Physical Sciences and Mathematics Commons^™

Data From: All-Metal Σ-Antiaromaticity In Dimeric Cluster Anion {[Cuge9mes]2}4−, Alexander I. Boldyrev, Nikolay Tkachenko

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In this work, we report a dimeric cluster anion, {[CuGe9Mes]2}4−, which was isolated as the [K(2,2,2-crypt)]+ salt and characterized by using single-crystal X-ray diffraction and ESI mass spectroscopy. The title cluster represents the first locally σ-antiaromatic compound in the solid state, as well as the first heteroatomic antiaromatic compound.

Data From: Structure And Bonding In [Sb@In8sb12]3− And [Sb@In8sb12]5−, Alexander I. Boldyrev, Nikolay Tkachenko

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We report the characterization of the compound [K([2.2.2]crypt)]4[In8Sb13], which proves to contain a 1:1 mixture of [Sb@In8Sb12]3− and [Sb@In8Sb12]5−. The tri-anion displays perfect Th symmetry, the first completely inorganic molecule to do so, and contains eight equivalent In3+ centers in a cube. The gas-phase potential energy surface of the penta-anion has eight equivalent minima where the extra pair of electrons is localized on one In+ center, and these minima are linked by low-lying transition states where the electron pair is delocalized over two adjacent centers. The best fit to the electron density is obtained from a model where the structure …

New Ideas From An Old Concept: The Hydrogen Bond, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Ongoing studies of the hydrogen bond (HB), in which a hydrogen (H) atom acts as a bridge between a pair of chemical groups, continues to offer new ideas about this interaction that have applications to biochemical processes. The ability of a proton to transfer within a HB can be controlled by conformational changes that cause small alterations to the HB geometry. The CH group, widely prevalent in biological systems, participates in HBs and contributes to the structure and stability of commonly occurring protein secondary structures such as the β-sheet. The concept of the HB has been extended to systems where …

Intramoleculer Hydrogen Bonding In Epoxide, Thiirane, Aziridine And Phosphirane Containing Cyclopentanols, Ben Edward Smith

Electronic Theses and Dissertations

A recent computational analysis of the stabilizing intramolecular OH· · · O contact in 1,2-dialkyl-2,3-epoxycyclopentanol diastereomers has been extended to thiiriane, aziridine and phosphirane analogues. Density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2) and CCSD(T) coupled-cluster computations with simple methyl and ethyl substituents indicate that electronic energies of the cis isomers are lowered by roughly 3 to 4 kcal mol−1 when the OH group of these cyclopentanol systems forms an intramolecular contact with the O, S, N or P atom on the adjacent carbon. The results also suggest that S and P can participate in these stabilizing intramolecular interactions …

Analysis Of An Adhesion Promoter For Rubber To Metal Bonding, Killian Barton

Doctoral

The intermolecular and intramolecular changes induced by thermal stress in an industrial rubber to metal coupling agent (the ‘green molecule’ or GM) are the subject of this thesis. The GM was analysed in-situ in a model application environment using vibrational spectroscopy. NMR spectroscopy was used in order to analyse the solution chemistry of the compound and how this changed as a result of thermal stress. The interaction of the GM and the substrate was analysed using a range of surface analysis techniques including XPS, AFMIR and EDX. An example of a complex substrate, the zinc phosphate conversion coating, was analysed …

Significant Enhancement Of The Cycling Performance And Rate Capability Of The P/C Composite Via Chemical Bonding (P-C), Weijie Li, Shulei Chou, Jiazhao Wang, Hua-Kun Liu, S X. Dou

Australian Institute for Innovative Materials - Papers

Among anode materials for sodium ion batteries, red phosphorus is a very promising one due to its abundant reserves, low-cost and high theoretical capacity of 2600 mA h g-1. However, its huge volume expansion on sodiation (∼490%) and poor conductivity leads to dramatic capacity decay, restraining its practical application. To improve the electrochemical performance, here, we prepared a red phosphorus and graphene nanoplate composite using cheap red P and natural graphite as the starting materials via a simple and scalable ball-milling method. The phosphorus-carbon bond formed during the milling process improves the electrical connectivity between P particles and graphene nanoplates, …

One-Step Bonding Of Ni Electrode To N-Type Pbte - A Step Towards Fabrication Of Thermoelectric Generators, Xavier Reales Ferreres, Sima Aminorroaya-Yamini, Mitchell John Bromley Nancarrow, C Zhang

