EMR Science Highlights
Novel metallofullerene boosts dynamic nuclear polarization
In this study, researchers added a low concentration of the endohedral metallofullerene (EMF) Gd2@C79N to DNP samples, finding that 1H and 13C enhancements increased by 40% and 50%, respectively, at 5 teslas and 1.2 Kelvin.
Across the Tree of Life: Radiation Resistance Gauged by High-Field EPR
This high-field EPR study of the H-Mn2+ content in the bacterium Deinococcus Radiodurans provides the strongest known biological indicator of cellular ionizing radiation resistance between and within the three domains of the tree of life, with potential applications including optimization of radiotherapy.
Reversible magnetic switching in multifunctional material
With just a drop of water, a cobalt-based material changes both color and magnetic properties.
![Representative high-field EPR data and structural details of the (PPh4)2[Co(SPh)4] molecule.](/media/k2/items/cache/1706b33fef7712ba31cca5e36abb2536_S.jpg)
Magneto-structural correlations in a transition metal complex
In the field of inorganic chemistry, magneto-structural correlations have been used to rationally design molecules with desirable properties, and to relate these properties to the electronic and geometric structures. In turn, such studies provide powerful tools for understanding important catalytic processes, as well as elucidating the structures of active sites in metalloproteins. This study reveals an unusually strong sensitivity of the magnetic properties of a CoS4 molecule to minute changes in its structure.
Symmetry reduction in a quantum kagomé antiferromagnet
This area of research could help scientists understand high-temperature superconductivity and other mysteries.
Potential qubits maintain quantum coherence outside a crystal
This approach to building “qubits” could be a promising tool for developing quantum computers.
New record magnetic anisotropy in a molecular nanomagnet
Scientists created a molecular nanomagnet based on a single nickel atom with record-high magnetic anisotropy — a quality that makes it a promising building block for applications like memory storage.
Tweaking molecular structure to tune chemical reactivity
A recent high-field EPR study by MagLab users from Wayne State and Grand Valley State Universities has demonstrated that minor changes in the periphery of a nickel-containing molecule can lead to a dramatic reorganization of its electron distribution. This in turn, induces a major shift in the reactivity of this compound.
An approach for dynamic nuclear polarization of membrane proteins
Dynamic nuclear polarization (DNP) coupled with solid state NMR can provide orders of magnitude enhancement to normally weak NMR signals, thereby enabling the study of inherently dilute proteins such as membrane proteins. Here we demonstrate a new approach to obtain DNP signal enhancements of membrane proteins by utilizing spin labeled lipids as the polarization agents. This strategy results in more than 2x in signal enhancements of a membrane protein when compared to standard DNP sample preparation techniques.
Controlled Under Pressure: Exchange Anisotropy in Organic Magnets
MagLab users have employed a combination of ab-initio theory and a newly developed high-pressure, high-field ferromagnetic resonance technique, which is uniquely sensitive to anisotropic magnetic interactions, to gain insights into the importance of spin-orbit coupling effects in a range of organic materials where this effect is usually considered to be small. The findings may be applicable to topics as diverse as spintronics and topological spin phases.
Detailed Spectroscopic Study of a Square Planar High-Spin FeII Complex
Square-planar high-spin Fe(II) molecular compounds are rare. Using an easily modifiable pincer-type ligand, the successful synthesis of the first compound of this type that breaks the FeO4 motif was achieved, and the first spectroscopic evidence that the geometry and spin state persist in solution was obtained.
Influence of Electronic Spin and Spin−Orbit Coupling on Decoherence in Transition Metal Complexes
Enabling the rational synthesis of molecular candidates for quantum information processing requires design principles that minimize electron spin decoherence. Two series of paramagnetic coordination complexes, [M(C2O4)3]3- (M = Ru, Cr, Fe) and [M(CN)6]3- (M = Fe, Ru, Os), were prepared and subsequently interrogated by pulsed electron paramagnetic resonance spectroscopy to assess quantitatively the influence of the magnitude of spin (S = 1/2, 3/2, 5/2) and spin–orbit coupling (ζ = 464, 880, 3100 cm–1) on decoherence. The results illustrate that the design of qubit candidates can be achieved with a wide range of paramagnetic ions and spin states while preserving a long-lived coherence.
High-Field EPR Studies of the Mn(II) Centers in Bacillus subtilis Oxalate Decarboxylase
Oxalate Decarboxylase (OxDC) is an enzyme that catalyzes the manganese-dependent breakdown of the oxalate monoanion into carbon dioxide and formate. EPR measurements performed at very high magnetic fields greatly simplify the task of assigning fine structure parameters to each of the Mn(II) centers in wild-type OxDC. The results provide new insights into the strengths and limitations of theoretical methods for understanding protein-bound Mn(II), setting the stage for future EPR studies of Mn(II) centers in OxDC.
All-Electrical Nuclear Spin Polarization of Donors in Silicon
Measurements performed in the EMR program demonstrate that the nuclear spins associated with donor states in silicon field-effect transistors can be polarized at high magnetic fields by controlling the current and gate voltage on the device, i.e., the nuclear polarization can be controlled purely by electrical means.
Giant Ising-Type Magnetic Anisotropy in Trigonal Bipyramidal Ni(II) Complexes
Research suggests that anisotropy in the high-symmetry coordination environment of Ni(II) complex is an order of magnitude larger than any previously known.
High-Frequency and -Field EPR Detection of a Di-radical Intermediate
This work defines a new mechanism for radical-mediated catalysis of a protein substrate, and has broad implications for applied biocatalysis and for understanding oxidative protein modification during oxidative stress.
Di-Nitrogen Activation by Vanadium(III) Complexes for Chemical Catalysis
Researchers from the National High Magnetic Field Laboratory user program performed high-frequency (329 GHz) electron magnetic resonance (EMR) experiments to address questions of fundamental importance in catalysis 1) improving industrial production of ammonia and ammonia-derived fertilizers, and 2) understanding of the atmospheric nitrogen cycle.