C−H and C−S Bond Cleavage in Uranium(III) Thiolato Complexes

Reduction of the uranium(IV) thiolates Cp*₂U(SR)₂ (Cp* = η-C₅Me₅, R = Ph, Me, ⁱPr or ^tBu) with sodium amalgam afforded the corresponding U(III) complexes Na[Cp*₂U(SR)₂] (R = Ph, 2a; Me, 2b; ⁱPr, 2c) or the U(IV) sulfide Na[Cp*₂U(S^tBu)(S)]. C−S bond cleavage of a thiolate ligand was also observed during the thermal decomposition of 2c into the sulfide Na[Cp*₂U(SⁱPr)(S)], whereas 2b was transformed in refluxing THF into the thiametallacyclopropane complex Na[Cp*₂U(SMe)(SCH₂)], resulting from C−H bond activation of a SMe group. The X-ray crystal structures of [Na(18-crown-6)(THF)₂][Cp*₂U(SⁱPr)₂], [Na(18-crown-6)][Cp*₂U(S^tBu)(S)], and [Na(18-crown-6)(THF)₂][Cp*₂U(SMe)(SCH₂)] have been determined.