Physical Sciences and Mathematics Commons^™

A Cucurbit[8]Uril Sponge, Vijayakumar Ramalingam, Sharon Kwee, Lisa Ryno, Adam Urbach

Adam R Urbach

This paper describes a convenient approach to quantitative removal of the synthetic host cucurbit[8]uril (Q8) from aqueous mixtures using a sepharose resin coated in memantine groups to selectively sequester Q8 in the presence of competing hosts and guests. The “Q8 sponge” can separate Q8 from Q6 and reverse the Q8-mediated dimerization of peptides.

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

Adam R Urbach

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.

Come For The Content, Stay For The Community, Hilary Eppley

Hilary J. Eppley

No abstract provided.

Combinatorial Computational Chemistry Approach To The Design Of Metal Oxide Electronics Materials, B. Rodion, Salai Ammal, Y. Inaba, Y. Oumi, S. Takami, M. Kubo, A. Miyamoto, M. Kawasaki, M. Yoshimoto, H. Koinuma

Salai C. Ammal

Combinatorial chemistry has been developed as an experimental method where it is possible to synthesize hundreds of samples all at once and examine their properties. Recently, we introduced the concept of combinatorial approach to computational chemistry for material design and proposed a new method called `a combinatorial computational chemistry'. In this approach, the effects of large number of dopants, substrates, and buffer layers on the structures, electronic states, and properties of metal oxide electronics material is estimated systematically using computer simulations techniques, in order to predict the best dopant, substrate, and buffer layer for each metal oxide electronics materials.

Building An Online Teaching Community: An Evolving Tale Ofcommunication, Collaboration, Andchemistry, Barbara Reisner, Hilary Eppley, Margret Geselbracht, Elizabeth Jamieson, Adam Johnson, Sheila Smith, Joanne Stewart, Lori Watson, Scott Williams

Hilary J. Eppley

The Interactive Online Network of Inorganic Chemists (IONiC) has grown from a small group of faculty to a national and international network focused on improving inorganicChemistry learning. IONiC’s vision is to create a community of teachers and learners who make teaching visible using social networking tools to share, discuss, test, and assess their teaching methods. The features that have allowed the IONiC community to develop and grow and IONiC’s vision for the future are described. It is likely that the lessons learned apply to other groups seeking to develop professional communities through social networking.

Ionic: A Cyber-Enabled Community Of Practice For Improving Inorganic Chemicaleducation, Hilary Eppley, Adam Johnson, Ethan Benatan, Margret Geselbracht, Joanne Stewart, Barbara Reisner, Lori Watson, B. Williams

Hilary J. Eppley

IONiC’s purpose is to enhance the inorganicChemistry classroom and laboratory experience for students and faculty members through the development of a vibrant virtual “community of practice”.

Jce Viper: An Inorganic Teaching And Learning Community, Ethan Benatan, Jezmynne Dene, Hilary Eppley, Margret Gesebracht, Elizabeth Jamieson, Adam Johnson, Barbara Reisner, Joanne Stewart, Lori Watson, B. Williams

Hilary J. Eppley

To facilitate the effective sharing of teaching tools among faculty and the development of deep subject knowledge in support of teaching, a group of faculty from predominantly undergraduate institutions has established a virtual community of inorganic chemists, IONiC (Interactive Online Network of Inorganic Chemists). Our mission is to enhance the inorganicChemistry classroom and laboratory experience for students and faculty members through the development of a vibrant, collaborative, and open community. VIPEr, the Virtual Inorganic Pedagogical Electronic Resource, is a Web site that forms the online home for our community. VIPEr is an interactive Web resource that combines a repository of …

Polymorphism In Myristoylpalmitoylphosphatidylcholine., Stephanie Tristram-Nagle, Yisrael Isaacson, Yulia Lyatskaya, Yufeng Liu, Kay Brummond, John Katsaras, John Nagle

Prof. Stephanie Tristram-Nagle Ph.D.

