Chemistry Commons^™

Optimization Of Microwave-Assisted Acid Digestion Method For Determination Of Trace Elements In Coal And Coal Fly Ash, Dejan Savic

Masters Theses & Specialist Projects

In most of the analytical and environmental laboratories today inductively coupled plasma (ICP) is a method of choice for analysis of trace metal elements present in coal and coal combustion products. This method requires use of liquid samples, so all coal and coal combustion products must be digested prior to analysis by ICP. Traditionally an open-air hot-plate acid digestion method published as ASTM D6357-04 was used to extract all trace metal elements into solution.

Recent development of microwave systems designed for digestions under extreme acidic conditions and high temperatures and pressures shifted focus toward more rapid and precise microwave-assisted digestion …

Department Of Chemistry News For Alumni And Friends, July 2008, Illinois State University, Department Of Chemistry

Chem Letter

Newsletter of the Illinois State University Department of Chemistry

Chiral Recognition And Binding Constant Determination In Monovalent And Bivalent Systems Using Electrospray Ionization Mass Spectrometry, Manishkumar Joshi

Chemistry & Biochemistry Theses - Archive

Electrospray ionization mass spectrometry (ESI-MS) is a soft ionization method which is capable of transferring weakly bound host-guest noncovalent complexes from the solution phase to the gas phase. This capability makes ESI-MS an ideal tool for the quantification of binding affinities of different host-guest noncovalent complexes. There is a growing interest in using ESI-MS for chiral recognition studies. In thiswork ESI-MS was employed to investiga te the binding affinities for cinchona alkaloid chiral selectors binding N-blocked leucine enantiomers, as well as for macrocyclic antibiotics binding a variety of derivatized and underivatized amino acids. The effect of multivalency on binding affinity …

Seminaphthofluorones Are A Family Of Water-Soluble, Low Molecular Weight, Nir-Emitting Fluorophores, Youjun Yang, Mark Lowry, Xiangyang Xu, Jorge O. Escobedo, Martha Sibrian-Vazquez, Lisa Wong, Corin M. Schowalter, Timothy J. Jensen, Frank R. Fronczek, Isiah M. Warner, Robert M. Strongin

Chemistry Faculty Publications and Presentations

A readily accessible new class of near infrared (NIR) molecular probes has been synthesized and evaluated. Specific fluorophores in this unique xanthene based regioisomeric seminaphthofluorone dye series exhibit a combination of desirable characteristics including (i) low molecular weight (339 amu), (ii) aqueous solubility, and (iii) dual excitation and emission from their fluorescent neutral and anionic forms. Importantly, systematic changes in the regiochemistry of benzannulation and the ionizable moieties afford (iv) tunable deep-red to NIR emission from anionic species and (v) enhanced Stokes shifts. Anionic SNAFR-6, exhibiting an unusually large Stokes …

Poly(Ethylenedioxythiophene) Based Electronic Devices For Sensor Applications, Jie Liu

Doctoral Dissertations

Organic electronic devices, based on Poly (3,4-ethylenedioxythiophene)-Poly (styrene sulfonic acid) (PEDOT-PSS) as the active layer for sensor applications, have been studied. Two sets of sensors have been developed. In one case, sensors consisting of PEDOT-PSS resistors have been realized and demonstrated for soil moisture monitoring. The resistor model for the soil moisture sensor enables the sensor device to be fabricated at low cost and easily tested with a simple structure. Unlike the large dimension device used in Time Domain Reflectometry (TDR), the sensors are small and are capable of capturing microscale behavior of moisture in soil which is useful for …

Electron Crystallography Of Aquaporins, Simeon Andrews, Steve Reichow, Tamir Gonen

Chemistry Faculty Publications and Presentations

Aquaporins are a family of ubiquitous membrane proteins that form a pore for the permeation of water. Both electron and X-ray crystallography played major roles in determining the atomic structures of a number of aquaporins. This review focuses on electron crystallography, and its contribution to the field of aquaporin biology. We briefly discuss electron crystallography and the two-dimensional crystallization process. We describe features of aquaporins common to both electron and X-ray crystallographic structures; as well as some structural insights unique to electron crystallography, including aquaporin junction formation and lipid-protein interactions.

