Life Sciences Commons^™

Photophysical And Optical Properties Of Semiconducting Polymer Nanoparticles Prepared From Hyaluronic Acid And Polysorbate 80, Adam Langlois, Gage T. Mason, Michael H.L. Nguyen, Mehdi Rezapour, Paul Ludovic Karsenti, Drew Marquardt, Simon Rondeau-Gagné

Chemistry and Biochemistry Publications

Copyright © 2019 American Chemical Society. A nanoprecipitation procedure was utilized to prepare novel diketopyrrolopyrrole-based semiconducting polymer nanoparticles (SPNs) with hyaluronic acid (HA) and polysorbate 80. The nanoprecipitation led to the formation of spherical nanoparticles with average diameters ranging from 100 to 200 nm, and a careful control over the structure of the parent conjugated polymers was performed to probe the influence of π-conjugation on the final photophysical and thermal stability of the resulting SPNs. Upon generation of a series of novel SPNs, the optical and photophysical properties of the new nanomaterials were probed in solution using various techniques including …

Oh Chemistry Of Non-Methane Organic Gases (Nmogs) Emitted From Laboratory And Ambient Biomass Burning Smoke: Evaluating The Influence Of Furans And Oxygenated Aromatics On Ozone And Secondary Nmog Formation, Matthew M. Coggon, Christopher Y. Lim, Abigail R. Koss, Kanako Sekimoto, Bin Yuan, Jessica B. Gilman, David H. Hagan, Vanessa Selimovic, Kyle J. Zarzana, Steven S. Brown, James M Roberts, Markus Müller, Robert Yokelson, Armin Wisthaler, Jordan E. Krechmer, Jose L. Jimenez, Christopher Cappa, Jesse H. Kroll, Joost De Gouw, Carsten Warneke

Chemistry and Biochemistry Faculty Publications

Chamber oxidation experiments conducted at the Fire Sciences Laboratory in 2016 are evaluated to identify important chemical processes contributing to the hydroxy radical (OH) chemistry of biomass burning non-methane organic gases (NMOGs). Based on the decay of primary carbon measured by proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS), it is confirmed that furans and oxygenated aromatics are among the NMOGs emitted from western United States fuel types with the highest reactivities towards OH. The oxidation processes and formation of secondary NMOG masses measured by PTR-ToF-MS and iodide-clustering time-of-flight chemical ionization mass spectrometry (I-CIMS) is interpreted using a box model employing …

Isotopic Characterization Of Nitrogen Oxides (NoX), Nitrous Acid (Hono), And Nitrate (PNo3-) From Laboratory Biomass Burning During Firex, Jiajue Chai, David J. Miller, Eric Scheuer, Jack Dibb, Vanessa Selimovic, Robert Yokelson, Kyle K. Zarzana, Steven Brown, Abigail R. Koss, Carsten Warneke, Meredith Hastings

Chemistry and Biochemistry Faculty Publications

New techniques have recently been developed and applied to capture reactive nitrogen species, including nitrogen oxides (NOx D NOCNO2), nitrous acid (HONO), nitric acid (HNO3), and particulate nitrate (pNO3 ), for accurate measurement of their isotopic composition. Here, we report – for the first time – the isotopic composition of HONO from biomass burning (BB) emissions collected during the Fire Influence on Regional to Global Environments Experiment (FIREX, later evolved into FIREX-AQ) at the Missoula Fire Science Laboratory in the fall of 2016. We used our newly developed annular denuder system (ADS), which was verified to completely capture HONO associated …

Covalently Functionalized Sawdust For The Remediation Of Phosphate From Agricultural Wastewater, Daniel Meister, David Ure, Angela Awada, Jean-Claude Barrette, Joel Gagnon, Bluent Mutus, John F. Trant

Chemistry and Biochemistry Publications

Phosphate remediation from wastewater is rapidly becoming an ever more attractive process due to a combination of both the economic pressure of increasing phosphate scarcity and the environmental damage caused by untreated agricultural runoff. Ideally, remediated phosphate will be recoverable and would be able to be reused as fertilizer. Many different resins have been investigated, but due to the scale of the challenge, any feasible solution will involve the use of very inexpensive waste products as the solid support. Sawdust, functionalized with iron-binding ligands, is such a potential resin. Sawdust alone binds 0.3 g/kg of phosphate which is insufficient. Iron …

