Category Archives: paramagnetic materials

Enabling Natural Abundance 17O Solid-State NMR by Direct Polarization from Paramagnetic Metal Ions #DNPNMR

Jardón-Álvarez, Daniel, Guy Reuveni, Adi Harchol, and Michal Leskes. “Enabling Natural Abundance 17O Solid-State NMR by Direct Polarization from Paramagnetic Metal Ions.” The Journal of Physical Chemistry Letters 11, no. 14 (July 16, 2020): 5439–45.

https://doi.org/10.1021/acs.jpclett.0c01527.

Dynamic nuclear polarization (DNP) significantly enhances the sensitivity of nuclear magnetic resonance (NMR), increasing applications and quality of NMR as a characterization tool for materials. Efficient spin diffusion among the nuclear spins is considered to be essential for spreading the hyperpolarization throughout the sample enabling large DNP enhancements. This scenario mostly limits the polarization enhancement of low sensitivity nuclei in inorganic materials to the surface sites when the polarization source is an exogenous radical. In metal ions based DNP, the polarization agents are distributed in the bulk sample and act as both source of relaxation and of polarization enhancement. We have found that as long as the polarization agent is the main source of relaxation, the enhancement does not depend on the distance between the nucleus and dopant. As a consequence, the requirement of efficient spin diffusion is lifted and the entire sample can be directly polarized. We exploit this finding to measure high quality NMR spectra of 17O in the electrode material Li4Ti5O12 doped with Fe(III) despite its low abundance and long relaxation time.

[NMR] Training Courses on Paramagnetic NMR and Metal Trafficking

Dear Colleagues,

Please forward this announcement to all your colleagues and to any potential candidate, thank you.

TRAINING COURSE : FUNDAMENTALS OF MAGNETIC RESONANCE SPECTROSCOPIES AND

METAL TRAFFICKING

HANDS-ON WORKSHOP: NMR OF PARAMAGNETIC PROTEINS AND APPLICATIONS

Two Training Events, dedicated to PhD Students and PostDoc working in the field of Biomolecular NMR and/or in Metalloprotein Chemistry, will be organized in the period June 22nd-June 26th at the Magnetic Resonance Center of the University of Florence.

A three days Training Course on Fundamentals of Magnetic Resonance Spectoscopies and Metal Trafficking will be followed by a two Hands-on Workshop on NMR of Paramagnetic Proteins and Applications. Both initiatives are supported by the TIMB3 Project, a Twinning project funded by the European Union. Deadline for application is February 29th.

Please follow the link for the detailed program:

http://www.cerm.unifi.it/images/stories/Documents/School_CERM-final4.pdf

http://www.cerm.unifi.it/images/stories/Documents/Workshop_CERM-final4.pdf

For further information write to: nmrtraining2020@cerm.unifi.it

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Perspectives on paramagnetic NMR from a life sciences infrastructure

Ravera, E., G. Parigi, and C. Luchinat, Perspectives on paramagnetic NMR from a life sciences infrastructure. J Magn Reson, 2017. 282(Supplement C): p. 154-169.

https://www.ncbi.nlm.nih.gov/pubmed/28844254

The effects arising in NMR spectroscopy because of the presence of unpaired electrons, collectively referred to as “paramagnetic NMR” have attracted increasing attention over the last decades. From the standpoint of the structural and mechanistic biology, paramagnetic NMR provides long range restraints that can be used to assess the accuracy of crystal structures in solution and to improve them by simultaneous refinements through NMR and X-ray data. These restraints also provide information on structure rearrangements and conformational variability in biomolecular systems. Theoretical improvements in quantum chemistry calculations can nowadays allow for accurate calculations of the paramagnetic data from a molecular structural model, thus providing a tool to refine the metal coordination environment by matching the paramagnetic effects observed far away from the metal. Furthermore, the availability of an improved technology (higher fields and faster magic angle spinning) has promoted paramagnetic NMR applications in the fast-growing area of biomolecular solid-state NMR. Major improvements in dynamic nuclear polarization have been recently achieved, especially through the exploitation of the Overhauser effect occurring through the contact-driven relaxation mechanism: the very large enhancement of the (13)C signal observed in a variety of liquid organic compounds at high fields is expected to open up new perspectives for applications of solution NMR.

[NMR] PhD position in solid-state NMR of paramagnetic materials

A PhD position is available in the group of Andrew Pell at the Department of Materials Environmental and Environmental Chemistry (MMK), Stockholm University (Sweden), in solid-state NMR of paramagnetic materials.

Closing date: August 7, 2017.

Project description

The aim of our research is to develop solid-state nuclear magnetic resonance (NMR) methods in order to allow a more accurate characterization, at the atomic scale, of the structure and dynamics of increasingly complex materials that are relevant in modern material science and chemistry. Specifically we focus on systems that contain paramagnetic metal ions, and how these ions dictate the properties of technologically important materials such as batteries, catalysts, and solid-state lighting phosphors.

Solid-state NMR is the method of choice for studying local structure and dynamics. However many interesting paramagnetic materials are, for technical reasons, beyond the ability of the current state of the art in solid-state NMR to study. This PhD project is therefore focussed on developing and specifically tailoring the techniques and capabilities of solid-state NMR for the analysis of samples containing these metal ions; for characterizing their presence, activity, role, and function in a range of different materials. Specifically the PhD student will develop new pulse schemes for exciting and detecting the NMR signals from quadrupolar nuclei (such as 2H, 14N, 23Na, 25Al, …) in paramagnetic materials, and incorporate these new schemes into more sophisticated experiments in order to separate the information from different spin interactions, which can then be interpreted in terms of both the structure and dynamics of the system. These new methods will then be applied to a range of paramagnetic materials, such as battery electrodes, ion conductors, or inorganic phosphors, with the specific choice depending on the interests of the student.

The student will acquire expertise in both the theoretical and experimental aspects of solid-state NMR on 400 and 600 MHz Bruker spectrometers. There will also be opportunities to travel to high-field NMR centres both within Sweden and Europe. Following the development of the new NMR methods the student will have the opportunity to apply them on a range of different materials that have been developed both at MMK and in collaboration with other laboratories around the world.

The project is interdisciplinary and contains elements from chemistry and physics. Therefore, strongly motivated students with a background in these areas, and particularly those with an interest in quantum mechanics, are encouraged to apply.

The Department of Materials and Environmental Chemistry, Stockholm University

The Department of Materials- and Environmental Chemistry (MMK) is one of the largest departments at the Faculty of Natural sciences with about 140 employees. The research activities of MMK are in the areas of Materials and Solid-state Chemistry focusing on different classes of materials; e.g. ceramics and glasses, self-assembled and porous materials, and soft matter. The work often encompasses synthesis, characterisation by X-ray diffraction and electron microscopy, NMR studies, modelling with computer simulations of materials with a potential for various applications. Environmental aspects are an important part of the research activities.

Application

For informal enquiries, email Andrew Pell at andrew.pell@mmk.su.se.

To obtain more information about the position, how to apply, and to submit your application visit http://www.su.se/english/about/vacancies/vacancies-new-list?rmpage=job&rmjob=3062&rmlang=UK

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Andrew J. Pell

Assistant Professor

Department of Materials and Environmental Chemistry,

Arrhenius Laboratory,

Stockholm University,

Svante Arrhenius väg 16C,

SE-106 91 Stockholm,

Sweden

Webpage: http://www.su.se/profiles/apell-1.255858

Tel: +46 (0)8-16 23 76

Email: andrew.pell@mmk.su.se

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