Physical Sciences and Mathematics Commons^™

Realization Of Random-Field Ising Ferromagnetism In A Molecular Magnet, Bo Wen, P Subedi, Lin Bo, Y Yeshurun, M P. Sarachik, A D. Kent, A J. Millis, Christos Lampropoulos, G Christou

Christos Lampropoulos

The longitudinal magnetic susceptibility of single crystals of the molecular magnet Mn12-acetate obeys a Curie-Weiss law, indicating a transition to a ferromagnetic phase at ∼0.9 K. With increasing magnetic field applied transverse to the easy axis, a marked change is observed in the temperature dependence of the susceptibility, and the suppression of ferromagnetism is considerably more rapid than predicted by mean-field theory for an ordered single crystal. Our results can instead be fit by a Hamiltonian for a random-field Ising ferromagnet in a transverse magnetic field, where the randomness derives from the intrinsic distribution of locally tilted magnetic easy axes …

Experimental Determination Of The Weiss Temperature Of Mn12-Ac And Mn12-Ac-Meoh, Christos Lampropoulos, Shiqi Li, Lin Bo, Bo Wen, M P. Sarachik, P Subedi, A D. Kent, Y Yeshurun, A J. Millis, S Mukherjee, G Christou

Christos Lampropoulos

We report measurements of the susceptibility in the temperature range from 3.5 to 6.0 K of a series of Mn12-ac and Mn12-ac-MeOH samples in the shape of rectangular prisms of length lc and square cross section of side la. The susceptibility obeys a Curie-Weiss law, χ=C/(T−θ), where θ varies systematically with sample aspect ratio. Using published demagnetization factors, we obtain θ for an infinitely long sample corresponding to intrinsic ordering temperatures Tc≈0.85 K and ≈0.74 K for Mn12-ac and Mn12-ac-MeOH, respectively. The difference in Tc for two materials that have nearly identical unit cell volumes and lattice constant ratios suggests …

Beyond The Chemistry Web, Robert A. Buchanan

Sci-Tech News

No abstract provided.

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

Hans Conrad zur Loye

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.

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

Hans Conrad zur Loye

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 …

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

Hans Conrad zur Loye

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 …

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

Hans Conrad zur Loye

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

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

Hans Conrad zur Loye

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.

Catena-Poly[[Bis(Α-Thenoyltrifluoroacetonato)Copper(Ii)]-Μ-1,4-Di-4-Pyridyl-2,3-Diazabuta-1,3-Diene], William J. Perkins, Tamara Maxwell, Mark D. Smith, Leroy Peterson Jr., Hans Conrad Zur Loye

Hans Conrad zur Loye

In the one-dimensional title polymer, [Cu(C₈H₄F₃O₂S)₂(C₁₂H₁₀N₄)]_n or [Cu(L)₂(tta)₂] [tta is -thenoyltrifluoroacetonato and L is 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene], Cu²⁺ lies on a center of inversion. It is axially coordinated by two pyridyl N atoms from two different L ligands and equatorially coordinated by four O atoms from two chelating tta ligands. The ligand L propagates the one-dimensional chain structure by serving as a bridging ligand between two Cu octahedra via Cu-N coordinate bonds.

Sm2Nairo6, A Monoclinically Distorted Double Perovskite, Samuel J. Mugavero Iii, Irina V. Puzdrjakova, Mark D. Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

Single crystals of the lanthanide-containing iridate, disamarium sodium iridium hexaoxide, Sm₂NaIrO₆, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/n and is a double perovskite, consisting of a 1:1 ordered rock-salt-type lattice of corner-shared NaO₆ and IrO₆ distorted octahedra. Samarium occupies the eightfold coordination site generated by the connectivity of the octahedra.

Diaquabis(5-Fluoro-2-Hydroxybenzoato-Κo1)Zinc(Ii), Diana Rishmawi, Jennifer Kelley, Mark D. Smith, Leroy Peterson, Hans Conrad Zur Loye

Hans Conrad zur Loye

The title compound, [Zn(C₇H₄FO₃)₂(H₂O)₂], is a monomeric Zn^II complex. The Zn^II atom, which lies on a twofold rotation axis, is situated in a distorted tetrahedral environment composed of two monodentate carboxlyate O atoms and two water O atoms. O-HO hydrogen bonds link these units, forming sheets that are stacked along the c axis.