Salty Sensors, Fresh Ideas: The Use Of Molecular And Imaging Sensors In Understanding Plankton Dynamics Across Marine And Freshwater Ecosystems, Trisha Lyn Spanbauer, Christian Briseno-Avena, Kathleen Johnson Pitz, Elizabeth A. Suter

Faculty Works: Biology, Chemistry, and Environmental Studies

Understanding plankton dynamics in marine ecosystems has been advanced using in situ molecular and imaging instrumentation. A range of research objectives have been addressed through high‐resolution autonomous sampling, from food web characterization to harmful algal bloom dynamics. When used together, molecular and imaging sensors can cover the full‐size range, genetic identity, and life stages of plankton. Here, we briefly review a selection of in situ instrumentation developed for the collection of molecular and imaging information on plankton communities in marine ecosystems. In addition, we interviewed a selection of instrumentation developers to determine if the transfer of sensor technology from marine …

Aerial And Ground-Based Optical Gas Imaging Survey Of Uinta Basin Oil And Gas Wells, Seth N. Lyman, Trang Tran, Marc L. Mansfield, Arvind P. Ravikumar

Bingham Research Center

We deployed a helicopter with an infrared optical gas imaging camera to detect hydrocarbon emissions from 3,428 oil and gas facilities (including 3,225 producing oil and gas well pads) in Utah’s Uinta Basin during winter and spring 2018. We also surveyed 419 of the same well pads from the ground. Winter conditions led to poor contrast between emission plumes and the ground, leading to a detection limit for the aerial survey that was between two and six times worse than a previous summertime survey. Because the ground survey was able to use the camera’s high-sensitivity mode, the rate of detected …

The Total Syntheses Of Jbir-94 And Two Synthetic Analogs And Their Cytotoxicities Against A549 (Ccl-185) Human Small Lung Cancer Cells, Cathy L. Mangum, Mica B. Munford, Alyssa Sam, Sandra K. Young, Jeremy T. Beales, Yagya Prasad Subedi, Chad D. Mangum, Tanner J. Allen, Miranda S. Liddell, Andrew I. Merrell, Diana I. Saavedra, Becky L. Williams, Nicole Evans, Joseph L. Beales, Mike A. Christiansen

Chemistry and Biochemistry Faculty Publications

We here disclose the total syntheses of the natural polyphenol JBIR-94 and two nonnatural analogs, whose structures are of interest for their bioactivity potential as radical scavengers. Although we initially attempted this by dually acylating both of putrecine’s amine nitrogens in a single pot, our endeavors with this method (which has been successfully reported by other groups) proved ineffectual. We accordingly opted for the lengthier approach of acylating each amine individually, which gratuitously prevailed and also aligns with separate literature precedent. Moreover, we here share our analysis of these target compounds’ cytotoxicities and IC₅₀ values against A549 (CCL-185) human …

How Oxygen Availability Affects The Antimicrobial Efficacy Of Host Defense Peptides: Lessons Learned From Studying The Copper-Binding Peptides Piscidins 1 And 3, Adenrele Oludiran, David S. Courson, Malia D. Stuart, Anwar R. Radwan, John C. Putsma, Myriam L. Cotten, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The development of new therapeutic options against Clostridioides difficile (C. difficile) infection is a critical public health concern, as the causative bacterium is highly resistant to multiple classes of antibiotics. Antimicrobial host-defense peptides (HDPs) are highly effective at simultaneously modulating the immune system function and directly killing bacteria through membrane disruption and oxidative damage. The copper-binding HDPs piscidin 1 and piscidin 3 have previously shown potent antimicrobial activity against a number of Gram-negative and Gram-positive bacterial species but have never been investigated in an anaerobic environment. Synergy between piscidins and metal ions increases bacterial killing aerobically. Here, we …

Fate Of The Organophosphate Insecticide, Chlorpyrifos, In Leaves, Soil, And Air Following Application, Supta Das, Kimberly J. Hageman, Madeleine Taylor, Sue Michelsen-Heath, Ian Stewart

Chemistry and Biochemistry Faculty Publications

A field study was conducted to further our understanding about the fate and transport of the organophosphate insecticide, chlorpyrifos, and its degradation product, chlorpyrifos oxon. Leaf, soil and air sampling was conducted for 21 days after chlorpyrifos application to a field of purple tansy (Phacelia tanacetifolia). Air samples were collected using a high-volume air sampler (HVAS) and seven battery-operated medium-volume active air samplers placed around the field and on a 500-m transect extending away from the field. Chlorpyrifos was detected every day of the sampling period in all matrices, with concentrations decreasing rapidly after application. Chlorpyrifos oxon was …

