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

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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.