Molecular Magnets of Re(IV)

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Chemistry

Abstract

Magnets are ubiquitous in modern society, employed in an enormous range of applications from biomedical imaging and cancer therapy to information technology, national and international defence and security, and outer-space research. One of the main goals of modern research, in both the industrial and academic sectors, is the miniaturisation of such technologies. This is entirely reliant upon fundamental scientific research, and the investigation and understanding of the intrinsic relationship between structure and magnetic behaviour. This requires chemists to design and build families of molecules and molecule-based materials, and through extensive collaboration with a network of condensed matter physicists, theoreticians and materials scientists, understand and ultimately exploit their underlying physical properties. This was demonstrated beautifully with the recent construction of single-molecule spin valves and transistors by Wernsdorfer and co-workers, and through IBMs report of information storage in surface arrays of Fe atoms. The academic field of molecular magnetism represents an atom-by-atom, molecule-by-molecule approach to building new magnetic materials. The molecular or "bottom-up" approach has many potential advantages over the "top-down" approach: molecules are soluble, monodisperse in size and shape, amenable to change through simple synthetic chemistry generating materials with tuneable, designer, physical properties. This proposal first concerns the synthesis, structural and magnetic characterisation of a library of mononuclear complexes based on highly anisotropic 4/5d ions. These complexes are then used as metalloligands towards 3d metal ions or complexes, promising a rational route toward the construction of pre-designed metal cages with predictable structures and tuneable magnetic behaviour. It also involves the attachment of anisotropic metalloligands to well-known and well characterised, pre-made molecular magnets, such as Co4, Mn6, Ni12, Fe17, in order to examine the effect on magnetisation relaxation dynamics and to derive detailed magneto-structural correlations.

Planned Impact

UK-plc
Magnetic materials are ubiquitous in society, shaping the way we live our daily lives and greatly impacting the academic and industrial sectors. Data storage on PCs, tablets and smart phones, MRI scanners in hospitals and the treatment of cancer via thermotherapy; instrument cooling in security instrumentation such as airport scanners, and astronomical radiation detectors employed in the search for the keys to the origin of the universe, are just a few examples of science based on magnetic materials. These are multi-billion pound per annum industries with clear benefits to the UK economy, and the continual evolution of such technologies ensures that the potential for future exploitation is vast, with technological improvements equating to significant added-value. One key driver is device miniaturisation, and this clearly points toward a bottom-up or molecular approach to the science. This also aligns it to EPSRC Grand Challenges and UK priority areas of funding, since novel molecule-based technologies will have impact upon all of these areas. If novel Intellectual Property arises, our Business Development Executive Stuart Duncan will provide advice on potential avenues for industrial partnership, with existing University partners canvassed to assess interest and identify routes for future collaboration, exploitation and application.
Policymakers and the Public
Although magnets underpin much of modern society, it's unlikely that the public, politicians and policymakers would link university chemistry and physics to magnets and to, for example, the storage of information on their computers or mobile devices, or to hospital MRI scanners. The world-leading academic outputs from this program of research will be disseminated widely to academia, the public, to industry and government, in order to begin to address this missing link. Here, The University of Edinburgh has the unique advantage of being in the same city as the home of the Scottish Government, and the College of Science and Engineering exploits this via regular 'Science in the Parliament' days at Holyrood. This is an opportunity to talk to, and influence, government decision makers, allowing academics to highlight the importance of supporting fundamental scientific research. The diverse public engagement and outreach program targeting UK HEIs, schools and the wider public will ensure our fundamentals-to-application message clarifies the importance of lab-based chemistry and physics on evolving modern information technology. Computers, smart phones and tablets, anti-cancer diagnostics and treatments, and Outer Space Exploration are just some of the simple popularity hooks that can drive public interest.
Education, Training and Mobility
EKB and the School of Chemistry at The University of Edinburgh (UoE) provide a world-class environment for scientific research, training and career development. The PDRA will be trained to think and work in an interdisciplinary manner, and collaboration with an international network of renowned physicists and theoreticians will allow access to a plethora of scientific techniques and methodolgies, equipping the PDRA with experience/expertise in a variety of key skills. Visits to our overseas collaborators (Hill (EPR) and Cano (theory)) will serve to further enhance their contact base that will be invaluable in any technical or intellectually challenging line of work in the future. The Institute for Academic Development at UoE is a recognised centre of excellence for the provision of transferable skills, and the PDRA will benefit from the enormous range of training opportunities available to them. This encompasses research communication and presentation through to publicity and media training, and business methodology and entrepreneurship; initiatives which match the aims of RCUK.