Biochar Enhances Nitrous Oxide Reduction In Acidic But Not In Near-Neutral Ph Soil, Engil Isadora Pujol Pereira, Jerome Lechot, Rafaela Feola Conz, Abmael Da Silva Cardoso, Johan Six

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

We quantified nitrous oxide (N2O) fluxes and total denitrification (N2O + N2) in an acidic (Ferralsol) and a near-neutral pH soil (Cambisol) to determine whether biochar’s alkalinization effect could be the mechanism inducing potential reductions in N2O fluxes. In Ferralsol, decreases in N2O emissions and in the N2O to N2O + N2 ratio were observed in both biochar and lime treatments. In Cambisol, neither biochar nor lime decreased N2O emissions, despite significantly increasing soil pH. The abundance and community structure of nosZ gene-bearing microorganisms indicated that gene abundances did not explain biochar effects, but a higher diversity of nosZ gene-bearing …

Changes In Pm2.5 Peat Combustion Source Profiles With Atmospheric Aging In An Oxidation Flow Reactor, Judith C. Chow, Junji Cao, Lung-Wen Anthony Chen, Xiaoliang Wang, Qiyuan Wang, Jie Tian, Steven Sai Hang Ho, Adam C. Watts, Tessa B. Carlson, Steven D. Kohl, John G. Watson

Environmental & Occupational Health Faculty Publications

Smoke from laboratory chamber burning of peat fuels from Russia, Siberia, the USA (Alaska and Florida), and Malaysia representing boreal, temperate, subtropical, and tropical regions was sampled before and after passing through a potential-aerosol-mass oxidation flow reactor (PAM-OFR) to simulate intermediately aged (∼2 d) and well-aged (∼7 d) source profiles. Species abundances in PM2.5 between aged and fresh profiles varied by several orders of magnitude with two distinguishable clusters, centered around 0.1 % for reactive and ionic species and centered around 10 % for carbon. Organic carbon (OC) accounted for 58 %–85 % of PM2.5 mass in fresh profiles with …

Opening Of An Epoxide Ring Using Azide To Form A Triazole, Emily Hufnagel, Jeffrey A. Hansen

Annual Student Research Poster Session

No abstract provided.

Synthesis Of Ether Alcohols With Varying Catalysts, Hannah Grady, Frida Li, Jeffrey A. Hansen

Annual Student Research Poster Session

No abstract provided.

Microwave Solventless Synthesis Of Meso-Tetrakis (Pentafluorophenyl)Poprphyrin (Tppf20) And Tris(Pentafluorophenyl))Corrole [Chemistry], Sunaina Singh

Open Educational Resources

Organic chemistry is a two-semester course (Organic Chemistry I, SCC 251 and Organic Chemistry II, SCC 252) required for majors in Biology. The SCC 251 course has been designated for the Integrative Learning Core Competency as well the Digital Communication Ability. This course emphasizes the synthesis, structure, reactivity, and mechanisms of reaction of organic compounds. Laboratory stresses various organic synthetic and analytic techniques (distillation, extraction, chromatography and spectroscopy).

This lab provided an opportunity for students to go deeper with the chemistry content by correlating to the concepts they learned in General Chemistry courses such as Valence shell electron pair repulsion …

Titration Of A Newtown Creek Environmental Water Sample To Determine The Amount Of Chloride Ions [Chemistry], Kevin Mark

Open Educational Resources

Main Course Learning Objectives:

The General Chemistry 1 (SCC 201) course has multiple course learning objectives, which articulate key introductory chemistry concepts that all STEM students should possess. In particular, the Newtown Creek titration experiment aligns with SCC 201 learning objectives of:

1. Demonstrate an appreciation of the role of chemistry in various aspects of life
2. Perform basic laboratory skills such as the proper execution of titration techniques
3. Describe and explain the fundamental chemistry concept of solution concentration
4. Analyze and represent experimental data in tables and graphs, interpret experimental results and write laboratory reports

In the SCC 201 laboratory, students are …

Leaving Ligand Effects On Reactivity And Solubility Of Monofunctional Platinum(Ii) Anticancer Complexes, Heidi Linn Hruska Millay