Australian Institute for Innovative Materials - Papers

PbTe-based thermoelectric materials are good candidates for harvesting waste heat at mid-range temperatures due to their high thermoelectric efficiencies. Excellent quality and reliability of the bonding between the thermoelectric material and the electrode at high temperatures are essential for manufacturing thermoelectric generators. Here, a technique has been developed to achieve high-quality bonding between PbTe and the electrode. We have successfully performed one-step sintering of nickel electrode to n-type PbTe powder using spark plasma sintering. The fabricated interphase, composed of nickel telluride, is continuous and homogeneous across the junction, without visible flaws on the electrode or in the interphase and PbTe. …

Ultrasonic Bonding For The Cuore Collaboration, John J. Sekerak Ii

Physics

This paper will give the reader a brief introduction to the Standard Model, Neutrinoless Double Beta Decay, and the CUORE experiment under construction at Gran Sasso National Lab in Assergi, Italy. The remainder of the paper will describe the bonding process used to connect the heater pads and NTDs to the copper housings of the tower structure. Extensive details of the troubleshooting and calibration period are presented as a way for the reader to better understand the concepts involved during the bonding stage of the assembly process.

Iridium-Ruthenium/Osmium-Gold Cluster Complexes: Unique Structures And Properties, Qiang Zhang

Theses and Dissertations

Chapter Two

The first Ir-Ru cluster complex was synthesized was the electron-rich, anionic, planar cluster complex [PPN][IrRu6(CO)23], 2.5, (PPN=Bis(triphenylphophoranylidene)-ammonium) which obtained from the reaction of [PPN][IrRu3(CO)13] with one equivalent ruthenium carbonyl (Ru3(CO)12) at 66 oC (THF reflux) for 12h. Compound 2.5 could also be synthesized by using the mono-Iridium compound [PPN][Ir(CO)4] reacts with two equivalent of ruthenium carbonyl. In compound 2.5, all seven metal atoms lie in a plane (max deviation = 0.043(1) Å) with the iridium atom in the center circumscribed by a hexagonal ring of six ruthenium atoms. The anion 2.5 contains 104 valence electrons while both the …

Bonding Over Bushfires: Social Networks In Action, Mark Freeman, Alison Freeman

Dr Mark Freeman

A world-first nation-wide community website scheme was established in Australia in 2006 to enhance existing, and build new, social networks within geographic communities. By doing so, it sought to promote geographic community engagement. Initially, this paper presents an overview of the scheme since its inception and review the current geographic community groups participating in the scheme. To date the scheme has had limited success in attracting a critical mass of communities that value the promoted benefits of social networks in this format, with only 154 community websites across Australia. While it has not achieved the expected level of uptake, the …

Slides: Collaborative Planning And Lessons Learned, Matt Sura

Best Management Practices (BMPs): What? How? And Why? (May 26)

Presenter: Matt Sura, University of Colorado Law School

48 slides

Chitosan Adhesive Films For Photochemical Tissue Bonding, Antonio Lauto, Damia Mawad, Matthew Barton, Sabine C. Piller, Leonardo Longo

Australian Institute for Innovative Materials - Papers

Photochemical tissue bonding (PTB) is a promising sutureless technique for tissue repair. PTB is often achieved by applying a solution of rose bengal (RB) between two tissue edges, which are irradiated by a green laser to crosslink collagen fibers with minimal heat production. In this study, RB has been incorporated in chitosan films to create a novel tissue adhesive that is laser-activated. Materials and Methods. Adhesive films, based on chitosan and containing ∼0.1wt% RB were manufactured and bonded to calf intestine by a solid state laser (wavelength =532nm, Fluence ∼110J/cm2, spot size ∼5 mm). A single-column tensiometer, interfaced with a …

Inter­Molecular Di­Hydrogen- And Hydrogen-Bonding Inter­Actions In Di­Ammonium Closo-Deca­Hydro­Deca­Borate Sesquihydrate, Teshome B. Yisgedu, Xuenian Chen, Hima Kumar Lingam, Zhenguo Huang, Edward A. Meyers, Sheldon G. Shore, Ji-Cheng Zhao

Australian Institute for Innovative Materials - Papers

The asymmetric unit of the title salt, 2NH4+_B10H102__1.5H2O or (NH4)2B10H10_1.5H2O, (I), contains two B10H102_ anions, four NH4+ cations and three water molecules. (I) was converted to the anhydrous compound (NH4)2B10H10, (II), by heating to 343 K and its X-ray powder pattern was obtained. The extended structure of (I) shows two types of hydrogen-bonding interactions (N-H_ _ _O and O-H_ _ _O) and two types of dihydrogen-bonding interactions (N- H_ _ _H-B and O-H_ _ _H-B). The N-H_ _ _H-B dihydrogen bonding forms a two-dimensional sheet structure, and hydrogen bonding (N-H_ _ _O and O-H_ _ _O) and O- H_ _ …