Publications

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Martínez-Lillo J (2014) Metamagnetic behaviour in a new Cu(II)Re(IV) chain based on the hexachlororhenate(IV) anion. in Chemical communications (Cambridge, England)

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Martínez-Lillo J (2015) The effect of crystal packing and Re(IV) ions on the magnetisation relaxation of [Mn6]-based molecular magnets. in Chemistry (Weinheim an der Bergstrasse, Germany)

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Pedersen AH (2017) Hexahalorhenate(iv) salts of metal oxazolidine nitroxides. in Dalton transactions (Cambridge, England : 2003)

 
Description Magnets are ubiquitous in modern society, employed in an enormous range of applications from information storage, biomedical imaging and cancer therapy to space research. One of the main goals of modern academic and industrial research is device miniaturization, and a bottom-up or molecular approach to building components represents an attractive methodology. The synthesis of molecules whose behaviour resembles that of classical bulk magnets has been an important challenge for several decades. Here, the physical behaviour is, in part, governed by the magnetic anisotropy of the molecule, which in turn originates from symmetry and structure, factors that are a challenge to control via synthetic chemistry. An alternative way of harnessing and exploiting magnetic anisotropy, and other important factors such as the nature and strength of intra- and intermolecular exchange interactions, is through the use of pressure, since the latter can be used to modify intramolecular bond lengths, angles and metal geometries, and important intermolecular interactions such as H-bonds, C-H···p and p···p contacts, amongst others. Magnetic anisotropy also plays a significant role in spin-canted systems, which behave as weak ferromagnets. In these systems, magnetic order originates from the non-colinearity of neighbouring spin centres which are 'canted' at a particular angle (a) with respect to each other. Importantly the non-negligible intermolecular magnetic interactions can be modified by changing intermolecular distances, e.g. making these distances shorter would be expected to increase the strength of the exchange and increase the ordering temperature, Tc. An obvious way of achieving this is to exert hydrostatic pressure, and by combining high pressure single crystal X-ray crystallography and high pressure SQUID magnetometry the exact relationship between changing structure and changing magnetic behaviour can be extracted.
Exploitation Route Materials that demonstrate long range magnetic order are synonomous with information storage and the electronics industry, with the phenomenon commonly associated with metals, metal alloys or metal oxides and sulfides. A lesser know family of magnetically ordered complexes are the monometallic compounds of highly anisotropic d-block transition metals; the 'transformation' from isolated 0D molecule to ordered, spin-canted, 3D lattice being the result of through-space [dipolar] interactions arising from the combination of large magnetic anisotropy and spin-delocalization from metal to ligand which induces important intermolecular contacts.
Sectors Chemicals,Digital/Communication/Information Technologies (including Software),Education,Electronics,Energy,Other

URL http://www.chem.ed.ac.uk/staff/academic-staff/professor-euan-k-brechin
 
Description University of Valencia 
Organisation University of Valencia
Country Spain 
Sector Academic/University 
PI Contribution Synthesis, magnetic studies of Re(IV) complexes
Collaborator Contribution Theory
Impact Several high impact academic papers examining the coordination chemistry and magnetic behaviour of Re(IV) species.
Start Year 2014