Catena-Poly[[Bis(Α-Thenoyltrifluoroacetonato-Κ2O,O')Copper(Ii)]-Μ-1,4-Di-3-Pyridyl-2,3-Diaza-1,3-Butadiene-Κ2N:N'], William J. Perkins, Tamar Maxwell, Ken B. Williams, Andrea M. Goforth, Mark D. Smith, Leroy Peterson Jr., Hans Conrad Zur Loye

Hans Conrad zur Loye

The title compound, [Cu(C₈H₄F₃O₂S)₂(C₁₂H₁₀N₄)]_n or [Cu(tta)₂(L2)₂]_n (L2 = 1,4-di-3-pyridyl-2,3-diaza-1,3-butadiene and tta = -thenoyltrifluoroacetonate), consists of undulating chains containing two crystallographically distinct Cu^II centers that are each located on inversion centers. Each Cu^II center exhibits distorted octahedral coordination provided by two pyridyl N atoms from two equivalent L2 ligands and four O atoms from two equivalent tta ligands. The chains interact through weak C-FH-C contacts.

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

Hans Conrad zur Loye

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

Poly[[(Μ-2,2'-Bipyrimidine-Κ4N1,N1':N3,N3')(Μ-Sulfato-Κ2O:O')Zinc(Ii)] Monohydrate], Aaron Oxendine, Jennifer Kelley, Leroy Peterson Jr., Mark D. Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

In the title compound, {[Zn(SO4)(C8H6N4)]·H2O}n, the ZnII atom is in a distorted octahedral environment. The ZnII atoms are bridged by both 2,2'-bipyrimidine and sulfate ligands, thus forming a three-dimensional polymeric metal-organic solid that contains uncoordinated water molecules in the interstitial space. O-HO hydrogen bonding consolidates the crystal structure.

Open Data, Open Source, And Open Standards In Chemistry: The Blue Obelisk Five Years On, Andrew Lang, Noel M. O'Boyle, Rajarshi Guha, Egon Willighagen, Samuel Adams, Jonathan Alvarsson, Jean-Claude Bradley, Igor Filippov, Robert M. Hanson, Marcus D. Hanwell, Geoffrey R. Hutchison, Craig A. James, Nina Jeliazkova, Karol M. Langner, David C. Lonie, Daniel M. Lowe, Jerome Pansanel, Dmitry Pavlov, Ola Spjuth, Christoph Steinbeck, Adam L. Tenderholt, Kevin J. Theisen, Peter Murray-Rust

College of Science and Engineering Faculty Research and Scholarship

Background: The Blue Obelisk movement was established in 2005 as a response to the lack of Open Data, Open Standards and Open Source (ODOSOS) in chemistry. It aims to make it easier to carry out chemistry research by promoting interoperability between chemistry software, encouraging cooperation between Open Source developers, and developing community resources and Open Standards. Results: This contribution looks back on the work carried out by the Blue Obelisk in the past 5 years and surveys progress and remaining challenges in the areas of Open Data, Open Standards, and Open Source in chemistry. Conclusions: We show that the Blue …

The Regulation Of Skeletal Muscle Protein Turnover During The Progression Of Cancer Cachexia In The ApcMin/+ Mouse, James P. White, John W. Baynes, Stephen L. Welle, Matthew C. Kostek, Lydia E. Matesic, Shuichi Sato, James A. Carson

Faculty Publications

Muscle wasting that occurs with cancer cachexia is caused by an imbalance in the rates of muscle protein synthesis and degradation. The Apc(Min/+) mouse is a model of colorectal cancer that develops cachexia that is dependent on circulating IL-6. However, the IL-6 regulation of muscle protein turnover during the initiation and progression of cachexia in the Apc(Min/+) mouse is not known. Cachexia progression was studied in Apc(Min/+) mice that were either weight stable (WS) or had initial (≤5%), intermediate (6-19%), or extreme (≥20%) body weight loss. The initiation of cachexia reduced %MPS 19% and a further ∼50% with additional weight …

Cucurbit[8]Uril Rotaxanes, Vijayakumar Ramalingam, Adam R. Urbach

Chemistry Faculty Research

The synthesis of [2]rotaxanes, each comprising a viologen core threaded through a cucurbit[8]uril (Q8, Figure 1) macrocycle and stoppered by tetraphenylmethane groups, and their binding to second guests as inclusion complexes in organic and aqueous media are described. Stoppering was observed to have little effect on binding. Chemical modification of the threaded guest was used to control solubility and binding characteristics, thus demonstrating a novel approach to making artificial receptors with readily modifiable properties.

