Metal-organic frameworks as platforms for air-stable organometallic single-molecule magnets

Lead Research Organisation: University of Sussex
Department Name: Sch of Life Sciences

Abstract

In 2024, the global data storage industry is predicted to be valued at more than one hundred billion dollars. The technology that currently underpins data storage is based on the memory properties of relatively large magnetic particles: society's need to handle increasingly large amounts of data whilst decreasing the physical size of the storage medium necessitates the discovery of innovative storage methods.

Using sub-nanometre molecules to store magnetic information introduces potential for developing data storage materials that could out-perform conventional technology, responding to the needs of a data-intensive world. The big problems are that the best magnetic molecules available for this challenge function at extremely low temperatures and they decompose on contact with air. We now propose to solve both problems by combining world-leading capability in synthetic chemistry with unique physics expertise and instrumentation in a highly adventurous New Horizons project. By developing a novel approach to making and measuring molecular magnetic materials, we aim to chart a flexible path to the early-stage fabrication of nanoscale magnetic devices based on an unprecedented type of metal-organic composite material, which will consist of single-molecule magnets and metal-organic frameworks, or SMM@MOF materials.

We will also undertake proof-of-concept experiments aimed at preparing thin films of selected SMM@MOF composites. Should we show that SMM@MOF thin films have magnet-like behaviour, the results will form the basis of future research aimed at the fabrication of molecule-based magnetic devices. Success with this project will help to drive the second quantum revolution and provide a platform on which to discover innovative quantum technologies.
 
Description We have found that long-term stability of SMMs in MOFs can be challenging and subject to reactions conditions. Results from this project are currently being prepared for publication.
Exploitation Route Too early.
Sectors Chemicals

 
Title Research data for paper: Identification of oxidation state +1 in a molecular uranium complex 
Description Data for paper published in the Journal of the American Chemical Society. September 2022 X-ray crystallography CIF files, IR data, UV/vis data, magnetic measurement data Abstract The concept of oxidation state plays a fundamentally important role in defining the chemistry of the elements. In the f block of the periodic table, well-known oxidation states in compounds of the lanthanides include 0, +2, +3 and +4, and oxidation states for the actinides range from +7 to +2. Oxidation state +1 is conspicuous by its absence from the f-block elements. Here we show that the uranium(II) metallocene [U(?5-C5iPr5)2] and the uranium(III) metallocene [IU(?5-C5iPr5)2] can be reduced by potassium graphite in the presence of 2.2.2-cryptand to the uranium(I) metallocene [U(?5-C5iPr5)2]- (1) (C5iPr5 = pentaisopropylcyclopentadienyl) as the salt of [K(2.2.2-cryptand)]+. An X-ray crystallographic study revealed that 1 has a bent metallocene structure, and theoretical studies and magnetic measurements confirmed that the electronic ground state of uranium(I) adopts a 5f3(7s/6dz2)1(6dx2-y2/6dxy)1 configuration. The metal-ligand bonding in 1 consists of contributions from uranium 5f, 6d, and 7s orbitals, with the 6d orbitals engaging in weak but non-negligible covalent interactions. Identification of the oxidation state +1 for uranium expands the range of isolable oxidation states for the f-block elements and potentially signposts a synthetic route to this elusive species for other actinides and the lanthanides. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://sussex.figshare.com/articles/dataset/Research_data_for_paper_Identification_of_oxidation_sta...
 
Title Research data for paper: Identification of oxidation state +1 in a molecular uranium complex 
Description Data for paper published in the Journal of the American Chemical Society. September 2022 X-ray crystallography CIF files, IR data, UV/vis data, magnetic measurement data Abstract The concept of oxidation state plays a fundamentally important role in defining the chemistry of the elements. In the f block of the periodic table, well-known oxidation states in compounds of the lanthanides include 0, +2, +3 and +4, and oxidation states for the actinides range from +7 to +2. Oxidation state +1 is conspicuous by its absence from the f-block elements. Here we show that the uranium(II) metallocene [U(?5-C5iPr5)2] and the uranium(III) metallocene [IU(?5-C5iPr5)2] can be reduced by potassium graphite in the presence of 2.2.2-cryptand to the uranium(I) metallocene [U(?5-C5iPr5)2]- (1) (C5iPr5 = pentaisopropylcyclopentadienyl) as the salt of [K(2.2.2-cryptand)]+. An X-ray crystallographic study revealed that 1 has a bent metallocene structure, and theoretical studies and magnetic measurements confirmed that the electronic ground state of uranium(I) adopts a 5f3(7s/6dz2)1(6dx2-y2/6dxy)1 configuration. The metal-ligand bonding in 1 consists of contributions from uranium 5f, 6d, and 7s orbitals, with the 6d orbitals engaging in weak but non-negligible covalent interactions. Identification of the oxidation state +1 for uranium expands the range of isolable oxidation states for the f-block elements and potentially signposts a synthetic route to this elusive species for other actinides and the lanthanides. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://sussex.figshare.com/articles/dataset/Research_data_for_paper_Identification_of_oxidation_sta...
 
Title Research data for paper: Thorium- and Uranium-Mediated C-H Activation of a Silyl-Substituted Cyclobutadienyl Ligand 
Description CIF files and checkcif files for all compounds. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://sussex.figshare.com/articles/dataset/Research_data_for_paper_Thorium-_and_Uranium-Mediated_C...
 
Title Research data for paper: Thorium- and Uranium-Mediated C-H Activation of a Silyl-Substituted Cyclobutadienyl Ligand 
Description CIF files and checkcif files for all compounds. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://sussex.figshare.com/articles/dataset/Research_data_for_paper_Thorium-_and_Uranium-Mediated_C...