NMR and EPR

Molecular systems important to biology, environmental remediation and sustainability are studied using a suite of nuclear magnetic resonance (NMR) spectrometers with frequencies ranging from 300 to 850 MHz. A pair of electron paramagnetic resonance (EPR) spectrometers complement the capability.

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Description

Interfacial and in situ biology—Innovative NMR instrumentation and techniques for probing properties of macromolecular cellular assemblies and in situ and ex situ metabolic processes, as well as for exploring biological membrane proteins in the solid state. Unique EPR and variable-temperature NMR approaches to explore structure and properties of redox metal centers critical catalysis, environmental chemistry and cell biology.

Environmental chemistry— EMSL offers a unique NMR system for radiological studies. Users can perform magic angle spinning of highly radioactive samples with a novel hermetically sealed 3.2mm NMR probe. These tools allow users to apply NMR techniques to critical areas of radiological research, including the study of radioactive waste processing and storage.

Interfacial and in situ chemistry—Leading-edge solid-state NMR probe technology to analyze and quantify properties of advanced energy materials, fuel cells and real-time catalytic processes. High power pulsed field gradient diffusion capabilities for liquid and solid samples.

 EMSL offers unique and custom NMR and EPR tools, including probes for specialized studies.

  • NMR spectrometers, ranging from 300 MHz to 850 MHz for high-field liquid-state, solid-state and micro-imaging techniques
  • W- and X-band pulsed EPR spectremeter for probing metal centers in biological and materials systems
  • NMR metabolomics capabilities
  • Extreme-temperature probes, both high and low temperatures
  • Virtual NMR tools for remote access to spectrometer systems.

Instruments

Research applications Samples containing paramagnetics Soils (SOM and NOM) Metal oxide materials for catalysis applications Researchers may operate...
Custodian(s): Nancy Washton, Sarah D Burton
Highlighted Research Applications Characterization of natural and soil organic matter (NOM and SOM) CO2 sequestration investigations via high-...
Custodian(s): Sarah D Burton
Highlighted Research Applications EMSL's Bruker 500-MHz WB spectrometer is uniquely tailored for in vivo studies: Microbial biofilms relevant to...
Custodian(s): Ryan Renslow
Type of Instrument:
Nuclear Magnetic Resonance Spectrometer (NMR)
Highlighted Research Applications Dynamics studies via 2H NMR Characterization of quadrupolar nuclei for materials and biological samples In situ...
Highlighted Research Applications Structural biology Protein structure and dynamics Nuclei acid structure and dynamics. Metabolomics Eukaryotic and...
Custodian(s): Nancy Isern

Publications

The oxygen reduction/evolution reaction (ORR/OER) mechanisms in nonaqueous Li-O2 batteries have been investigated by using electron paramagnetic...
The syntheses of the new 1,5-diphenyl-3,7-di(isopropyl)-1,5-diaza-3,7-diphosphacyclooctane ligand, PiPr2NPh2, is reported. The two equivalents of the...
The purpose of this study was to determine the solubility of iodine in a low-activity waste borosilicate glass when heated inside an evacuated and...
In H2 fuel cells, performance depends on factors controlling turnover frequency and energy efficiency in the electrocatalytic oxidation of H2. Nature...
Understanding hydrogen formation on TiO2 surfaces is of great importance as it could provide fundamental insight into water splitting for hydrogen...

Science Highlights

Posted: November 21, 2014
The Science Carbon dioxide (CO2) sequestration in deep subsurface environments has received significant attention and investment as a way to reduce...
Posted: August 14, 2014
Industry uses zeolites as an ion exchange material and solid acid to catalyze a broad range of chemical reactions. Zeolites are also promising...
Posted: June 23, 2014
Congratulations to Pacific Northwest National Laboratory and EMSL researchers on being named highly cited authors for 2012-2013 by the Journal of...
Posted: November 12, 2013
Tiny electrical wires protrude from some bacteria and contribute to rock and dirt formation. Researchers studying the protein that makes up one such...
Posted: May 22, 2013
Bacteria can move electrons at least half a millimeter across a scaffolding made by themselves, of themselves, even under starving conditions. This...