Bonding Over Bushfires: Social Networks In Action, Mark Freeman, Alison Freeman

Faculty of Informatics - Papers (Archive)

A world-first nation-wide community website scheme was established in Australia in 2006 to enhance existing, and build new, social networks within geographic communities. By doing so, it sought to promote geographic community engagement. Initially, this paper presents an overview of the scheme since its inception and review the current geographic community groups participating in the scheme. To date the scheme has had limited success in attracting a critical mass of communities that value the promoted benefits of social networks in this format, with only 154 community websites across Australia. While it has not achieved the expected level of uptake, the …

Photochemical Tissue Bonding With Chitosan Adhesive Films, A Lauto, Damia Mawad, Matthew Barton, Abhishek Gupta, Sabine Piller, James Hook

Faculty of Science - Papers (Archive)

Background: Photochemical tissue bonding (PTB) is a promising sutureless technique for tissue repair. PTB is often achieved by applying a solution of rose bengal (RB) between two tissue edges, which are irradiated by a green laser to crosslink collagen fibers with minimal heat production. In this study, RB has been incorporated in chitosan films to create a novel tissue adhesive that is laser-activated. Methods: Adhesive films, based on chitosan and containing ~0.1 wt% RB were manufactured and bonded to calf intestine by a solid state laser (l = 532 nm, Fluence~110 J/cm2, spot size~0.5 cm). A single-column tensiometer, interfaced with …

Pentadienyl Complexes Of Alkali Metals: Structure And Bonding, Erick Cerpa, Francisco J. Tenorio, Maryel Contreras, Manuel Villanueva, Hiram I. Beltran, Thomas Heine, Kelling J. Donald, Gabriel Merino

Chemistry Faculty Publications

A systematic density functional study of the structure and bonding in the alkali-metal pentadienyl complexes C₅H₇E (E = Li-Cs) and their analogues derived from the 2,4-dimethylpentadienyl ligand is performed. The bonding in these structures has been analyzed in some detail with reference to molecular orbital analysis, and energy partition analysis, obtained by density functional calculations. An energy decomposition analysis indicates that the electrostatic interaction is the main factor to be considered in the stabilization of the gas-phase complexes we have studied. The stability of the U-shaped minimum energy structure decreases (the potential energy surface becomes more …

A Novel Empirical Free Energy Function That Explains And Predicts Protein–Protein Binding Affinities, Joseph Audie, Suzanne Scarlata

Chemistry & Physics Faculty Publications

A free energy function can be defined as a mathematical expression that relates macroscopic free energy changes to microscopic or molecular properties. Free energy functions can be used to explain and predict the affinity of a ligand for a protein and to score and discriminate between native and non-native binding modes. However, there is a natural tension between developing a function fast enough to solve the scoring problem but rigorous enough to explain and predict binding affinities. Here, we present a novel, physics-based free energy function that is computationally inexpensive, yet explanatory and predictive. The function results from a derivation …

Synthesis, Characterization, And Spectroscopy Of Model Molybdopterin Complexes, Sharon J. Nieter Burgmayer, Mary Kim, Rebecca Petit, Amy Rothkopf, Shadia Belhamdounia, Ying Hou, Arpad Somogyi, Diana Habel-Rodriguez, Antonio Williams, Martin L. Kirk

Chemistry Faculty Research and Scholarship

The preparation and characterization of new model complexes for the molybdenum cofactor are reported. The new models are distinctive for the inclusion of pterin-substituted dithiolene chelates and have the formulation Tp*MoX(pterin-R-dithiolene) (Tp* = tris(3,5,-dimethylpyrazolyl)borate), X= O, S, R= aryl or –C(OH)(CH₃)₂). Syntheses of Mo(4+) and (5+) complexes of two pterin-dithiolene derivatives as both oxo and sulfido compounds, and improved syntheses for pterinyl alkynes and [Et₄N][Tp*Mo^IV(S)S₄] reagents are described. Characterization methods include electrospray ionization mass spectrometry, electrochemistry, infrared spectroscopy, electron paramagnetic resonance and magnetic circular dichroism. Cyclic voltammetry reveals that the …

Two Different Modes Of Halogen Bonding In Two 4-Nitroimidazole Derivatives, Maciej Kubicki, Pawel Wagner