Β-Diketonate, Β-Ketoiminate, And Β-Diiminate Complexes Of Difluoroboron, Felipe P. Macedo, Chengeto Gwengo, Sergey V. Lindeman, Mark D. Smith, James R. Gardinier

Chemistry Faculty Research and Publications

A series of β-diketonate, keto(aryl)iminato, and β-bis(aryl)iminato complexes of difluoroboron, twenty in total, have been prepared to assess the impact of chelate ring and aniline substitution on the structural, electrochemical, and photophysical properties of these ubiquitous chelates. DFT (B3LYP/6-31G*) calculations supplemented the experimental results and both demonstrated that replacing oxygen with the more electron-donating aniline groups serves to only fine-tune the electronic properties because both the HOMO and LUMO energies are affected by such substitution. The electronic properties of all compounds are most greatly influenced by the nature of the substituents bound to the carbon portion of the chelate ring. …

The Role Of Upstream Sequences In Selecting The Reading Frame On Tmrna, Allen R. Buskirk, Mickey R. Miller, David W. Healey, Jonathan D. Dewey, Stephen G. Robison

Faculty Publications

tmRNA acts first as a tRNA and then as an mRNA to rescue stalled ribosomes in eubacteria. Two unanswered questions about tmRNA function remain: how does tmRNA, lacking an anticodon, bypass the decoding machinery and enter the ribosome? Secondly, how does the ribosome choose the proper codon to resume translation on tmRNA? According to the -1 triplet hypothesis, the answer to both questions lies in the unique properties of the three nucleotides upstream of the first tmRNA codon. These nucleotides assume an A-form conformation that mimics the codon-anticodon interaction, leading to recognition by the decoding center and choice of the …

Manipulating The Cavity Of A Porous Material Changes The Photoreactivity Of Included Guests, Mahender B. Dewal, Yuewen Xu, Jun Yang, Fiaz Mohammed, Mark D. Smith, Linda S. Shimizu

Faculty Publications

Changing an ether to a ketone within the framework of a bis-urea macrocycle has little effect on the supramolecular assembly of this building block into porous crystals but introduces a triplet sensitizer into the framework that dramatically alters the photochemical reactions of included guests.

Quantitative Measure Of Cytotoxicity Of Anticancer Drugs And Other Agents., Zhimin Tao, Eyone Jones, Jerry Goodisman, Abdul-Kader Souid

Chemistry - All Scholarship

Many anticancer drugs act on cancer cells to promote apoptosis, which includes impairment of cellular respiration (mitochondrial O(2) consumption). Other agents also inhibit cellular respiration, sometimes irreversibly. To investigate the sensitivity of cancer cells to cytotoxins, including anticancer drugs, we compare the profiles of cellular O(2) consumption in the absence and presence of these agents. Oxygen measurements are made at 37 degrees C, using glucose as a substrate, with [O(2)] obtained from the phosphorescence decay rate of a palladium phosphor. The rate of respiration k is defined as -d[O(2)]/dt in a sealed container. Different toxins produce different profiles of impaired …

Silylethynylated Heteroacenes And Electronic Devices Made Therewith, John E. Anthony, Marcia M. Payne, Susan A. Odom, Sean Parkin

Chemistry Faculty Patents

Novel silylethynylated heteroacenes and electronic devices made with those compounds are disclosed.

Working Report On The Status Quo Of Nanomaterials Impact On Health And Environment, Harald Krug, Margarita Apostolova, Marite Arija Bake, Gordon Chambers, Horia Chiriac, Eva Herzog, Victoria Hand, Jürgen Höck, Peter Hoet, Nicoleta Lupu, Declan Mccormack, Maja Remskar, George Robillard, Jamila Smisterova, Jan Stetkiewicz, Speranta Tanasescu, Aris Tsatsakis, David Vaughn, Peter Wick, Jörg Wörle-Knirsch

Articles

Nanotechnology is regarded as one of the key technologies of the future and associated with high expectations by politics, science and economy. Artificially produced nanosized particles and nanoscale system components have new properties which are of importance for the development of new products and applications. Such new properties of materials and substances result from the special properties of surfaces and interfaces and in part, from the geometric shape of the material. In theory nanoparticles (NPs) can be produced from nearly any chemical; however, most NPs that are currently in use today have been made from transition metals, silicon, carbon (single-walled …

Development And Investigation Of Unique Organic Materials To Detect Disease Biomarkers, George Kiplimo Samoei

Dissertations and Theses

Chemomechanical polymer gels with the capability of recognizing specific biological molecules are promising materials for many biomedical applications. Glucose-selective hydrogels have potential utility in the continuous monitoring of glucose and glucose-triggered insulin delivery for the management of diabetes. Herein, the development and study of the first material which detects glucose via significant volume changes in the challenging matrix human blood plasma is described. The material was created via the modification of PMMA with supramolecular binding sites. The polymer exhibits excellent selectivity and reversibility including continuous expansion-contraction cycles.