Molecular systems important to biology, environmental remediation and sustainability are studied using a suite of nuclear magnetic resonance (NMR) spectrometers with frequencies ranging from 300 to 850 MHz. A pair of electron paramagnetic resonance (EPR) spectrometers complement the capability.

Additonal Information:

Attachments: 

A Ni(II) Bis(diphosphine)-Hydride Complex Containing Proton Relays - Structural Characterization and Electrocatalytic Studies.

Abstract: 

The syntheses of the new 1,5-diphenyl-3,7-di(isopropyl)-1,5-diaza-3,7-diphosphacyclooctane ligand, PiPr2NPh2, is reported. The two equivalents of the ligand react with [Ni(CH3CN)6](BF4)2 to form the bis-diphosphine Ni(II)-complex [Ni(PiPr2NPh2)2](BF4)2, which acts as a proton reduction electrocatalyst. In addition to [Ni(PiPr2NPh2)2]2+, we report the syntheses and structural characterization of the Ni(0)-complex Ni(PiPr2NPh2)2, and the Ni(II)-hydride complex [HNi(PiPr2NPh2)2]BF4. The [HNi(PiPr2NPh2)2]BF4 complex represents the first Ni(II)-hydride in the [Ni(PR2NR'2)2]2+ family of compounds to be isolated and structurally characterized. In addition to the experimental data, the mechanism of electrocatalysis facilitated by [Ni(PiPr2NPh2)2]2+ is analyzed using linear free energy relationships recently established for the [Ni(PR2NR'2)2]2+ family. We thank Dr. Aaron Appel, Dr. Simone Raugei and Dr. Eric Wiedner for helpful discussions. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Mass spectrometry was provided at W. R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy’s office of Biological and Environmental Research located at Pacific Northwest National Laboratory. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.

Citation: 
Das PP, RM Stolley, EF Van Der Eide, and ML Helm.2014."A Ni(II) Bis(diphosphine)-Hydride Complex Containing Proton Relays - Structural Characterization and Electrocatalytic Studies."European Journal of Inorganic Chemistry 27:4611-4618. doi:10.1002/ejic.201402250
Authors: 
PP Das
RM Stolley
EF Van Der Eide
ML Helm
Facility: 
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Publication year: 
2014

The Mechanisms of Oxygen Reduction and Evolution Reactions in Nonaqueous Lithium-Oxygen Batteries.

Abstract: 

The oxygen reduction/evolution reaction (ORR/OER) mechanisms in nonaqueous Li-O2 batteries have been investigated by using electron paramagnetic resonance spectroscopy in this work. We identified the superoxide radical anion (O2•-) as an intermediate in the ORR process using 5,5-dimethyl-pyrroline N-oxide as a spin trap, while no O2•- in OER was detected during the charge process. These findings provide insightful understanding on the fundamental oxygen reaction mechanisms in rechargeable nonaqueous Li-O2 batteries.

Citation: 
Cao R, ED Walter, W Xu, EN Nasybulin, P Bhattacharya, ME Bowden, MH Engelhard, and J Zhang.2014."The Mechanisms of Oxygen Reduction and Evolution Reactions in Nonaqueous Lithium-Oxygen Batteries."ChemSusChem 7(9):2436-2440. doi:10.1002/cssc.201402315
Authors: 
R Cao
ED Walter
W Xu
EN Nasybulin
P Bhattacharya
ME Bowden
MH Engelhard
J Zhang
Instruments: 
Volume: 
7
Issue: 
9
Pages: 
2436-2440
Publication year: 
2014

Iodine Solubility in Low-Activity Waste Borosilicate Glass at 1000 °C.

