Chemistry Commons^™

Recent Applications Of Flame Atomic Absorption Spectrometry To Environmental Measurements, Michael A. Janusa

Faculty Publications

Atomic absorption spectroscopy is very useful for the determination of a large number of elements, especially at trace levels. It is a widely used technique for analysis of a wide variety of sample matrices including biota, soils, and water. Atomic absorption spectroscopy is a very reputable technique that is inexpensive and delivers accurate results even in a complex matrix. This review focuses on the applications of flame atomic absorption spectroscopy to environmental measurements, and is mainly based on papers published from 1999–2002.

“[Cu(Pyrazine-2-Carboxylate)2]2Cd4I8: Unprecedented 1-D Serpentine Chains And Regular 2-D Regular Metal-Organic Square Grids In A 3-D Framework., Delia M. Ciurtin, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

A novel three-dimensional coordination polymer containing
an unprecedented one-dimensional serpentine motif conjoined
with a two-dimensional square grid motif is presented.

Three Unique Coordination Geometries Involving 1,2-Dimethoxy-4,5-Bis(2-Pyridylethynyl)Benzene, Jeffrey E. Fiscus, Sandra Shotwell, Ralph C. Layland, Mark D. Smith, Hans Conrad Zur Loye, Uwe H. F. Bunz

Faculty Publications

Reaction of the new ligand 1,2-dimethoxy-4,5-bis(2-pyridylethynyl) benzene with different metal centers under similar reaction conditions led to three distinct structure formation processes: molecular ring closure, dimerization, and polymer formation.

Ca4Iro6, Ca3Mgiro6 And Ca3Zniro6, Matthew J. Davis, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

Single crystals of tetracalcium iridium hexaoxide, Ca₄IrO₆, tricalcium magnesium iridium hexaoxide, Ca₃MgIrO₆, and tricalcium zinc iridium hexaoxide, Ca₃ZnIrO₆, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The three compounds are isostructural and adopt the K₄CdCl₆ structure type, comprised of chains of alternating face-shared [CaO₆], [MgO₆] or [ZnO₆] trigonal prisms and [IrO₆] octahedra, surrounded by columns of Ca²⁺ ions.

Formula: Ca₄IrO₆, Ca_3.34Mg_0.66IrO₆ and …

A Dipolar Coupling Based Strategy For Simultaneous Resonance Assignment And Structure Determination Of Protein Backbones, Fang Tian, Homayoun Valafar, James H. Prestegard

Faculty Publications

A new approach for simultaneous protein backbone resonance assignment and structure determination by NMR is introduced. This approach relies on recent advances in high-resolution NMR spectroscopy that allow observation of anisotropic interactions, such as dipolar couplings, from proteins partially aligned in field ordered media. Residual dipolar couplings are used for both geometric information and a filter in the assembly of residues in a sequential manner. Experimental data were collected in less than one week on a small redox protein, rubredoxin, that was 15N enriched but not enriched above 1% natural abundance in 13C. Given the acceleration possible with partial 13C …

Two Different One-Dimensional Structural Motifs In The Same Coordination Polymer: A Novel Interpenetration Of Infinite Ladders By Bundles Of Infinite Chains, Badruz Zaman, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

A coordination polymer with a novel structural motif
consisting of stacks of infinite ladders interpenetrated by
bundles of infinite chains is described; geometrical arguments
are made for the requirements that can lead to such
interpenetration as a function of ligand dimensions.

Crystal Growth, Structure Determination And Magnetism Of A New Hexagonal Rhodate: Ba9rh8o24, Katharine E. Stitzer, M. D. Smith, J. Darriet, Hans Conrad Zur Loye

Faculty Publications

Single crystals of Ba9Rh8O24, grown from a molten potassium carbonate flux, crystallize in the spacegroup R¯3c with lattice parameters of a = 10.0899(4) and c = 41.462(2) Å. Magnetic measurements on oriented single crystals reveal the existence of magnetic anisotropy

Shape Imprinting Due To Variable Disulfide Bonds In Polyacrylamide Gels, Andrew B. Greytak, Alexander Y. Grosberg, Toyoichi Tanaka

Faculty Publications

Through the use of variable disulfide crosslinkers, we have created polyacrylamide gels whose shape can be altered after polymerization. N,N'-bisacryloylcystamine is incorporated as a crosslinker, along with a smaller amount of a permanent crosslinker. After polymerization, the disulfide bonds are cleaved into thiols through reduction. By reoxidizing the thiols with the gel held in a new macroscopic shape, a new set of disulfide bonds is formed, and the gel is forced to adopt the new shape. Retension of the new shape improves with greater distortion from the original shape, as well as with increased concentration of variable …

Sr3Znpto6 And Sr3Cdpto6, Mark D. Smith, Hans Conrad Zur Loye

Faculty Publications

The flux synthesis of single crystals of the isostructural compounds tristrontium zinc platinum hexaoxide, Sr₃ZnPtO₆, and tristrontium cadmium platinum hexaoxide, Sr₃CdPtO₆, is reported. The compounds adopt the pseudo-one-dimensional rhombohedral K₄CdCl₆ structure type, and feature chains of face-shared distorted ZnO₆ or CdO₆ trigonal prisms and PtO₆ octahedra, surrounded by columns of Sr²⁺ ions. All transition metals are located on the threefold axis of symmetry, while the Sr²⁺ cations lie on twofold axes.

