Research at The University of Manchester, conducted in collaboration with colleagues at the University of Edinburgh, has explored the electronic structure and bonding of heterobimetallic complexes containing uranium–group 10 metals. The bonds found in this type of molecule are significantly shorter than any other crystallographically characterised d-f-block bimetallic.
Despite the short U–TM (transition metal) distances, the bond orders are calculated by five different approaches to be small; less than 1 in all cases. All bond order metrics are smaller for U–Pd than U–Ni, which agrees with the Quantum Theory of Atoms in Molecules bond critical point data. These findings also agree with population analysis of the U–TM sigma and pi Natural Localised Molecular Orbitals which, while heavily localised on the TM in both cases, are even more so for the 4d system than the 3d, in keeping with the larger electronegativity difference between U and Pd vs. U and Ni.
Overall, the research, which combines spectroscopic, computational, electrochemical, and structural research methods, reveals the U–TM bond strength to lie in the order U–Pt < U–Pd < U–Ni.
- Group 10 metals: Nickel (Ni), Palladium (Pd) and Platinum (Pt)
- Quantum Theory of Atoms-in-Molecules: a computational method for deriving the properties of molecules from the topology of the electron density.
- Natural Localised Molecular Orbitals: a way of representing the electronic structure of a molecule in terms of compact, chemically relevant orbitals localised between two or three atoms.
This work was generously supported by EaStCHEM, the University of Edinburgh, University College London, The University of Manchester, the Engineering and Physical Sciences Research Council and the Austrian Science Fund.