Abstract: 

The purpose of this study was to determine the solubility of iodine in a low-activity waste borosilicate glass when heated inside an evacuated and sealed fused quartz ampoule. The iodine was added to glass frit as KI in quantities of 100–24000 ppm iodine (by mass), each mixture was added to an ampoule, the ampoule was heated at 1000 °C for 2 h and then air quenched. In samples with ≥12000 ppm iodine, low viscosity salt phases were observed on the surface of the melts during cooling that solidified into a white coating upon cooling. These salts were identified as mixtures of KI, NaI, and Na2SO4 with X-ray diffraction (XRD). The iodine concentrations in glass specimens were analyzed with inductively-coupled plasma mass spectrometry and the overall iodine solubility was determined to be 10000 ppm by mass. Several crystalline inclusions of iodine sodalite, Na8(AlSiO4)6I2, were observed in the 24000 ppm specimen and were verified with micro-XRD and wavelength dispersive spectroscopy.

Citation: 
Riley BJ, MJ Schweiger, DS Kim, WW Lukens, BD Williams, C Iovin, CP Rodriguez, NR Overman, ME Bowden, DR Dixon, JV Crum, JS Mccloy, and AA Kruger.2014."Iodine Solubility in Low-Activity Waste Borosilicate Glass at 1000 °C."Journal of Nuclear Materials 452(1-3):178-188. doi:10.1016/j.jnucmat.2014.04.027
Authors: 
BJ Riley
MJ Schweiger
DS Kim
WW Lukens
BD Williams
C Iovin
CP Rodriguez
NR Overman
ME Bowden
DR Dixon
JV Crum
JS Mccloy
AA Kruger
Volume: 
452
Issue: 
Pages: 
178-188
Publication year: 
2014

Structures and Stabilities of (MgO)n Nanoclusters.

Abstract: 

Global minima for (MgO)n structures were optimized using a tree growth−hybrid genetic algorithm in conjunction with MNDO/MNDO/d semiempirical molecular orbital calculations followed by density functional theory geometry optimizations with the B3LYP functional. New lowest energy isomers were found for a number of (MgO)n clusters. The most stable isomers for (MgO)n (n > 3) are 3-dimensional. For n < 20, hexagonal tubular (MgO)n structures are more favored in energy than the cubic structures. The cubic structures and their variations dominate after n = 20. For the cubic isomers, increasing the size of the cluster in any dimension improves the stability. The effectiveness of increasing the size of the cluster in a specific dimension to improve stability diminishes as the size in that dimension increases. For cubic structures of the same size, the most compact cubic structure is expected to be the more stable cubic structure. The average Mg−O bond distance and coordination number both increase as n increases. The calculated average Mg−O bond distance is 2.055 Å at n = 40, slightly smaller than the bulk value of 2.104 Å. The average coordination number is predicted to be 4.6 for the lowest energy (MgO)40 as compared to the bulk value of 6. As n increases, the normalized clustering energy ΔE(n) for the (MgO)n increases and the slope of the ΔE(n)vs n curve decreases. The value of ΔE(40) is predicted to be 150 kcal/mol, as compared to the bulk value ΔE(∞) = 176 kcal/mol. The electronic properties of the clusters are presented and the reactive sites are predicted to be at the corners.

Citation: 
Chen M, AR Felmy, and DA Dixon.2014."Structures and Stabilities of (MgO)n Nanoclusters."Journal of Physical Chemistry A 118(17):3136-3146. doi:10.1021/jp412820z
Authors: 
M Chen
AR Felmy
DA Dixon
Instruments: 
Volume: 
118
Issue: 
17
Pages: 
3136-3146
Publication year: 
2014

Automated High-Pressure Titration System with In Situ Infrared Spectroscopic Detection.

Abstract: 

A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell’s infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct radiation from a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system is demonstrated with three case studies. First, we titrated water into supercritical CO2 (scCO2) to generate an infrared calibration curve and determine the solubility of water in CO2 at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO2 at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay’s sorbed water concentration as a function of scCO2 hydration, and ATR measurements provided insights into competitive residency of water and CO2 on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg2SiO4) in water-bearing scCO2 at 50 °C and 90 bar. Immediately after water dissolved in the scCO2, a thin film of adsorbed water formed on the mineral surface, and the film thickness increased with time as the forsterite began to dissolve. However, after approximately 2.5 hours, the trend reversed, and a carbonate precipitate began to form on the forsterite surface, exposing dramatic chemical changes in the thin-water film. Collectively, these applications illustrate how the high-pressure IR titration system can provide molecular-level information about the interactions between variably wet scCO2 and minerals relevant to underground storage of CO2 (geologic carbon sequestration). The apparatus could also be utilized to study high-pressure interfacial chemistry in other areas such as catalysis, polymerization, food processing, and oil and gas recovery.