This study focuses on the mixed-chain lipid myristoylpalmitoylphosphatidylcholine (MPPC) near full hydration. The lipid, synthesized according to the procedure of (Mason et al., 1981a, has a low degree of acyl chain migration. When MPPC is temperature-jumped (T-jumped) from the L alpha phase (T = 38 degrees C) to T = 20 degrees C or below, a subgel phase forms; this formation takes less than 1 h at a temperature below T = 12 degrees C. The subgel remains stable up to T = 29 degrees C. When MPPC is T-jumped from the L alpha phase to T = 24 degrees …

Two-Stage Mechanism For Activation Of The Dna Replication Checkpoint Kinase Cds1 In Fission Yeast, Xu Yong, Matthew Davenport, Thomas Kelly

Matthew P Davenport

The DNA replication checkpoint is a complex signal transduction pathway, present in all eukaryotic cells, that functions to maintain genomic integrity and cell viability when DNA replication is perturbed. In Schizosaccharomyces pombe the major effector of the replication checkpoint is the protein kinase Cds1. Activation of Cds1 is known to require the upstream kinase Rad3 and the mediator Mrc1, but the biochemical mechanism of activation is not well understood. We report that the replication checkpoint is activated in two stages. In the first stage, Mrc1 recruits Cds1 to stalled replication forks by interactions between the FHA domain of Cds1 and …

Ligand-Directed Molecular Architectures: Self-Assembly Of Two-Dimensional Rectangular Metallocycles And Three-Dimensional Trigonal Or Tetragonal Prisms, Cheng-Yong Su, Yue-Ping Cai, Chun-Long Chen, Mark Smith, Wolfgang Kaim, Hans Conrad Zur Loye

Hans Conrad zur Loye

Three angular ditopic ligands (1,3-bis(benzimidazol-1-ylmethyl)-4,6-dimethylbenzene L1, 1,3-bis(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene L2, and 1,4-bis(benzimidazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene L3) and one tripodal ligand 1,3,5-tris(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene L4 have been prepared. Reaction of these shape-specific designed ligands with different metal salts affords a series of discrete molecular architectures: [Ag2L12](BF4)2 1, [Ag2L22](CF3SO3)2 2, [CF3SO3- Ag2L32]CF3SO3 3, [CF3SO3- Ag2L33]CF3SO3 4, [ClO4- Cu2L24](ClO4)3 5, [4H2O Ni2L24Cl4]·6H2O 6, [BF4- Ag3L42](BF4)2 7, [ClO4- Ag3L42](ClO4)2 8, and [CuI32- Cu3L42]2[Cu2I4] 9. The compounds were characterized by elemental analysis, ESI-MS, IR, and NMR spectroscopy, and X-ray crystallography. 1 is a dinuclear metallacycle with 2-fold rotational symmetry in which two syn-conformational L1ligands are connected by two linearly coordinated Ag+ ions. …

Exceptionally Stable, Hollow Tubular Metal-Organic Architectures: Synthesis, Characterization And Solid-State Transformation Study, Cheng-Yong Su, Andrea Goforth, Mark Smith, P. Pellechia, Hans Conrad Zur Loye

Hans Conrad zur Loye

An effective solvothermal procedure has been developed to synthesize the new three-dimensional metal−organic framework, [ZnF(AmTAZ)]·solvents, using either 3-amino-1,2,4-triazole (AmTAZ) or 3-amino-1,2,4-triazole-5-carboxylic acid (AmTAZAc) and a choice of several Zn(II) salts as starting materials. The three-dimensional structure displays open-ended, hollow nanotubular channels that are formed by hexanuclear metallamacrocyclic Zn₆F₆(AmTAZ)₆ rings. The framework integrity is maintained to 350 °C, at which point most of the guest solvent molecules have been removed, as evidenced by single-crystal X-ray analyses, ¹H solid-state NMR, and TGA measurements. At higher temperatures, the framework is converted either to zinc oxide (ZnO) when …

Self-Assembled Nanotubes That Reversibly Bind Acetic Acid Guests, Linda Shimizu, Andrew Hughes, Mark Smith, Matthew Davis, B. Zhang, Hans Conrad Zur Loye

Hans Conrad zur Loye

A large bis-urea macrocycle was synthesized and assembled into columnar nanotubes containing a sizable cavity. This purely organic nanotube is held together primarily by hydrogen bonding and yet shows remarkable thermal stability up to 180 °C in the presence and absence of acetic acid guest. This enables the nanotube to be used as reusable organic zeolite.

Tris(1,10-Phenanthroline)Cobalt(Ii) Triiodide, Meredith Tershany, Andrea Goforth, Mark Smith, Leroy Peterson, Hans Conrad Zur Loye

Hans Conrad zur Loye

The asymmetric unit of the title compound, [Co(C₁₂H₈N₂)₃](I₃)₂, contains one [Co(1,10-phenanthroline)₃]²⁺ cation, half each of two centrosymmetric triiodide anions, and one complete triiodide anion. The title compound was synthesized solvothermally from Co(NO₃)₂, 1,10-phenanthroline, and SnI₂, where the SnI₂ reagent serves only as a source of I atoms.