Anisotropy Of Crystal-Melt Interfacial Free Energy Of Silicon By Simulation, Pankaj A. Apte, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We extend the cleaving wall method to a nonpairwise additive potential. Using this method, we compute the anisotropy of crystal-melt interfacial free energy γ for Stillinger–Weber potential of silicon [F. H. Stillinger and T. A. Weber, Phys. Rev. B 31, 5262 (1985)]. The calculated γ for (100), (111), and (110) orientations are 0.42±0.02, 0.34±0.02, and 0.35±0.03 J &#;m², respectively. The anisotropy in γ we found is consistent with the experimental observation that Si(100)-melt interface develops (111) facets and also helps in explaining a higher undercooling observed for Si(111)-melt interface in Czochralski method.

The Role Of The Tight-Turn, Broken Hydrogen Bonding, Glu222 And Arg96 In The Post-Translational Green Fluorescent Protein Chromophore Formation, Marc Zimmer, Nathan P. Lemay, Alicia L. Morgan, Elizabeth J. Archer, Luisa A. Dickson, Colleen M. Megley

Chemistry Faculty Publications

Green fluorescent proteins (GFP) and GFP-like proteins all undergo an autocatalytic post-translational modification to form a centrally located chromophore. Structural analyses of all the GFP and GFP-like proteins in the protein databank were undertaken to determine the role of the tight-turn, broken hydrogen bonding, Gly67, Glu222 and Arg96 in the biosynthesis of the imidazolone group from 65SYG67. The analysis was supplemented by computational generation of the conformation adopted by uncyclized wild-type GFP. The data analysis suggests that Arg96 interacts with the Tyr66 carbonyl, stabilizing the reduced enolate intermediate that is required for cyclization; the carboxylate of Glu222 acts as a …

Cd2+-Induced Conformational Change Of A Synthetic Metallopeptide: Slow Metal Binding Followed By A Slower Conformational Change, Madhumita Mukherjee, Xianchun Zhu, Michael Y. Ogawa

Chemistry Faculty Publications

A two-stranded a-helical coiled coil was prepared having a Cys(4) metal-binding site within its hydrophobic interior. The addition of Cd2+ results in the incorporation of 2 equiv of metal ion, which is accompanied by a conformational change of the peptide, as observed by circular dichroism (CID) spectroscopy. Isothermal titration calorimetry (ITC) shows that the addition of Cd2+ is accompanied by two thermodynamic events. A comparison of the time dependence of the ITC behavior with those of the UV absorption and CID behavior allows the assignment of these events to a preliminary endothermic metal-binding step followed by a slower exothermic conformational …

Origin Of The Absorption Maxima Of The Photoactive Yellow Protein Resolved Via Ab Initio Multiconfigurational Methods, Pedro B. Coto, Sergio Martí, Monica Oliva, Massimo Olivucci, Manuela Merchan, Juan Andre

Chemistry Faculty Publications

We discuss the role of the protein in controlling the absorption spectra of photoactive yellow protein (PYP), the archetype xanthopsin photoreceptor, using quantum mechanics/molecular mechanics (QM/MM) methods based on ab initio multireference perturbation theory, combined with molecular dynamics (MD) simulations. It is shown that in order to get results in agreement with the experimental data, it is necessary to use a model that allows for a proper relaxation of the whole system and treats the states involved in the electronic spectrum in a balanced way, avoiding biased results due to the effect of nonrepresentative electrostatic interactions on the chromophore.

Spectroscopy Is Applied Quantum Mechanics. Part 4: Ideal Systems, David W. Ball

Chemistry Faculty Publications

The article features the last and fourth part of the lecture series about the application of quantum mechanics to spectroscopy. It examines ideal systems with wave functions that can be derived from the Schroedinger equation. It likewise follows discourse for failings of classical mechanics, the quantum hypothesis, and the emergence of a new theory called quantum mechanics.

