Synthesis and X-ray crystal structure of [Na(18-crown-6)][U(Cp*)2(SBut)(S)], the first f-element compound containing a metal–sulfur double bond

The C–S bond cleavage of a thiolate ligand of [U(Cp*)2(SBut)2] was induced by treatment with Na(Hg) and the title compound was isolated after addition of 18-crown-6; the crystal structure exhibited the unsupported U–S–Na linkage of the molecular complex, with a U–S bond distance of 2.462(2) Å.