Masters Theses & Specialist Projects

Monofunctional platinum(II) complexes, such as phenanthriplatin and pyriplatin, have notably different characteristics from the bifunctional anticancer complexes, such as cisplatin and oxaliplatin, which have detrimental toxicities and resistance associated with them. The unique properties of the monofunctional complexes may be exploited to target cancer cells without producing the toxic side effects associated with the current FDA-approved platinum-based anticancer drugs. To advance the understanding of these monofunctional platinum(II) complexes, this study replaced the chloride leaving ligand with an acetate group, which should increase solubility and alter the rate of reactivity with key amino acid and nucleotide targets. Phenanthriplatin and pyriplatin compounds …

Data From: Cavitation Clusters In Lipid Systems – The Generation Of A Bifurcated Streamer And The Dual Collapse Of A Bubble Cluster, Silvana Martini, Peter Birkin, Tadd T. Truscott

Browse all Datasets

Over the past decade several studies have reported the use of high intensity ultrasound (HIU) to induce the crystallization of lipids. The effect that HIU has on lipid crystallization is usually attributed to the generation of cavities but acoustic cavitation has never been fully explored in lipids. The dynamics of a particular cavitation cluster next to a piston like emitter in an oil, was investigated in this study. The lipid systems, which are important in food processing, are studied with high-speed camera imaging, laser scattering and pressure measurements. A sequence of stable clusters were noted. In addition, a bifurcated streamer …

Literature Review: Biocement For Stabilization Of Expansive Soils In Las Vegas, Nevada, Silva Topchyan, Moses Karakouzian

LSAMP Poster Presentations

The aim of this study was to present a possibility for the use of biocementon expansive clay. Expansive soil is a type of clay when exposed to water and moisture changes its volume. Due to the clays swelling and shrinkage behavior itsdifficult to use it in engineering and construction projects, therefore costly and unhealthy techniques have been used to stabiliseexpansive soil in order to address the problem [12]. A possible healthy and environmentally friendly solution is Biocement which uses microbial induced calcite precipitation (MICP) in order to help aggregate soil to form a stable cementitiousmaterial. MICP isdependent on the innate …

9th Annual Postdoctoral Science Symposium, University Of Texas Md Anderson Cancer Center Postdoctoral Association

Annual Postdoctoral Science Symposium Abstracts

The mission of the Annual Postdoctoral Science Symposium (APSS) is to provide a platform for talented postdoctoral fellows throughout the Texas Medical Center to present their work to a wider audience. The MD Anderson Postdoctoral Association convened its inaugural Annual Postdoctoral Science Symposium (APSS) on August 4, 2011.

The APSS provides a professional venue for postdoctoral scientists to develop, clarify, and refine their research as a result of formal reviews and critiques of faculty and other postdoctoral scientists. Additionally, attendees discuss current research on a broad range of subjects while promoting academic interactions and enrichment and developing new collaborations.

Theoretical Studies Of Ir And Nmr Spectral Changes Induced By Sigma-Hole Hydrogen, Halogen, Chalcogen, Pnicogen, And Tetrel Bonds In A Model Protein Environment, Mariusz Michalczyk, Wiktor Zierkiewicz, Rafał Wysokiński, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Various types of σ-hole bond complexes were formed with FX, HFY, H₂FZ, and H₃FT (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) as Lewis acid. In order to examine their interactions with a protein, N-methylacetamide (NMA), a model of the peptide linkage was used as the base. These noncovalent bonds were compared by computational means with H-bonds formed by NMA with XH molecules (X = F, Cl, Br, I). In all cases, the A–F bond, which lies opposite the base and is responsible for …

Peptide-Induced Lipid Flip-Flop In Asymmetric Liposomes Measured By Small Angle Neutron Scattering, Michael H.L. Nguyen, Mitchell Dipasquale, Brett W. Rickeard, Milka Doktorova, Frederick A. Heberle, Haden L. Scott, Francisco N. Barrera, Graham Taylor, Charles P. Collier, Christopher B. Stanley, John Katsaras, Drew Marquardt

Chemistry and Biochemistry Publications

© 2019 American Chemical Society. Despite the prevalence of lipid transbilayer asymmetry in natural plasma membranes, most biomimetic model membranes studied are symmetric. Recent advances have helped to overcome the difficulties in preparing asymmetric liposomes in vitro, allowing for the examination of a larger set of relevant biophysical questions. Here, we investigate the stability of asymmetric bilayers by measuring lipid flip-flop with time-resolved small-angle neutron scattering (SANS). Asymmetric large unilamellar vesicles with inner bilayer leaflets containing predominantly 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and outer leaflets composed mainly of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) displayed slow spontaneous flip-flop at 37 -C (half-time, t1/2 = 140 h). However, …