Australian Institute for Innovative Materials - Papers

In the crystal structures of the two imidazole derivatives 5-chloro-1,2-dimethyl-4-nitro-1H-imidazole, C₅H₆ClN₃O₂, (I), and 2-chloro-1-methyl-4-nitro-1H-imidazole, C₄H₄ClN₃O₂, (II), C—Cl...O halogen bonds are the principal specific interactions responsible for the crystal packing. Two different halogen-bond modes are observed: in (I), there is one very short and directional C—Cl...O contact [Cl...O = 2.899 (1) Å], while in (II), the C—Cl group approaches two different O atoms from two different molecules, and the contacts are longer [3.285 (2) and 3.498 (2) Å] and less directional. …

Electronic Structure And Bonding In Metal Porphyrins, Metal=Fe, Co, Ni, Cu, Zn, M.-S. Liao, Steve Scheiner

Steve Scheiner

A systematic theoretical study of the electronic structure and bonding in metal meso-tetraphenyl porphines MTPP, M=Fe, Co, Ni, Cu, Zn has been carried out using a density functional theory method. The calculations provide a clear elucidation of the ground states for the MTPPs and for a series of [MTPP]^x ions (x = 2+, 1+, 1−, 2−, 3−, 4−), which aids in understanding a number of observed electronic properties. The calculation supports the experimental assignment of unligated FeTPP as ³A_2g, which arises from the configuration (d_xy)²(d_{z …}

Electronic Structure And Bonding In Unligated And Ligated Feii Porphyrins, M.-S. Liao, Steve Scheiner

Steve Scheiner

The electronic structure and bonding in a series of unligated and ligated Fe^II porphyrins (FeP) are investigated by density functional theory (DFT). All the unligated four-coordinate iron porphyrins have a ³A_2g ground state that arises from the (d_xy)²(d_z²)²(d_π)² configuration. The calculations confirm experimental results on Fe tetraphenylporphine but do not support the resonance Raman assignment of Fe octaethylporphine as ³E_g, nor the early assignment of Fe octamethyltetrabenzporphine as ⁵B_2g. For the six-coordinate Fe–P( …

Electronic Structure And Bonding In Metal Porphyrins, Metal=Fe, Co, Ni, Cu, Zn, M.-S. Liao, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

A systematic theoretical study of the electronic structure and bonding in metal meso-tetraphenyl porphines MTPP, M=Fe, Co, Ni, Cu, Zn has been carried out using a density functional theory method. The calculations provide a clear elucidation of the ground states for the MTPPs and for a series of [MTPP]^x ions (x = 2+, 1+, 1−, 2−, 3−, 4−), which aids in understanding a number of observed electronic properties. The calculation supports the experimental assignment of unligated FeTPP as ³A_2g, which arises from the configuration (d_xy)²(d_{z …}

Electronic Structure And Bonding In Unligated And Ligated Feii Porphyrins, M.-S. Liao, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The electronic structure and bonding in a series of unligated and ligated Fe^II porphyrins (FeP) are investigated by density functional theory (DFT). All the unligated four-coordinate iron porphyrins have a ³A_2g ground state that arises from the (d_xy)²(d_z²)²(d_π)² configuration. The calculations confirm experimental results on Fe tetraphenylporphine but do not support the resonance Raman assignment of Fe octaethylporphine as ³E_g, nor the early assignment of Fe octamethyltetrabenzporphine as ⁵B_2g. For the six-coordinate Fe–P( …

Electronic Structure And Bonding In Metal Phthalocyanines, Metal=Fe, Co, Ni, Cu, Zn, Mg, M.-S. Liao, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Electronic structure and bonding in metal phthalocyanines (Metal=Fe, Co, Ni, Cu, Zn, Mg) is investigated in detail using a density functional method. The metal atoms are strongly bound to the phthalocyanine ring in each case, by as much as 10 eV. The calculated orbital energy levels and relative total energies of these D_4h structures indicate that Fe and Co phthalocyanines have ³A_2g and ²E_g ground states, respectively, but that these states are changed upon interaction with strong-field axial ligands. The valence electronic structures of Fe and Co phthalocyanines differ significantly from those of …

Alkali Oxides. Analysis Of Bonding And Explanation Of The Reversal Of Ordering Of The 2Σ And 2Π States, Janet N. Allison, Robert J. Cave, William A. Goddard Iii

All HMC Faculty Publications and Research

We analyze the bonding in alkali oxides, MO, for M = Li, Na, K, Rb, and Cs. Using ab initio correlated wave functions we find that the ground state is ²II for M = Li, Na, and K and that the ground state is ²Ʃ^+ for M = Rb and Cs. The origin of this effect is explained.