Oxide is an attractive linker for building polymetallic complexes that provide molecular models for metal oxide activity, but studies of these systems are limited to metals in high oxidation states. Herein, we synthesized and characterized the molecular and electronic structure of diuranium bridged UIII/UIV and UIII/UIII complexes. Reactivity studies of these complexes revealed that the U−O bond is easily broken upon addition of N‐heterocycles resulting in the delivery of a formal equivalent of UIII and UII, respectively, along with the uranium(IV) terminal‐oxo coproduct. In particular, the UIII/UIII oxide complex effects the reductive coupling of pyridine and two‐electron reduction of 4,4′‐bipyridine affording unique examples of diuranium(III) complexes bridged by N‐heterocyclic redox‐active ligands. These results provide insight into the chemistry of low oxidation state metal oxides and demonstrate the use of oxo‐bridged UIII/UIII complexes as a strategy to explore UII reactivity.

The redox chemistry of uranium is dominated by single electron transfer reactions while single metal four-electron transfers remain unknown in f-element chemistry. Here we show that the oxo bridged diuranium(III)...

The tuning of metal-metal interactions in multinuclear assemblies is a challenge. Selective P coordination of a redox-active PNO ligand to Au(I) followed by homoleptic metalation of the NO pocket with Ni(II) affords a unique trinuclear Au-Ni-Au complex. This species features two antiferromagnetically coupled ligand-centered radicals and a double intramolecular d(8)-d(10) interaction, as supported by spectroscopic, single-crystal X-ray diffraction, and computational data. A corresponding cationic dinuclear Au-Ni analogue with a stronger d(8)-d(10) interaction is also reported. Although both heterobimetallic structures display rich electrochemistry, only the trinuclear Au-Ni-Au complex facilitates electrocatalytic C-X bond activation of alkyl halides in its doubly reduced state. Hence, the presence of a redox-active ligand framework, an available coordination site at gold, and the nature of the nickel-gold interaction appear to be essential for this reactivity.