Nitric Oxide Is Involved In Heavy Ion-Induced Non-Targeted Effects In Human Fibroblasts, Megumi Hada, Premkumar B. Saganti, Francis A. Cucinotta

Health Physics & Diagnostic Sciences Faculty Publications

Previously, we investigated the dose response for chromosomal aberration (CA) for exposures corresponding to less than one particle traversal per cell nucleus by high energy and charge (HZE) particles, and showed that the dose responses for simple exchanges for human fibroblast irradiated under confluent culture conditions were best fit by non-linear models motivated by a non-targeted effect (NTE). Our results suggested that the simple exchanges in normal human fibroblasts have an important NTE contribution at low particle fluence. Nitric oxide (NO) has been reported as a candidate for intercellular signaling for NTE in many studies. In order to estimate the …

Rompi-Cdsa: Ring-Opening Metathesis Polymerization-Induced Crystallization-Driven Self-Assembly Of Metallo-Block Copolymers, Ye Sha, Md Anisur Rahman, Tianyu Zhu, Yujin Cha, C Wayne Mcalister, Chuanbing Tang

Faculty Publications

Polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) are among the most prevailing methods for block copolymer self-assembly. Taking the merits of scalability of PISA and dimension control of CDSA, we report one-pot synchronous PISA and CDSA ring-opening metathesis polymerization (ROMP) to prepare nano-objects based on a crystalline poly(ruthenocene) motif. We denote this self-assembly methodology as ROMPI-CDSA to enable a simple, yet robust approach for the preparation of functional nanomaterials.

Loss Of Scribble Confers Cisplatin Resistance During Nsclc Chemotherapy Via Nox2/Ros And Nrf2/Pd-L1 Signaling, Na Wang, Lele Song, Yi Xu, Longfu Zhang, Yanjun Wu, Jingyu Guo, Weiwei Ji, Li Li Ph.D., Jingya Zhao, Xin Zhang, Lixing Zhan

Faculty Works: Biology, Chemistry, and Environmental Studies

Background: Cisplatin resistance remains a major clinical obstacle to the successful treatment of non-small cell lung cancer (NSCLC). Scribble contributes to ROS-induced inflammation and cisplatin-elevated toxic reactive oxygen species (ROS) promotes cell death. However, it is unknown whether and how Scribble is involved in the cisplatin-related cell death and the underlying mechanism of Scribble in response to chemotherapies and in the process of oxidative stress in NSCLC. Methods: We used two independent cohorts of NSCLC samples derived from patients treated with platinumcontaining chemotherapy and xenograft modeling in vivo. We analyzed the correlation between Scribble and Nox2 or Nrf2/PD-L1 both in …

Anisotropic Singlet Fission In Single Crystalline Hexacene, Dezheng Sun, Gang-Hua Deng, Bolei Xu, Enshi Xu, Xia Li, Yajing Wu, Yuqin Qian, Yu Zhong, Colin Nuckolls, Avetik R. Harutyunyan, Hai-Lung Dai, Gugang Chen, Hanning Chen, Yi Rao

Chemistry and Biochemistry Faculty Publications

Singlet fission is known to improve solar energy utilization by circumventing the Shockley-Queisser limit. The two essential steps of singlet fission are the formation of a correlated triplet pair and its subsequent quantum decoherence. However, the mechanisms of the triplet pair formation and decoherence still remain elusive. Here we examined both essential steps in single crystalline hexacene and discovered remarkable anisotropy of the overall singlet fission rate along different crystal axes. Since the triplet pair formation emerges on the same timescale along both crystal axes, the quantum decoherence is likely responsible for the directional anisotropy. The distinct quantum decoherence rates …

Spectroscopic Description Of The E1 State Of Mo Nitrogenase Based On Mo And Fe X‑Ray Absorption And MöSsbauer Studies, Casey Van Stappen, Roman Davydov, Zhi-Yong Yang, Ruixi Fan, Yisong Guo, Eckhard Bill, Lance C. Seefeldt, Brian M. Hoffman, Serena Debeer