Formula: Sr₃ZnPtO₆ and Sr₃CdPtO₆

Process For Immobilizing Waste Using Bagasse (Us Patent 6174275), Michael A. Janusa

Faculty Publications

No abstract provided.

Semiclassical Application Of The Mo”Ller Operators In Reactive Scattering, Sophya Garashchuk, John C. Light

Faculty Publications

Mo\ller operators in the formulation of reaction probabilities in terms of wave packet correlation functions allow us to define the wave packets in the interaction region rather than in the asymptotic region of the potential surface. We combine Mo\ller operators with the semiclassical propagator of Herman and Kluk. This does not involve further approximations and can be used with any initial value representation (IVR) semiclassical propagator. Time propagation in asymptotic regions of the potential due to Mo\ller operators reduces the oscillations of the propagator integrand and improves convergence of the results with respect to the number of trajectories. The effectiveness …

An Alternative Use For Bagasse: Stabilizing Agent For Lead Waste, Michael A. Janusa

Faculty Publications

Bagasse amounts to one- third of the cane ground and supplies fuel for the generation of steam in raw factories; however, most factories have an excess of bagasse during regular grinding season. Another method for the utilization of bagasse was investigated using bagasse as a stabilizing agent for heavy metal waste solidified /stabilized in cement. Lead nitrate was used as the model heavy me ta l waste with a 10 or 15 per cent lead by weight to cement loading. Samples were cured for 7, 14, and 28 days at 24°C. Samples containing bagasse typically resulted in TCLP extract lead …

Self-Assembly Of A Bis-Urea Macrocycle Into A Columnar Nanotube, Linda S. Shimizu, Mark D. Smith, A. D. Hughes, Ken D. Shimizu

Faculty Publications

A bis-urea macrocycle 1 was synthesized and shown to form extended nanotubular columns byX-ray crystallography.

Structure Determination Of Ba8Corh6O21, A New Member Of The 2h-Perovskite Related Oxides, Hans Conrad Zur Loye, M. D. Smith, K. E. Stitzer, A. El Abed, J. Darriet

Faculty Publications

Single crystals of Ba₈CoRh₆O₂₁ were grown out of a potassium carbonate flux. The structure was solved by a general method using the superspace group approach. The superspace group employed was R3m(00γ)0s with a = 10.0431(1) Å, c₁ = 2.5946(1) Å and c₂ = 4.5405(1) Å, V = 226.60(1) ų. Ba₈CoRh₆O₂₁ represents the first example of an m = 5, n = 3 member of the A_3n+3mA'_nB_3m+nO_9m+6n family of 2H hexagonal perovskite related oxides and contains chains consisting of six …

Design Of Peptides With, Α,Β-Dehydro-Residues: A Dipeptide With A Branched Β-Carbon Dehydro-Residue At The (I+1) Position, Methyl N-(Benzyloxycarbonyl)-Α,Β-Didehydrovalyl-L-Tryptophanate, Vijayaraghavan Rangachari, Pravindra Kumar, Sharmistha Dey, Tej P. Singh

Faculty Publications

The structure of the title peptide, C₂₅H₂₇N₃O₅, has been determined and its conformation analysed. Values of the standard peptide torsion angles are φ(1) = -44.2 (3)°, ψ(1) = 135.9 (2)°, φ(2) = -141.6 (2)° and ψ(T/2) = 168.0 (2)°. The crystal structure is stabilized by an intermolecular hydrogen bond, with an N···O distance of 2.919 (3)Å, which is formed between screw-axis-related NH and CO groups of dehydrovaline residues.

Simplified Calculation Of The Stability Matrix For Semiclassical Propagation, Sophya Garashchuk, John C. Light

Faculty Publications

We present a simple method of calculation of the stability (monodromy) matrix that enters the widely used semiclassical propagator of Herman and Kluk and almost all other semiclassical propagators. The method is based on the unitarity of classical propagation and does not involve any approximations. The number of auxiliary differential equations per trajectory scales linearly rather than quadratically with the system size. Just the first derivatives of the potential surface are needed. The method is illustrated on the collinear H[sub 3] system.

