Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far
In accordance with Annex 1, we have achieved the following goals at the mid-term report stage:
Work-package 1
The targeted synthesis of dimetallic and trimetallic lanthanide complexes has been achieved. We are able to modify the steric properties of capping and bridging ligands in order to target di- and tri-metallic SMMs with bridging phosphorus and sulphur ligands.
The initial WP1 SMMs have been characterized and their magnetic properties understood. Enhancement of the SMM properties can now be achieved synthetically by, e.g. changing donor atom, lanthanide or capping ligands.
Following on from the above, we have also characterized a series of novel sulphur radicals as their potassium salts. This places us in a strong position to move forward with the next stage of WP1, which is to transfer the radical ligands to the coordination environment of a lanthanide.
Work-package 2.1
Synthetic routes to a series of Ln3HAT complexes have been developed. Radical-bridged versions have been developed. The next step is to extend this to derivatives with control over ligand spin.
We have developed an understanding of the reasons why SMMs such as those studied in WP2 show slow relaxation of the magnetization. This approach involved the development of a novel magneto-structural correlation in which the magnetic axiality of SMMs containing the [Cp2Dy]+ functional unit was proposed for the first time. An important output from these results is a firm link between WP2 and WP1 since the common factor is the [Cp2Dy]+ magnetic building block. As a result, we have clear synergies between the two work packages, hence developments with one will inform developments with the other. Moving forward at the mid-point of the project, we are now in a firm position to extend the initial findings and use them to develop and understand a wide range of the originally proposed radical-bridged SMMs in WP2.
The PI has established organometallic chemistry as a highly effective synthetic method for the synthesis of single-molecule magnets. This methodology has now been adopted by meaning leading researchers in the field, and it is responsible for many of the most exciting developments moving forward. The project has established that strict axial molecular symmetry is not necessary for good SMM performance.
The PI’s axial metallocene theory of SMMs has delivered the first and (to date) only SMM that functions above the boiling point of liquid nitrogen. This is a landmark result that defines the state-of-the-art.
The most important findings from the project have attracted the interest of the physics and materials science communities, including experimental and theoretical groups. This demonstrates that, although chemistry is at the heart of the project, it is truly multidisciplinary in nature.