Creation Of Post Ap Chemistry Class, Julian Medrano

Theses and Dissertations - UTB/UTPA

The creation of a Post AP Chemistry Class to be taught at the high school level for grade 12 students is discussed. The class is to be taught under the supervision of the University of Texas Pan American professors and taught by an MS Chemistry teacher, in order to better transition students into upper level chemistry courses beyond Chemistry 1401 and 1402.

Chemical Education Experiences From The English Language Learner Perspective, Annette Flores

Theses and Dissertations - UTB/UTPA

The Rio Grande Valley (RGV) is a region populated by Spanish-speaking immigrants and their descendants producing a large English Language Learner (ELL) student population. ELLs have historically had low literacy rates and achievement levels when compared to their counterparts. In order to address this achievement gap, previous research efforts and curriculum interventions have focused on language acquisition as being the determining factor in ELL education, with little attention given to academic content acquisition. More current research efforts have transitioned into English language acquisition through academic content instruction; this present research study specifically focuses on ELL experiences in chemistry. Participants were …

Efficient Quantum Trajectory Representation Of Wavefunctions Evolving In Imaginary Time, Sophya V. Garashchuk, James Mazzuca, Tijo Vazhappilly

Faculty Publications

The Boltzmann evolution of a wavefunction can be recast as imaginary-time dynamics of the quantum trajectory ensemble. The quantum effects arise from the momentum-dependent quantum potential – computed approximately to be practical in high-dimensional systems – influencing the trajectories in addition to the external classical potential [S. Garashchuk, J. Chem. Phys.132, 014112 (2010)]. For a nodelesswavefunction represented as ψ(x, t) = exp ( − S(x, t)/ℏ) with the trajectory momenta defined by ∇S(x, t), analysis of the Lagrangian and Eulerian evolution shows that for bound potentials the former …

Green Decarbonylation Of Aldehydes Using Palladium (Ii) Acetate, Jessica Konopka

Pell Scholars and Senior Theses

Decarbonylation reactions are important reactions in the chemical industry with typical methods being costly and wasteful. It is important to determine an effective catalyst and to see how general the reaction is with varying aldehydes, as well as to reduce the waste and make the reaction more cost effective. Several different aldehydes were studied using palladium (II) acetate as a catalyst. The samples were analyzed using Gas Chromatography Mass Spectroscopy (GC-MS) to determine if a product was formed based on the percent report obtained. Palladium (II) acetate was found to be an effective catalyst, yielding 100% product for several aldehydes …

Utilizing Service-Learning In The Analytical Chemistry Laboratory: Soil And Water Analysis In Rochester, New York, Kimberly D. Chichester, Irene Kimaru, Lynn Donahue, Maryann Herman

Chemistry Faculty/Staff Publications

For an analytical chemistry course at St. John Fisher College, instructors designed a servicelearning project on soil and water analysis to achieve the following two goals: 1) to introduce analytical chemistry students to soil- and water-testing methods by working in collaboration with surrounding neighborhoods residents and government agencies and 2) to prepare written reports of the results for the designated community partners. Service-learning students conducted soil testing for lead on homes and perspective community garden sites around Rochester, NY with plans to establish planting methods to revitalize polluted soil. Four different communities contributed soil samples. The entire project was performed …

Design, Synthesis And Studies Directed Towards The Photophysical Properties Of The Polycyclic Aromatic Hydrocarbons, Rekha Sharma

Master's Theses (2009 -)

The cross conjugated molecules are also known as cruciforms, which effectively allow the HOMO-LUMO separation. The term Cruciform is used for diaxial chromophores in which the properties of the two axes can be manipulated upon suitable substitution with auxochromic substituents. Originally designed for molecular electronic applications, the discovery that these cruciforms possess a platform where Frontier Molecular Orbitals can be tuned, led to their investigative research as sensory flourophores. In the majority of organic chromophores, the HOMO and the LUMO are congruent. Thus, upon binding to an analyte both HOMO and LUMO are almost equally affected and hence large shifts …

Generation Of Diverse Molecular Complexity From Simple Hydrocarbons, Anobick Sar

Dissertations (1934 -)