Medium-Sized Double Magic Metal Clusters: Al@Cu54- And Al@Ag54-, Yi Gao, Nan Shao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Medium-sized double magic metal clusters, Al@Ag₅₄^- and Al@₅₄^-, are predicted based on unbiased global search and density functional calculation. Both bimetallic core-shell clusters have icosahedral symmetry, and they are much lower in energies than all other low-lying isomers. In contrast, the icosahedral cluster Al@₅₄^- is a high-energy isomer. Both Al@₅₄^- and Al@Cu₅₄^- exhibit appreciable gaps between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, and strong spherical aromaticity, which provide two additional evidences for the likelihood of their high stability. The simulated anion photoelectron spectra and …

Synthesis, Characterization, And Catalytic Application Of Gold Nanoparticles, Junhyung Kim

Dissertations

Properties of nanometer-sized gold(Au) particles, especially those that are protected by a monolayer coating of thiolate ligands, called 'Monolayer Protected Clusters' (MPCs), are of rigorous multidisciplinary interest for their potential applications in catalysis and electronics due to their variation with size.

In larger core diameter sizes (>1.5nm) AuMPCs show metallic behavior as observed from electrochemical measurements. On the other hand, sub-nanometer ([approximate]1.1nm) AuMPCs exhibit molecule-like electronic behavior which is typical of Au38 nanoparticles. The various alkane chain thiols(C4 S-C12 S) capped Au38 MPCs have been examined with independent analytical tools, producing a remarkably consistent picture of these materials.

The …

Exploration Of The Chemical And Biological Processes Through Molecular Dynamics Simulation And Blocklocalized Wavefunction Method, Yuchun Lin

Dissertations

Computer simulation plays a crucial role in interpreting, unifying and guiding experimental observations. In this dissertation, molecular dynamics (MD) simulations and the block-localized wavefunction (BLW) method have been used to explore the chemical and biological processes.

Detailed MD simulations were performed to study the transportation of NH₄⁺, NH₃ and H₂O through the Escherichia coli ammonium transporter (AmtB) membrane protein. A periplasmic recruitment vestibule was identified and the entrance of an NH₄⁺ into this vestibule requires only 3.1 kcal/mol. In the end of this vestibule, the phenyl ring of Phe107 dynamically opens and …

Photoactive Supramolecular Cyclodextrin Assemblies, Muath Atmeh

Doctoral

Ligands with a macrocyclic host unit attached to a photoactive metal core are of interest across a range of applications from luminescent or electrochemical sensors, light harvesting and energy-collection purposes. Their versatile properties and possibility of associating cyclodextrins with other molecules both covalently and non-covalently mean that these macrocyclic ligands can be employed in the design and the formation of supramolecular complexes. A particularly attractive proposition is to combine the selective inclusion capabilities of CD with luminophores which may act as reporters of binding or other interactions at the cyclodextrin cavity. Ruthenium, osmium, and iridium polypyridyl complexes are particularly attractive …

Blocked Localized Wavefunction Analysis Of Π And Σ Bonds In The Metal Carbonyl, Kazuhito Nakashima

Masters Theses

The bonding features in group 10 and 11 metal carbonyls Ni(CO), Pd(CO), Pt(CO), [Cu(CO)]+, [Ag(CO)]+, and [Au(CO)]+ have been studied with BLW method. The carbon monoxide is well known as both a π acceptor and a σ donor. The π back bonding and o bonding are synergistic in these metal carbonyl complexes, because the π donation from the metals polarizes the metals and creates a negative force field as an additional driving force on the σ donation from the carbon end of CO vice versa. The synergistic effect in the metal-carbonyl bonds can be described by decomposing the binding energy …

Bis[(Dimethyl-Λ4-Sulfanylidene)Oxonium] Hexabromidotellurate(Iv) Dimethyl Sulfoxide Disolvate, Martin D. Rudd, Gregory Kokke, Sergey V. Lindeman

Chemistry Faculty Research and Publications

No abstract provided.

Carbon Nanotube Array Electrodes Based Supercapacitors With 3.5v Working Voltage, Hao Zhang, Gao-Ping Cao, Yu-Sheng Yang, Zhen-Nan Gu, Bin Xu, Wen-Feng Zhang

Journal of Electrochemistry

The carbon nanotube arrays(CNTA) were grown directly on the substrates of Ta and stainless steel by chemical vapor deposition.The button-like supercapacitors were fabricated based the CNTA electrodes.The electrochemical performance of CNTA based supercapacitors presentsed high working voltage(3.5 V),long cycle life,and good rate capability.The power and energy densities are were 928 kW·kg^-1 and 19 Wh·kg^-1,respectively(based on the mass of CNTA).