Citation: 
Thompson CJ, PF Martin, J Chen, P Benezeth, HT Schaef, KM Rosso, AR Felmy, and JS Loring.2014."Automated High-Pressure Titration System with In Situ Infrared Spectroscopic Detection."Review of Scientific Instruments 85(4):Article No. 044102. doi:10.1063/1.4870411
Authors: 
CJ Thompson
PF Martin
J Chen
P Benezeth
HT Schaef
KM Rosso
AR Felmy
JS Loring
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Publication year: 
2014

Molecular Hydrogen Formation from Proximal Glycol Pairs on TiO2(110).

Abstract: 

Understanding hydrogen formation on TiO2 surfaces is of great importance as it could provide fundamental insight into water splitting for hydrogen production using solar energy. In this work, hydrogen formation from glycols having different numbers of methyl end-groups have been studied using temperature pro-grammed desorption on reduced, hydroxylated, and oxidized TiO2(110) surfaces. The results from OD-labeled glycols demon-strate that gas-phase molecular hydrogen originates exclusively from glycol hydroxyl groups. The yield is controlled by a combi-nation of glycol coverage, steric hindrance, TiO2(110) order and the amount of subsurface charge. Combined, these results show that proximal pairs of hydroxyl aligned glycol molecules and subsurface charge are required to maximize the yield of this redox reaction. These findings highlight the importance of geometric and electronic effects in hydrogen formation from adsorbates on TiO2(110).

Citation: 
Chen L, Z Li, RS Smith, BD Kay, and Z Dohnalek.2014."Molecular Hydrogen Formation from Proximal Glycol Pairs on TiO2(110)."Journal of the American Chemical Society 136(15):5559-5562. doi:10.1021/ja500992b
Authors: 
L Chen
Z Li
RS Smith
BD Kay
Z Dohnalek
Facility: 
Volume: 
136
Issue: 
15
Pages: 
5559-5562
Publication year: 
2014

Arginine-Containing Ligands Enhance H-2 Oxidation Catalyst Performance.

Abstract: 

In H2 fuel cells, performance depends on factors controlling turnover frequency and energy efficiency in the electrocatalytic oxidation of H2. Nature uses the hydrogenase enzymes to oxidize H2 at high turnover frequencies (up to 20,000 s-1) and low overpotentials (<100 mV), while the fastest synthetic catalyst reported to date only oxidizes H2 at 50 s-1 under 1 atm H2. Here we report a water-soluble complex incorporating the amino acid arginine, [NiII(PCy2NArg2)2]6+, that operates at 210 s-1 (180 mV overpotential) under 1 atm H2 and 144,000 s-1 (460 mV overpotential) under 133 atm H2. The complex functions from pH 0-14 with rates increasing at lower pH values. The arginine groups impart water solubility and play a critical role in enhancing turnover frequency, most consistent with an intramolecular Arg-Arg interaction that controls the structure of the catalyst active site. This work was funded by the Office of Science Early Career Research Program through the US DOE, BES (AD, WJS), and the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US DOE, BES (JASR). PNNL is operated by Battelle for the US DOE.

Citation: 
Dutta A, JA Roberts, and WJ Shaw.2014."Arginine-Containing Ligands Enhance H-2 Oxidation Catalyst Performance."Angewandte Chemie International Edition 53(25):6487-6491. doi:10.1002/anie.201402304
Authors: 
A Dutta
JA Roberts
WJ Shaw
Facility: 
Volume: 
53
Issue: 
25
Pages: 
6487-6491
Publication year: 
2014

Ab Initio Thermodynamic Model for Magnesium Carbonates and Hydrates.