Tris(Ethylenediamine)Cobalt(Iii) Nonaiododibismuthate, Andrea Goforth, Rachael Hipp, Mark Smith, Leroy Peterson, Hans Conrad Zur Loye

Hans Conrad zur Loye

The asymmetric unit of the title compound, [Co(C₂H₈N₂)₃][Bi₂I₉], crystallizes in the orthorhombic space group Cmc2₁. The asymmetric unit contains half of a [Co(en)₃]³⁺ cation (en is ethylenediamine) and half of a [Bi₂I₉]^3- anion. Both species are located on mirror planes, requiring the [Co(en)₃]³⁺ cation to be present as a statistically disordered mixture of both enantiomeric forms. Crystals were grown solvothermally from an ethanol-water solvent mixture using rac-[Co(en)₃]I₃ and bismuth triiodide …

High Temperature Superconductivity In Y-Ba-Cu-O: Identification Of A Copper-Rich Superconducting Phase, Angelica Stacy, John Badding, Margret Gesselbracht, William Ham, Gary Holland, Renata Hoskins, Steven Keller, Clark Millikan, Hans Conrad Zur Loye

Hans Conrad zur Loye

For the past 15 years, advances in superconductivity have come about only slowly and even a 0.5 K increase in transition temperature was noteworthy. Until April 1986, the highest transition temperatures were near 23 K. At that time, Bednorz and Muller reported superconductivity in La-Ba-Cu-0 compounds above 30K. Following this breakthrough, there were further studies of these phases and superconductivity was found also in similar solids containing Sr and Ca instead of Ba. The superconducting phase was identified as a layered perovskite A2-xBxCu04 with tetragonal symmetry, where A = La3+ and B = Ca2+, Sr2+, or Ba2+. The Sr compounds …

Tetrakis(N-Ethyl-9-Oxo-4-Azonia-5-Aza-9h-Fluorene) Tetra-Μ3-Iodo-Hexa-Μ2-Iodo-Dodecaiodohexabismuthate, Meredith Tershany, Andrea Goforth, Mark Smith, Leroy Peterson, Hans Conrad Zur Loye

Hans Conrad zur Loye

The new iodobismuthate compound (C13H11N2O)4[Bi6I22] has been synthesized solvothermally by reacting BiI3, Zn(NO3)2·6H2O and 4,5-diazafluoren-9-one in a water/ethanol solvent mixture. The asymmetric unit of the compound contains two independent [N-ethyl-4,5-dafo]+ cations and one-half of a centrosymmetric [Bi6I22]4- anion. The average terminal Bi-I, Bi-2-I and Bi-3-I bond lengths in the anion are 2.8923 (2), 3.1403 (2) and 3.3022 (2) Å, respectively.

Alkyne Metathesis With Simple Catalyst Systems: Efficient Synthesis Of Conjugated Polymers Containing Vinyl Groups In Main Or Side Chain, Glen Brizius, Neil Pschirer, Winfried Steffen, Katherine Stitzer, Hans Conrad Zur Loye, Uwe Bunz

Hans Conrad zur Loye

The synthesis of novel conjugated polymers by acyclic diyne metathesis (ADIMET) is reported. These polymers are hybrids between poly(p-phenylenevinylene) and poly(p-phenyleneneethynylene) (PPE). They contain phenylene, ethynylene, and vinylene groups (PhPh, PPVE). Simple in situ catalysts formed from Mo(CO)6 and 4-chlorophenol were used to metathesize the dipropynyl(tetraalkyl)stilbene monomers. The monomers are made by a combination of Horner reactions and Heck-type couplings. The PPVEs form in high yields and are structurally defined. They show degrees of polymerization (Pn) of 30−220 repeating units (i.e. 60−450 benzene rings), demonstrating that the presence of the double bonds does not interfere with alkyne metathesis. The PPVEs …

Euknatao5: Crystal Growth, Structure And Photoluminescence Property, Irina Roof, Mark Smith, Sangmoon Park, Hans Conrad Zur Loye

Hans Conrad zur Loye

The synthesis, structure determination, and intrinsic luminescent properties of a new tantalate, EuKNaTaO5, are reported. Single crystals of the title compound were grown out of a reactive KOH/NaOH eutectic melt. Luminescence in many materials is activated by doping a rare earth cation into the solid matrix; we report undoped, all-rare earth EuKNaTaO5, which exhibits bright orange room temperature photoluminescence.