The Environmental Science Minor: A Disciplinary Approach To Interdisciplinary Studies With A Grounding In Undergraduate Research, Brian E. Bodenbender, Edward C. Hansen, Graham F. Peaslee, Jonathan W. Peterson

Faculty Publications

No abstract provided.

Nonsteroidal Anti-Inflammatory Drugs, Acetaminophen, Cyclooxygenase 2, And Fever, Daniel L. Simmons, David Wagner, Kenneth Westover

Faculty Publications

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used antipyretic agents that most probably exert their antifever effect by inhibiting cyclooxygenase (COX)–2. Thus, COX-2–selective drugs or null mutation of the COX-2 gene reduce or prevent fever. Acetaminophen is antipyretic and analgesic, as are NSAIDs, but it lacks the anti-inflammatory and anticoagulatory properties of these drugs. This has led to the speculation that a COX variant exists that is inhibitable by acetaminophen. An acetaminophen-inhibitable enzyme is inducible in the mouse J774.2 monocyte cell line. Induction of acetaminophen-inhibitable prostaglandin E2 synthesis parallels induction of COX-2. Thus, inhibition of pharmacologically distinct COX-2 enzyme activity by …

Effect Of Collagen Turnover On The Accumulation Of Advanced Glycation End Products, Nicole Verzijl, Jeroen Degroot, Suzanne R. Thorpe, Ruud A. Bank, J. Nikki Shaw, Timothy J. Lyons, Johannes Wj Bijlsma, Floris Pjg Lafeber, John W. Baynes, Johan M. Tekoppele

Faculty Publications

Collagen molecules in articular cartilage have an exceptionally long lifetime, which makes them susceptible to the accumulation of advanced glycation end products (AGEs). In fact, in comparison to other collagen-rich tissues, articular cartilage contains relatively high amounts of the AGE pentosidine. To test the hypothesis that this higher AGE accumulation is primarily the result of the slow turnover of cartilage collagen, AGE levels in cartilage and skin collagen were compared with the degree of racemization of aspartic acid (% D-Asp, a measure of the residence time of a protein). AGE (Ne- (carboxymethyl)lysine, Ne-(carboxyethyl)lysine, and pentosidine) and % D-Asp concentrations increased …

Alpha Particle Emission From6he + 209bi , D. Lizcano, E. F. Aguilera, E. Martínez-Quiroz, J. J. Kolata, V. Guimarães, D. Peterson, P. Santi, R. White-Stevens, F. M. Nunes, F. D. Becchetti, M. Y. Lee, T. O'Donnell, P. A. Deyoung, M. Goupell, B. Hughey, A. Nowlin, Graham F. Peaslee

Faculty Publications

In a recent experiment, we have for the first time studied near-barrier and sub-barrier fusion of the exotic "Borromean" nucleus 6He with 209Bi and found that the sub-barrier fusion of this system is exceptionally enhanced, implying a 20% reduction in the nominal fusion barrier. It was suggested that this striking effect might he due to coupling to positive Q-value neutron transfer channels, leading to "neutron flow" and consequent neck formation between the projectile and target. The results of a new experiment using the radioactive nuclear beam facility at the University of Notre Dame to measure fast ⍺-particle emission from 6He …

Pyridoxamine, An Inhibitor Of Advanced Glycation Reactions, Also Inhibits Advanced Lipoxidation Reactions: Mechanism Of Action Of Pyridoxamine, Joelle M. Onorato, Alicia J. Jenkins, Suzanne R. Thorpe, John W. Baynes

Faculty Publications

Maillard or browning reactions lead to formation of advanced glycation end products (AGEs) on protein and contribute to the increase in chemical modification of proteins during aging and in diabetes. AGE inhibitors such as aminoguanidine and pyridoxamine (PM) have proven effective in animal model and clinical studies as inhibitors of AGE formation and development of diabetic complications. We report here that PM also inhibits the chemical modification of proteins during lipid peroxidation (lipoxidation) reactions in vitro, and we show that it traps reactive intermediates formed during lipid peroxidation. In reactions of arachidonate with the model protein RNase, PM prevented modification …

Ac Susceptibility Of Sr3CuptXIr1-XO6: A Magnetic System With Competing Interactions And Dimensionality, S H. Irons, T D. Sangrey, K M. Beauchamp, M D. Smith, Hans Conrad Zur Loye

Faculty Publications

Sr₃CuPt_xIr_1-xO₆ has been cited as an example of a one-dimensional quantum spin chain with competing ferromagnetic and antiferromagnetic interactions. We have measured the ac susceptibility of Sr₃CuPt_xIr_1-xO₆ with x=0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7, in magnetic fields of 0–60 kOe, and at temperatures down to 0.275 K. Our data show that the x=endpoint Sr₃CuIrO₆, exhibits long-range ferromagnetic order at T=20.1 K, contrary to results from dc susceptibility studies which indicated that it remained a one-dimensional ferromagnet to below 4 …

Thermolysis Of Semicarbazones To The Corresponding Azines Through Reactive N-Substituted Isocyanate Intermediates, Shailesh N. Shah, N.K. Chudgar

Faculty Publications

Thermolysis of semicarbazones (I) to azines (II) occurs through reactive N-substituted isocyanate intermediates (Ia) which can be converted in situ to carbamates and N-substituted ureas.