Chemistry and Biochemistry Faculty Publications

Mo nitrogenase (N2ase) utilizes a two-component protein system, the catalytic MoFe and its electron-transfer partner FeP, to reduce atmospheric dinitrogen (N₂) to ammonia (NH₃). The FeMo cofactor contained in the MoFe protein serves as the catalytic center for this reaction and has long inspired model chemistry oriented toward activating N₂. This field of chemistry has relied heavily on the detailed characterization of how Mo N2ase accomplishes this feat. Understanding the reaction mechanism of Mo N2ase itself has presented one of the most challenging problems in bioinorganic chemistry because of the ephemeral nature of its …

Synthesis And Evaluations Of “1,4-Triazolyl Combretacoumarins” And Desmethoxy Analogs, Tashrique A. Khandaker, Jessica D. Hess, Renato Aguilera, Graciela Andrei, Robert Snoeck, Dominique Schols, Padmanava Pradhan, Mahesh K. Lakshman

Publications and Research

1,4-Triazolyl combretacoumarins have been prepared by linking the trimethoxyarene unit of combretastatin A4 with coumarins, via a 1,2,3-triazole. For this, 4-azidocoumarins were accessed by a sequential two-step, one-pot reaction of 4-hydroxycoumarins with (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), followed by reaction with NaN₃. In the reaction with BOP, a coumarin-derived phosphonium ion intermediate seems to form, leading to an O⁴-(benzotriazolyl)coumarin derivative. For the CuAAC reaction of azidocoumarins with 5-ethynyl-1,2,3-trimethoxybenzene, catalytic [(MeCN)₄Cu]PF₆ in CH₂Cl₂/MeOH with 2,6-lutidine, at 50 ^oC, was suitable. The 4-azidocoumarins were less reactive as compared to PhN₃ and …

Neuro And Hepatic Toxicological Profile Of (S)-2,4-Diaminobutanoic Acid In Embryonic, Adolescent And Adult Zebrafish, Rosa-Maria Ferraiuolo, Daniel Meister, Dominique Leckie, Jonathan Franke, Lisa A. Porter, John F. Trant

Chemistry and Biochemistry Publications

(S)-2,4-Diaminobutanoic acid (DABA) is a noncanonical amino acid often co-produced by cyanobacteria along with β-N-methylamino-l-alanine (BMAA) in algal blooms. Although BMAA is a well-established neurotoxin, the toxicity of DABA remains unclear. As part of our development of biocompatible materials, we wish to make use of DABA as both a building block and as the end-product of enzymatically-induced depolymerization; however, if it is toxic at very low concentrations, this would not be possible. We examined the toxicity of DABA using both in vivo embryonic and adult zebrafish models. At higher sub-lethal concentrations (700 µM), the fish demonstrated early …

Effects Of Halogen, Chalcogen, Pnicogen, And Tetrel Bonds On Ir And Nmr Spectra, Jia Lu, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Complexes were formed pairing FX, FHY, FH₂Z, and FH₃T (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) with NH₃ in order to form an A⋯N noncovalent bond, where A refers to the central atom. Geometries, energetics, atomic charges, and spectroscopic characteristics of these complexes were evaluated via DFT calculations. In all cases, the A–F bond, which is located opposite the base and is responsible for the σ-hole on the A atom, elongates and its stretching frequency undergoes a shift to the red. This …

An Unexpected Rhenium(Iv)–Rhenium(Vii) Salt: [Co(Nh3)6]3[Reviio4][Reivf6]46h2o, James Louis_Jean, Samudee Mariappan Balasekaran, Adelheid Hagenbach, Frederic Poineau

Chemistry and Biochemistry Faculty Research

The title hydrated salt, tris[hexaamminecobalt(III)] tetraoxidorhenate(VII) tetrakis[hexafluoridorhenate(IV)] hexahydrate, arose unexpectedly due to possible contamination of the K2ReF6 starting material with KReO4. It consists of octahedral [Co(NH3)6] 3+ cation (Co1 site symmetry 1), tetrahedral [ReVIIO4] anions (Re site symmetry 1) and octahedral [ReIVF6] 2 anions (Re site symmetries 1and 3). The [ReF6] 2 octahedral anions (mean Re—F = 1.834 A˚ ), [Co(NH3)6] 3+ octahedral cations (mean Co—N = 1.962 A˚ ), and the [ReO4] tetrahedral anion (mean Re—O = 1.719 A˚ ) are slightly distorted. A network of N—HF hydrogen bonds consolidates the structure. The crystal studied was refined as a …