Tetraquabis(5-Fluorosaccharinato)Nickel(Ii), Larnelle Peterson, Jennifer Kelley, Leroy Peterson, Mark Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

In the centrosymmetric title complex, [Ni(C7H3FNO3S)2(H2O)4], the NiII atom exhibits a slightly distorted trans-NiN2O4 octahedral coordination. The nitrogen donors are provided by two 5-fluorosaccharinate ligands and the oxygen donors are provided by four water molecules. The crystal structure features O-HO and bifurcated O-H(F,O) hydrogen bonds, the latter involving the F atom of the 5-fluorosaccharinate ligand.

Observation Of An Oxygen Isotope Effect In Yba2Cu3O7, Kevin Leary, Hans Conrad Zur Loye, Steven Keller, Tanya Faltens, William Ham, James Michaels, Angelica Stacy

Hans Conrad zur Loye

A small decrease in Tc of 0.3 K to 0.5 K is observed when as much as 90% of the 16O in YBa2Cu3O7 is substituted with18O. This result is consistent with our observation that there is an oxygen isotope effect in La1.85Sr0.15CuO4, but in contrast with previous reports that there is no isotope effect for YBa2Cu3O7. This new result suggests that phonons play an important role in the electron-pairing mechanism in YBa2Cu3O7.

Observation Of An Isotope Shift In The Superconducting Transition Temperature Of La1.85Sr0.15Cuo4, Tanya Faltens, William Ham, Steven Keller, Kevin Leary, James Michaels, Angelica Stacy, Hans Conrad Zur Loye, Donald Morris, T Barbee, Marvin Cohen, Cohen Hoen, A Zettl

Hans Conrad zur Loye

An oxygen isotope shift is observed in superconducting La1.85Sr0.15CuO4 when 18O is substituted partially for 16O; the superconducting transition temperature Tc is lowered by 0.3 to 1.0 K in different samples. We examine these results using conventioanl phonon-mediated BCS theory and conclude that, for La1.85Sr0.15CuO4, phonons play an important role in the pairing mechanism.

Bis[Μ-1,2-Bis(2-Pyridyl)Ethyne-K2N:N']Bis[Aquadinitratocadmium(Ii)], Badruz Zaman, Matthew Davis, Mark Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

Two twisted 1,2-bis(2-pyridyl)ethyne ligands bridge two Cd²⁺ centers in the C₂-symmetric title complex, [Cd₂(NO₃)₄(-C₁₂H₈N₂)₂(H₂O)₂]. The bridging ligands arch across one another creating a `zigzag loop' molecular geometry. Two nitrate ions and a water molecule complete the irregular seven-coordinate Cd-atom environment. The dihedral angles between the equivalent pyridyl ring planes of the two independent ligands are 67.2 (1)°. O_water-HO_nitrate hydrogen bonding creates two-dimensional layers parallel to the ab plane.

Formula: [Cd₂(NO₃)₄(C …

Crystal Growth And Structure Determination Of Novel Barium Rhodates: Stepping Stones Towards 2h-Barho3, Katherine Stitzer, Ahmed Abed, Jacques Darriet, Hans Conrad Zur Loye

Hans Conrad zur Loye

Single crystals of two new barium rhodates were grown from a molten potassium carbonate flux. The new rhodates, Ba₁₁Rh₁₀O₃₀ and Ba₃₂Rh₂₉O₈₇, are structurally related to the 2H-hexagonal perovskite structure and are characterized by pseudo one-dimensional chains of alternating face-sharing trigonal prisms and octahedra. The structures of Ba₁₁Rh₁₀O₃₀ and Ba₃₂Rh₂₉O₈₇ were solved using the 4D superspace group approach in Jana2000. Ba₁₁Rh₁₀O₃₀, with a repeat of nine RhO₆ octahedra followed by one RhO_{6 …}

Trisodium Dicalcium Bismuth Hexaoxide, Irina Puzdrjakova, Rene Macquart, Mark Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

Single crystals of the title compound, Na3Ca2BiO6, were grown from a high-temperature reactive flux solution of Na2CO3. Na3Ca2BiO6 crystallizes as an ordered rock-salt structure (space group Fddd), in which the octahedral holes in the oxide array are filled by an ordered 3:2:1 arrangement of Na+, Ca2+ and Bi5+ cations. All atoms except for one O atom lie on special positions; site symmetries are as follows: Bi 222, Ca 2, Na 222 and 2, O 2.