Effect Of Interfacial Tension On Propagating Polymerization Fronts, R. Texier-Picard, John A. Pojman, Vitaly Volpert

Faculty Publications

This paper is devoted to the investigation of polymerization fronts converting a liquid monomer into a liquid polymer. We assume that the monomer and the polymer are immiscible and study the influence of the interfacial tension on the front stability. The mathematical model consists of the reaction-diffusion equations coupled with the Navier-Stokes equations through the convection terms. The jump conditions at the interface take into account the interfacial tension. Simple physical arguments show that the same temperature distribution could not lead to Marangoni instability for a nonreacting system. We fulfill a linear stability analysis and show that interaction of the …

Aqueous Equilibria: Acids, Bases, And Solubility. A General Chemistry Laboratory Experiment, Michael A. Janusa

Faculty Publications

We refer to two major types of general chemistry freshman laboratory experiments: discovery and cookbook. The typical Freshman enrolled in general chemistry has the skills to perform an experiment that is somewhere between cookbook and discovery, and we have developed a laboratory experiment that is midway between these extremes. This experiment aids the student's understanding of the concept of aqueous equilibria. In this experiment, students are asked to prepare and measure the pH of a variety of acidic and basic solutions. Students are also asked to calculate pH values from literature dissociation constants and dissociation constants from their experimental pH …

Solidification / Stabilization Of Lead With The Aid Of Bagasse As An Additive To Portland Cement, Michael A. Janusa

Faculty Publications

Solidification/stabilization (S/S) of hazardous waste is a widely used technology; therefore, it is crucial to evaluate its effectiveness and make attempts to improve the technique. A better matrix for S/S of hazardous waste was designed that is effective and economically feasible. This was accomplished by adding bagasse (byproduct of milling or diffusing sugar cane) to the waste/cement matrix. Lead nitrate was used as the model heavy metal waste with a 10or 15% lead by weight to cement loading. Samples were cured for 7, 14, and 28 days at 24°C. Samples containing bagasse typically resulted in TCLP (modified) extract lead concentrations …

Palladium-Catalyzed Carboxylative Coupling Of Allylstannanes And Allyl Halides, Russell J. Franks

Faculty Publications

A three-component carboxylative coupling between allyl halides, allylstannanes, and CO2 to produce allyl esters is catalyzed by Pd and Pt phosphine complexes. Allyl chloride and allyltributylstannane are thus converted to propenyl butenoate in excellent yield. Cross coupling of two different allyl components produces a nearly statistical mixture of all four possible esters. Tentative mechanistic pathways for the catalytic reaction are proposed.

Trimethyl(Trifluorovinyl)Silane, Roxana M. Trifu, George L. Gould

Faculty Publications

No abstract provided.

Structural And Electrical Characterization Of A Novel Mixed Conductor: Ceo2 - Sm2O3 - Zro2 Solid Solution, W. Huang, P. Shuk, M. Greenblatt, M. Croft, Fanglin Chen, M. Liu

Faculty Publications

solid solutions were synthesized for the first time by the hydrothermal method. The electrical properties of the solid solutions have been studied in air and under reducing conditions. Solid solutions with the fluorite structure were formed in all of the studied range of substitution after calcination at 1500°C. With increasing substitution up to 30 mol %, the electronic conductivity increases under a reducing atmosphere. The solid solution has good mixed electronic and ionic conductivity; the total conductivity is 0.42 S/cm at and 700°C with an estimated ionic conductivity of ca. .

Pretransitional Behavior Above The Nematic-Isotropic Phase Transition Of An Auxetic Trimer Liquid Crystal, Daeseung Kang, Milind P. Mahajan, Shiyong Zhang, Rolfe G. Petschek, Charles Rosenblatt, Chaobin He, Puwei Lu, A.C. Griffin

Faculty Publications

Static Light scattering and electric field-induced Kerr measurements were performed above the nematic-isotropic phase transition of a terminal-lateral-lateral-terminal negative Poisson ratio trimer. Far both measurements the inverse susceptibility was observed to be nearly linear with temperature, a result inconsistent with our previously reported Kerr data [Phys. Rev. E 58, 2041 (1998)]. [S1063-651X(99)11010-9].