The Jenkins Group published their work “Imidazolinium N-Heterocyclic Carbene Ligands for Enhanced Stability on Gold Surfaces” in Langmuir. This work explores the preparation and stability of NHC-coated gold surfaces using imidazolium and imidazolinium NHC ligands. X-ray photoelectron spectroscopy and surface-enhanced Raman spectroscopy demonstrate the attachment of NHC ligands to the gold surface and show enhanced stability of imidazolinium compared to the traditional imidazolium under harsh acidic conditions.
The Jenkins Group also published their work “Actinide tetra-N-heterocyclic carbene ‘sandwiches’” in Chemical Science. “We synthesized new “sandwich” complexes by placing two NHC macrocycles around a single actinide ion,” Jenkins said. “I am particularly excited about this paper since it is work that I began on my sabbatical at the University of Edinburgh almost four years ago. It is the beginning of a new research area in my group, which is f-block NHC chemistry.”
The complexes were characterized by a range of experimental methods and DFT calculations. X-ray crystallography confirms the geometry at the metal centre can be set by the size of the macrocyclic ring, leading to either square prismatic or square anti-prismatic shapes; the geometry of the latter is retained in solution, which also undergoes reversible, electrochemical one-electron oxidation or reduction for the uranium variant. DFT calculations reveal a frontier orbital picture that is similar to thorocene and uranocene, in which the NHC ligands show almost exclusively σ-donation to the metal without π-backbonding.