Tetraaquabis(3-Fluoropyridine-4-Carboxylato-Κn)Zinc(Ii) Dihydrate, Jonetha Fleming, Jennifer Kelley, Leroy Peterson, Mark Smith, Hans Conrad Zur Loye

Hans Conrad zur Loye

In the title compound, [Zn(C₆H₃FNO₂)₂(H₂O)₄]·2H₂O, the Zn^II atom is octahedrally coordinated in a ZnO₄N₂ environment by two 3-fluoropyridine-4-carboxylate (3-fpy4-cbx) ligands and four water molecules. The [Zn(3-fpy4-cbx)₂(H₂O)₄] molecules form a three-dimensional network through strong O-HO and weak O-HF hydrogen bonds between 3-fpy4-cbx and water molecules. The crystal used for data collection was a twin, with the twin law corresponding to a 180° rotation about the real-space [001] axis. The major twin fraction refined to 0.795 (1).

Catena-Poly[[Diaquadinitratozinc(Ii)]Bis(Μ-1,4-Di-3-Pyridyl-2,3-Diaza-1,3-Butadiene)], Shakoya Paulin, Pierre Kelly, Kenneth Williams, Andrea Goforth, Mark Smith, Leroy Peterson, Hans Conrad Zur Loye

Hans Conrad zur Loye

The polymeric title complex, [Zn(NO3)2(C24H20N8)(H2O)2]n, features distorted ZnN2O4 octahedra with each ZnII atom being located on an inversion center. Adjacent Zn ions are doubly bridged by two equivalent 1,4-di-3-pyridyl-2,3-diaza-1,3-butadiene ligands to form linear chains.

Absence Of The Metal-Support Interaction For Ni/Tio2 Composites Prepared Using Ion-Exchange Techniques, Hans Conrad Zur Loye, Tanya Faltens, Angelica Stacy

Hans Conrad zur Loye

Many recent reports on the surface properties of transition-metalcatalysts dispersed on high surface area oxide supports have shown that the support can alter markedly the intrinsic activity of the metal. In particular, when group 8-10 metals are supported on reducible metal oxides, the surface chemistry and the electronic properties of the composite depend on the reduction temperature used for pretreatment. For example, the chemisorption of H2 at room temperature on metal-TiO2 composites decreases sharply as the reduction temperature used to prepare the catalyst is increased from 573 to 773 K. This change in surface chemistryhas been attributed to a strong …

Novel Mixed-Valent (V/Vi) Triple Perovskite Ruthenates: Observation Of A Complex Low Temperature Structural And Magnetic Transition, Katherine Stitzer, Mark Smith, William Gemmill, Hans Conrad Zur Loye

Hans Conrad zur Loye

Two new mixed-valent triple perovskites, Ba3MRu2O9 (M = Li, Na), were grown from reactive hydroxide fluxes. They crystallize in the hexagonal space group P63/mmc, where Ru(V) and Ru(VI) are disordered on only one crystallographic site. Upon cooling, single crystals of Ba3NaRu2O9 undergo a complex symmetry-breaking structural transition at ca. 225 K from room-temperature hexagonal symmetry to a low-temperature orthorhombic symmetry, space group Cmcm. Accompanying this structural transition is a rather abrupt decrease in the magnetic susceptibility at 210 K followed by a steady decrease in the susceptibility with decreasing temperature. Interestingly, the lithium analogue does not display any structural transition …

Structure Determination Of Two New Incommensurate Compounds, Ba1+X[(CuXRh1-X)O3], With X = 0.1605 And X = 0.1695, Using A General Method Based On The Superspacegroup Approach, Mirvat Zakhour-Nakhl, John Claridge, Jacques Darriet, Francois Weill, Hans Conrad Zur Loye, Juan Perez-Mato

Hans Conrad zur Loye

The single-crystal structures of two incommensurate compounds, Ba1+x[(CuxRh1-x)O3] with x = 0.1605 and x = 0.1695, were solved by a general method using the superspace group approach. A saw-tooth function was used to model both the occupational and displacive modulations. This approach requires very few refineable parameters and leads to low residuals, R = 0.0370 and R = 0.0330 for x = 0.1605 and x = 0.1695, respectively. The idealized structures of these two compounds consist of [(CuxRh1-x)O3]∞ chains containing groups of five face-shared (RhO6) octahedra separated by (CuO6) trigonal prisms. These chains in turn are separated from each other …

Poly[Μ2-Nitrato-(Μ4-Pyrazine-2-Carboxylato)Disilver(I)], Kathryn Seward, Joseph Ellsworth, Zeeshan Khaliq, Hans Conrad Zur Loye

Hans Conrad zur Loye

The title compound, [Ag2(C5H3N2O2)(NO3)]n, is a three-dimensional coordination polymer containing two-dimensional slabs held together by bridging nitrate groups. AgNO4 and AgNO5 silver coordination polyhedra arise. Weak argentophilic interactions [AgAg = 3.0686 (7) Å] occur in the crystal structure.