Abstract: 

An ab initio thermodynamic framework for predicting properties of hydrated magnesium carbonate minerals has been developed using density-functional theory linked to macroscopic thermodynamics through the experimental chemical potentials for MgO, water, and CO2. Including semiempirical dispersion via the Grimme method and small corrections to the generalized gradient approximation of Perdew, Burke, and Ernzerhof for the heat of formation yields a model with quantitative agreement for the benchmark minerals brucite, magnesite, nesquehonite, and hydromagnesite. The model shows how small differences in experimental conditions determine whether nesquehonite, hydromagnesite, or magnesite is the result of laboratory synthesis from carbonation of brucite, and what transformations are expected to occur on geological time scales. Because of the reliance on parameter-free first principles methods, the model is reliably extensible to experimental conditions not readily accessible to experiment and to any mineral composition for which the structure is known or can be hypothesized, including structures containing defects, substitutions, or transitional structures during solid state transformations induced by temperature changes or processes such as water, CO2, or O2 diffusion. Demonstrated applications of the ab initio thermodynamic framework include an independent means to evaluate differences in thermodynamic data for lansfordite, predicting the properties of Mg analogs of Ca-based hydrated carbonates monohydrocalcite and ikaite which have not been observed in nature, and an estimation of the thermodynamics of barringtonite from the stoichiometry and a single experimental observation.

Citation: 
Chaka AM, and AR Felmy.2014."Ab Initio Thermodynamic Model for Magnesium Carbonates and Hydrates."Journal of Physical Chemistry A 118(35):7469-7488. doi:10.1021/jp500271n
Authors: 
AM Chaka
AR Felmy
Instruments: 
Volume: 
118
Issue: 
35
Pages: 
7469-7488
Publication year: 
2014

C-MYC REGULATES SUBSTRATE OXIDATION PATTERNS DURING EARLY PRESSURE-OVERLOAD HYPERTROPHY.

Abstract: 

Pressure overload cardiac hypertrophy alters substrate metabolism. Prior work showed that myocardial inactivation of c-Myc (Myc) attenuated hypertrophy and decreased expression of glycolytic genes after aortic constriction. Accordingly, we hypothesize that Myc regulates substrate preferences for the citric acid cycle during pressure overload hypertrophy from transverse aortic constriction (TAC) and that these metabolic changes impact cardiac function and growth. To test this hypothesis, we subjected FVB mice with cardiac specific, inducible Myc inactivation (MycKO-TAC) and non-transgenic littermates (Cont-TAC) to transverse aortic constriction (n=7/group). A separate group underwent sham surgery (Sham, n=5). After two weeks, function was measured in isolated working hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketones and unlabeled glucose and insulin. Western blots were used to evaluate metabolic enzymes. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. Compared to Sham, Cont-TAC had increased free fatty acid fractional contribution with a concurrent decrease in unlabeled (presumably glucose) contribution. Myc inactivation (MycKO-TAC) inhibited these metabolic changes. Hypertrophy in general increased protein levels of PKM2; however this change was not linked to Myc status. Protein post-translation modification by O-GlcNAc was significantly greater in Cont-TAC versus both Sham and MycKO-TAC. In conclusion, Myc regulates substrate utilization during early pressure overload hypertrophy. Our results show that the metabolic switch during hypertrophy is not necessary to maintain cardiac function, but it may be important mechanism to promote cardiomyocyte growth. Myc also regulates protein O-GlcNAcylation during hypertrophy.

Citation: 
Ledee DR, L Smith, M Kajimoto, M Bruce, NG Isern, C Xu, MA Portman, and A Olson.2013."C-MYC REGULATES SUBSTRATE OXIDATION PATTERNS DURING EARLY PRESSURE-OVERLOAD HYPERTROPHY."Circulation 128(22 Suppl):Article No. A17989.
Authors: 
DR Ledee
L Smith
M Kajimoto
M Bruce
NG Isern
C Xu
MA Portman
A Olson
Capabilities: 
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Volume: 
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Publication year: 
2013

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