Spin-Crossover Compounds: Switchable Materials from Simple Metal Complexes

Spin-crossover is a high-spin-to-low-spin transition at a transition metal centre, in response to a change in temperature or pressure. This is common in some types of transition metal compound, and especially in iron chemistry. While the molecules in a material undergo spin-crossover individually, it leads to large changes in their size and shape which are propagated through the material in the solid state. <br /> <br /> As one molecule undergoes the transition and changes its size, it causes a change in pressure in the crystal lattice that in turn promotes the transition in its nearest neighbours. These effects are transmitted through a crystal lattice at differing rates, depending on the strength of the interactions between molecules. Hence, whether a particular material undergoes spin-crossover abruptly or gradually, with temperature or with time, is controlled by its crystal packing. As such, spin-crossover materials are good test-beds for theories about crystal engineering.<br /> <br /> Spin-crossover transtions also affect several physical properties of a solid material including its colour, magnetic moment, dielectric constant, hardness and size. These properties have been harnessed in materials applications such as thermochromic inks; stimuli-responsive polymers; switchable microwave absorbers; and solid state refrigeration. Moreover, nanostructures of spin-crossover materials retain their switching properties down to 30 nm length scales, and spin-crossover in single molecules has been detected inside a scanning tunneliing microscope (STM). Spin-crossover nanomaterials science is becoming increasingly sophisticated, and SCO nanoparticle constructs have performed well in prototype binary memory devices.<br /> <br /> Some spin-crossover materials also exhibit thermal hysteresis in their transitions; these are most suitable for the applications mentioned above. Whether a compound undergoes spin-crossover gradually or abruptly, with or without hysteresis, is controlled by the crystal packing in the bulk material rather than the molecule itself. We aim to understand the relationship between structure and function, so we can design new spin-crossover materials from scratch. We are also pursuing different ways to incorporate new functionality into spin-crossover materials.<br /> <br /> We have projects in various aspects of this chemistry, involving organic and inorganic synthesis; crystallography and powder diffraction; solid and solution-phase magnetic measurements; and other techniques as appropriate. Current goals include understanding the principles for designing spin-crossover crystals with bespoke switching properties; new liquid crystals and other soft materials showing spin-crossover switching properties; and, understanding and developing solid state refrigeration by spin-crossover materials.

<p>You can find a short introduction to spin-crossover and its applications is in&nbsp;<em>Chemical Communications</em> <strong>2013</strong>, <em>49</em>, 10890.</p>

<p><strong>EPSRC Doctoral Training Partnership 2024/25</strong></p> <p>Formal applications for research degree study should be made online through the&nbsp;<a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University&#39;s website</a>. Please state clearly in the Planned Course of Study section that you are applying for&nbsp;<em><strong>EPSRC DTP Engineering &amp; Physical Sciences</strong></em>&nbsp;(if you do not apply to this programme code, your application will not be considered) and in the research information section&nbsp;that the research degree you wish to be considered for is&nbsp;<em><strong>Spin-crossover compounds &ndash; switchable materials from simple metal complexes</strong></em>&nbsp;as well as <a href="https://physicalsciences.leeds.ac.uk/staff/173/professor-malcolm-halcrow">Professor Malcolm Halcrow</a> as your proposed supervisor. Please state in the Finance section that the funding source you are applying for is&nbsp;<em><strong>EPSRC Doctoral Training Partnership 2024/25: Chemistry</strong></em>.</p> <p><strong>All other funding sources/self-funded/externally sponsored</strong></p> <p>Formal applications for research degree study should be made online through the&nbsp;<a href="https://www.leeds.ac.uk/info/130206/applying/91/applying_for_research_degrees">University&#39;s website</a>. Please state clearly in the Planned Course of Study that you are applying for <em><strong>PHD Chemistry FT,</strong></em>&nbsp;in the research information section&nbsp;that the research degree you wish to be considered for is <em><strong>Spin-crossover compounds &ndash; switchable materials from simple metal complexes</strong></em>&nbsp;as well as <a href="https://physicalsciences.leeds.ac.uk/staff/173/professor-malcolm-halcrow">Professor Malcolm Halcrow</a> as your proposed supervisor. Please state in the Finance section the&nbsp;<em><strong>funding source you are applying for, if you are self-funding or if you are externally sponsored (please incude the name of your sponsor)</strong></em>.</p> <p>If English is not your first language, you must provide evidence that you meet the University&#39;s minimum English language requirements (below).</p> <p style="margin-bottom:11px"><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p> <p class="MsoNoSpacing">Applications will be considered after the closing date. &nbsp;Potential applicants are strongly encouraged to contact the supervisors for an informal discussion before making a formal application. We also advise that you apply at the earliest opportunity as the application and selection process may close early, should we receive a sufficient number of applications or that a suitable candidate is appointed.</p> <p>Please note that you must provide the following documents in support of your application by the closing date of 3 April 2024 for Leeds Opportunity Research Scholarship, 8 April 2024 for Leeds Doctoral Scholarship or 29 April 2024 for EPSRC DTP:</p> <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> </ul>

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<p><strong>UK Only</strong></p> <p>A highly competitive EPSRC Doctoral Training Partnership Studentship offering the award of fees, together with a tax-free maintenance grant of &pound;19,237 per year for 3.5 years.&nbsp; Training and support will also be provided.</p> <p>This opportunity is open to UK applicants only.&nbsp; All candidates will be placed into the EPSRC Doctoral Training Partnership Studentship Competition and selection is based on academic merit.</p> <p>The&nbsp;<a href="https://phd.leeds.ac.uk/funding/209-leeds-doctoral-scholarships-2022">Leeds Doctoral Scholarships</a> and <a href="https://phd.leeds.ac.uk/funding/234-leeds-opportunity-research-scholarship-2022">Leeds Opportunity Research Scholarship</a> are available to UK applicants (open from October 2023). <a href="https://phd.leeds.ac.uk/funding/60-alumni-bursary">Alumni Bursary</a> is available to graduates of the University of Leeds.</p> <p>Please refer to the&nbsp;<a href="https://www.ukcisa.org.uk/">UKCISA</a>&nbsp;website for&nbsp;information regarding Fee Status for Non-UK Nationals.</p> <p><strong>Self-Funded or externally sponsored students are welcome to apply.</strong></p> <p><strong>Non-UK</strong> &ndash;The&nbsp;<a href="https://phd.leeds.ac.uk/funding/48-china-scholarship-council-university-of-leeds-scholarships-2021">China Scholarship Council - University of Leeds Scholarship</a>&nbsp;is available to nationals of China (now closed for 2024/25 entry). The&nbsp;<a href="https://phd.leeds.ac.uk/funding/73-leeds-marshall-scholarship">Leeds Marshall Scholarship</a>&nbsp;is available to support US citizens. <a href="https://phd.leeds.ac.uk/funding/60-alumni-bursary">Alumni Bursary</a> is available to graduates of the University of Leeds.</p> <p><strong>Important:</strong>&nbsp; Any costs associated with your arrival at the University of Leeds to start your PhD including flights, immigration health surcharge/medical insurance and Visa costs are <strong>not </strong>covered under these studentships.</p> <p>Please refer to the <a href="https://www.ukcisa.org.uk/">UKCISA</a> website for information regarding Fee Status for Non-UK Nationals.</p>

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