In an effort to make diverse molecular complexity from simple hydrocarbons, tricarbonyl(cyclohexadienyl)iron(+1) cation was prepared in two steps from 1, 3-cycloxehadiene. Reactivity of the symmetric iron cation with heteroatom nucleophiles and stabilized carbon nucleophiles was studied. Nucleophilic attack of potassium phthalimide at the dienyl terminus of the cation followed by oxidative decomplexation with Ce4+ provided the ligand N-(2,4-cyclohexadiene-1-yl)phthalimide. A series of stereochemically diverse polyhydroxyl aminocyclohexane "aminocyclitols" derivatives and a number of racemic and optically active hydroxy-and polyhydroxy 1,3-diaminocyclohexane derivatives have been synthesized from N-(2,4-cyclohexadiene-1-yl)phthalimide. The relative stereochemistries of the compounds ware assigned on the basis of the 1H NMR data …

Development And Applications Of Ionic Liquids And Near-Infrared Multispectral Imaging Techniques, Irena Mejac

Dissertations (1934 -)

In this work, we explore novel analytical applications of Ionic Liquids and Near-infrared multispectral imaging microscopy.

Ionic liquids (ILs) belong to a group of organic salts that are liquid at room temperature and can be, due to their unique chemical and physical properties, successfully used for a variety of applications. The main goal of this study was to explore the synergistic use of ILs in chemical separations. Specifically, chiral ILs were used as novel chiral selectors for Capillary Electrophoresis and as solvents for stationary phase in Gas Chromatography. As chiral selectors IL provides baseline-separation as well as enantiomeric separation of …

Chemistry In Second Life. Part 2. A World Of Education And Networking, Andrew Lang, Jean-Claude Bradley

College of Science and Engineering Faculty Research and Scholarship

Second Life visualisations can be scripted for immersive educational activities and real-life collaborative research. Social networking through Second Life is another spin-off for both chemists and chemistry students.

Progress Towards An Aza-Michael Addition To Ketones, Bowman Potter

Honors Theses

The aza-Michael addition to unsaturated ketones under neutral to mildly basic condition is a difficult transformation due to the inherent unreactivity of ketones toward the addition of weak nucleophiles. This thesis reports on efforts to develop an environmentally friendly, stereoselective and low-cost organo-catalyzed aza-Michael reaction between unsaturated ketones and nitrogen nucleophiles, such as phthalimide, under neutral to mildly basic conditions using the most inexpensive chiral secondary amine catalyst, proline.1 Both proline and the organic base triethylamine were found to be catalytic in the testing platform of cyclohexen-2-one and phthalimide, and another testing platform of 4-hexen-3-one and phthalimide. Likewise, when screened …

Cacao Use And The San Lorenzo Olmec, Terry G. Powis, Ann Cyphers, Nilesh W. Gaikwad, Louis Grivetti, Kong Cheong

Faculty and Research Publications

Mesoamerican peoples had a long history of cacao use—spanning more than 34 centuries—as confirmed by previous identification of cacao residues on archaeological pottery from Paso de la Amada on the Pacific Coast and the Olmec site of El Manatí on the Gulf Coast. Until now, comparable evidence from San Lorenzo, the premier Olmec capital, was lacking. The present study of theobromine residues confirms the continuous presence and use of cacao products at San Lorenzo between 1800 and 1000 BCE, and documents assorted vessels forms used in its preparation and consumption. One elite context reveals cacao use as part of a …

Characterization Of Esterase Activity From The Bacteria, Francisella Tularensis, The Causative Agent Of Tularemia, Leigh Anna Weston

Undergraduate Honors Thesis Collection

Francisella tularensis is the bacteria responsible for causing the disease tularemia and is listed as one of the top three-biowarfare agents. Among the proteins essential to the virulence and infectivity of F.tularensis are multiple esterases, which are enzymes that break down various ester, thioester, and amide bonds. In this project, the catalytic activity, substrate speci fi city, and structure of a putative esterase from F.tularensis was studied. Latent fluorophores based on the molecule, fluorescein, were unmasked by the enzymatic activity of the esterase and the increase in fluorescence was measured over time to determine how well the e tcrase recognized …

Development Of A Green Method For Amide Synthesis, Megan Ruth Darragh

Undergraduate Honors Thesis Collection

The aim of this work was to determine the scope and limitations of using microwave technology, solvent-free conditions and green chemistry-applicable solid supports for amide synthesis. We hypothesize that the method developed by Comerford et al [12] may be applicable to other solid support systems already in use (silica, fly ash, and alumina), and that combined with the use of microwave technology, green and efficient synthesis of varied amides and other dehydration reaction products may be possible. These methods should show application to undergraduate, organic chemistry laboratories as well as large-scale production laboratories.