Depositional ice nucleation occurred preferentially on just a few ammonium sulfate and glutaric acid particles in each sample. For freezing temperatures between 214 K and 235K average ice saturation ratios of S=1.10±0.07 for solid ammonium sulfate and S=1.39±0.16 for solid amorphous glutaric …

Reexamine Structures And Relative Stability Of Medium-Sized Silicon Clusters: Low-Lying Endohedral Fullerene-Like Clusters Si30-Si38, Soohaeng Yoo, Nan Shao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We report improved results of lowest-lying silicon clusters Si₃₁–Si₃₈. A large population of low-energy clusters are collected from previous searches by several research groups and the binding energies of these clusters are computed using density-functional theory (DFT) methods. Best candidates (isomers with high binding energies) are identified from the screening calculations. Additional constrained search is then performed for the best candidates using the basin-hopping method combined with DFT geometry optimization. The obtained low-lying clusters are classified according to binding energies computed using either the Perdew–Burke–Ernzerhof (PBE) functional or the Becke exchange and Lee–Yang–Parr correlation (BLYP) functional. …

Robust Quantization Of A Molecular Motor Motion In A Stochastic Environment, Vladimir Y. Chernyak, Nikolai A. Sinitsyn

Chemistry Faculty Research Publications

We explore quantization of the response of a molecular motor to periodic modulation of control parameters. We formulate the pumping-quantization theorem (PQT) that identifies the conditions for robust integer quantized behavior of a periodically driven molecular machine. Implication of PQT on experiments with catenane molecules are discussed. ACKNOWLEDGMENTS We are grateful to M. Chertkov, J. R. Klein, and J. Horowitz for useful discussions. This material is based upon work supported by NSF under Grant Nos. CHE-0808910 and ECCS-0925618.

Chemistry & Biochemistry Newsletter, Department Of Chemistry & Biochemistry, South Dakota State University

Chemistry & Biochemistry Newsletter: 2002-2015

Inside:

Page 2 Research Finds New Uses for Light or Applied Photonics

Page 3 SDSU Grad Student Awarded EPA Sustainability Grant; Alumni Update

Page 4 New CLS Faculty

Page 5 Chemistry: It’s Elemental; Alumni Update

Page 6-7 New Graduate Students

Page 7 AHSC Construction Update

Page 8 Rice Named to National Science Foundation Committee