Magnetic Coordination Capsules: Establishing a Rationally-Designed, Paramagnetic Host-Guest Approach to Molecular Magnets.

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

Abstract

Coordination capsules are a subset of what are often referred to as molecular container species i.e. compounds with hollow internal voids that are capable of encapsulating one or more whole other molecule. In contrast to fully organic molecular container species (i.e. those that are composed of only carbon, nitrogen, hydrogen and oxygen), coordination capsules are held together using metal-ligand bonds. This provides several advantages over the former, firstly, as metal ligand bonds are often dynamic they can be prepared using self-assembly reactions. This is the process whereby multiple individual components react to form a single species, wherein "mistakes" can be corrected because of the dynamics of the metal-ligand bonds, such that the system is able to "select" the most stable entity. The second attractive facet of coordination systems is that the metallic elements themselves can be used to imbue the capsule with various interesting properties often not associated with fully organic congeners.

In this proposal, we are interested in employing metallic elements that contain unpaired electrons. In a capsule that contains multiple metal centres with unpaired electrons, these can "communicate" through the ligand framework, such that the unpaired electrons of at one metal site can influence the orientation of spin (either up or down) of an electron at an adjacent site. In this proposal, we want to go a step further than has previously been accomplished. We want to demonstrate that it is possible to take the magnetic capsule and encapsulate a species that contains further unpaired electrons. This in turn will affect the magnetic properties of the capsule system, even though there is no direct chemical (covalent) bond between the encapsulated species and the capsule. Overall, this project will aim to further develop our understanding of magneto-structural relationships.

From a real-world perspective, there are various applications of magnetic materials, ranging from refrigeration, information storage devices and quantum information processing, through to medical applications such as imaging and thermotherapy.

Planned Impact

A combination of providing individuals with the necessary skills to advance their careers, cementing an evolving collaboration, raising the UKs international research standing in multiple areas via the high-profile dissemination of results through primary-literature outlets, engaging with the general public, inspiring the next generation of UK scientists, allowing commercial opportunities to be fully realised are all prime impact targets. The science we propose here - a cross-fertilisation of ideas from the fields of supramolecular capsules and molecular magnetism - would push each individual area into new directions. Furthermore, the technology developed in this proposal could have far-reaching applications in areas such as information technology and molecular spintronics.

In regards of training, the PI &CoI have a tremendous track record in the training and mentoring of PDRAs and PhD students, many of whom have gone on to forge their own independent academic careers. Examples include:
1. Dr Constantinos J. Milios, School of Chemistry, The University of Crete, Greece.
2. Dr Alessandro Prescimone, School of Chemistry, The University of Basle, Switzerland.
3. Dr Ian Gass, School of Chemistry, The University of Brighton, UK.
4. Dr Leigh Jones, School of Chemistry, Bangor University, UK.
5. Dr Georgios Karotsis, School of Chemistry, Environmental and Life Sciences, College of the Bahamas.
6. Dr Ross Inglis, School of Chemistry, The University of Edinburgh, UK.
7. Dr Maria Palacios, School of Chemistry, The University of Granada, Spain.
8. Dr Jose Martinez-Lillo, School of Chemistry, The University of Valencia, Spain.
Prescimone was awarded the European Prize for a Doctoral Thesis on Molecular Magnetism (2010); Inglis the Dalton Young Researchers Award (2012) and Royal Society of Edinburgh Fellowship (2013). Brechin was also recently elected "Postdoc Champion" in the EaStCHEM School of Chemistry, The University of Edinburgh (2016-present) to promote the scientific achievements of postdoctoral researchers, nurture talent, ensure their welfare, and provide bespoke career advice.

Publications

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Dearle AE (2019) An [FeIII 34 ] Molecular Metal Oxide. in Angewandte Chemie (International ed. in English)

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Dearle AE (2021) An [FeIII30] molecular metal oxide. in Chemical communications (Cambridge, England)

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Fraser HWL (2018) Cages on a plane: a structural matrix for molecular 'sheets'. in Dalton transactions (Cambridge, England : 2003)

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Fraser HWL (2021) [(VIVO)2MII5] (M = Ni, Co) Anderson wheels. in Dalton transactions (Cambridge, England : 2003)

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Fraser HWL (2018) Order in disorder: solution and solid-state studies of [MM] wheels (MIII = Cr, Al; MII = Ni, Zn). in Dalton transactions (Cambridge, England : 2003)

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Fraser HWL (2018) A simple methodology for constructing ferromagnetically coupled Cr(iii) compounds. in Dalton transactions (Cambridge, England : 2003)

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Ignaszak A (2018) Vanadyl sulfates: molecular structure, magnetism and electrochemical activity. in Dalton transactions (Cambridge, England : 2003)

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Kakaroni FE (2019) A Ferromagnetically Coupled, Bell-Shaped [Ni4Gd5] Cage. in Inorganic chemistry

 
Description This investigation is currently ongoing. We have currently established a procedure to make paramagnetic host-guest complexes in accordance with the outlined proposal. Moreover, we have recently discovered that it is possible to change SMM behaviour using encapsulation of diamagnetic guests into a paramagnetic cage complex. While the origin of this change is being investigated, we are currently working on the theory changes the coordination and structure geometry, which in turn affects the magnetic properties.
Exploitation Route Prime impact targets were identified as providing individuals with the necessary skills to advance their careers, cementing an evolving collaboration, raising the UKs international research standing in multiple areas via the high-profile dissemination of results through primary-literature outlets, inspiring the next generation of UK scientists, allowing commercial opportunities to be fully realized. In the context of a year into this grant, we have achieved what could be expected at this stage.
Sectors Aerospace, Defence and Marine,Chemicals,Digital/Communication/Information Technologies (including Software),Electronics