Actinide tetra-N-heterocyclic carbene ‘sandwiches’

摘要: Highly-symmetrical, thorium and uranium octakis-carbene ‘sandwich’ complexes have been prepared by ‘sandwiching’ the An(IV) cations between two anionic macrocyclic tetra-NHC ligands, one with sixteen atoms other eighteen atoms. The were characterized a range of experimental methods DFT calculations. X-ray crystallography confirms geometry at metal centre can be set size ring, leading to either square prismatic or anti-prismatic shapes; latter is retained in solution, which also undergoes reversible, electrochemical one-electron oxidation reduction for variant. calculations reveal frontier orbital picture that similar thorocene uranocene, NHC ligands show almost exclusively σ-donation without π-backbonding.