Direct Electrochemistry Of God On Glassy Carbon Electrode Modified With Mesoporous Carbon, Kun-Qi Wang, Lin Zhu, Wei Xing

Journal of Electrochemistry

Glucose oxidase(GOD) is immobilized on glassy carbon electrode mesoporous carbon by simple method.Cyclic voltammetric results indicated that on GOD of the modified electrode a quasi-reversible redox reaction took place(GCE) surface modified at a formal potential of-0.4294 V in 0.1 mol/L phosphate buffer solution(PBS)(pH 7.1).The electrochemical reaction consisted of a two-electron transfer coupled with a two-proton transfer.The GOD can completely catalyze oxidation of glucose via electron transfer intermedia of ferrocene monocarboxylic acid(FMCA) in saturated solutions with N₂.The bioactivity of GOD on the modified electrode with mesoporous carbon was obviously unattacked.

Synthesis And Electrochemical Characteristics Of Li[Li(0.167)Mn(0.583)Ni(0.25)]O2 Cathode Material, Ling-Yan Yu, Wei-Hua Qiu, Fang Lian, Jia-Yuan Huang, Xao-Li Kang, Wei Liu

Journal of Electrochemistry

The cathode material of Li[Li_0.167Mn_0.583Ni_0.25]O₂ was synthesized by low-heat solid state reaction.The results of XRD and FESEM indicated that the powders of the material were well crystallized with the uniform diameters ranging from 60 nm to 100 nm and could be indexed as α-NaFeO₂ structure(R3-m space). Galvanostatic charge-discharge tests showed that the electrode delivered the capacity of about 120 mAh/g with good cyclability when cycled in 2.5~4.4V at 0.5C. When the cut-off potential was set up to 4.6V, the cathode delivered much larger capacities with the maximum of 234 mAh/g. It was …

Electrochemical Performance Of C-Lifepo4 By Polyaniline Doping, Wei Wang, Li-Fang Jiao, Hua-Tang Yuan

Journal of Electrochemistry

The olivine LiFePO₄ cathode materials were synthesized using the solid state method in an inert atmosphere by doping polyaniline into the C-LiFePO₄.It was found that the electrochemical performance of polyaniline-doped C-LiFePO₄ slightly improved.At a low discharging rate(0.1C), the capability of(C-LiFePO₄)0.9(PANI)0.1 reached 164 mAh·g^-1.When the charge-discharge rate is increased to 0.5C and 1.0C,the showed capacities of 121.6 mAh·g^-1 and 110.1 mAh·g^-1 were obtained,respectively.

Electrocatalytic Performance Of Pt/C And Pt/Wo3/C Catalysts For Methanol Oxidation, Yuan-Yuan Chu, Bing Wu, Ya-Wen Tang, Tian-Hong Lu, Ying Gao

Journal of Electrochemistry

The catalysts of Carbon supported Pt(Pt/C) and carbon supported Pt/WO₃(Pt/WO₃/C) were prepared with liquid phase reduction method.It was found that the catalytic activity and stability of the Pt/WO₃/C catalysts were increased with the addition of WO₃.When the atomic ratio of Pt and W was 1∶1,the best electrocatalytic performance of the Pt/WO₃/C catalyst for the methanol oxidation was obtained.This is attributed to the larger electrochemical surface area of Pt/WO₃/C and the weeker adsorption of CO towards the catalyst.

Performance Of Air Breathing Direct Methanol Fuel Cell Under Ambient Condition, Jian-Guo Liu, Jun Gu, Tao Yu, Zhi-Gang Zou, T.S Zhao

Journal of Electrochemistry

The performance of the passive DMFC was systematically investigated under an ambient condition by simulating a wide range of temperature and humidity in a high-quality environmentally controlled room.The results indicated that the performance of the passive DMFC was nearly independent of ambient humidity from 30% to 90% RH and water produced in the cathode was expelled mostly from the cell in a liquid state.Compared with the humidity,the ambient temperature has a significant effect on the performance of the passive DMFC.The power density of 30 mW·cm^-2 were obtained at 40℃,while only 10 mW·cm^-2 at 10 ℃.