Synthesis and Structure of Nitride-Bridged Uranium(III) Complexes

The reduction of the nitride-bridged diuranium­(IV) complex Cs­[{U­(OSi­(O<sup>t</sup>Bu)<sub>3</sub>)<sub>3</sub>}<sub>2</sub>(μ-N)] affords the first example of a uranium nitride complex containing uranium in the +III oxidation state. Two nitride-bridged complexes containing the heterometallic fragments Cs<sub>2</sub>[UIII‐‐‐N‐‐‐UIV] and Cs<sub>3</sub>[UIII‐‐‐N‐‐‐UIII] have been crystallographically characterized. The presence of two or three Cs<sup>+</sup> cations binding the nitride group is key for the isolation of these complexes. In spite of the fact that the nitride group is multiply bound to two uranium and two or three Cs<sup>+</sup> cations, these complexes transfer the nitride group to CS<sub>2</sub> to afford SCN<sup>–</sup> and uranium­(IV) disulfide.