C-H and C-S bond cleavage in uranium(III) thiolato complexes

Reduction of the uranium(IV) thiolates Cp*U-2(SR)(2) (Cp* = eta -C5Me5, R = Ph, Me, Pr-i or Bu-t) with sodium amalgam afforded the corresponding U(III) complexes Na[Cp*U-2(SR)(2)] (R = Ph, 2a; Me, 2b; Pr-i, 2c) or the U(IV) sulfide Na[Cp*U-2((SBu)-Bu-t)(S)]. C-S bond cleavage of a thiolate ligand was also observed during the thermal decomposition of 2c into the sulfide Na[Cp*U-2((SPr)-Pr-i)(S)], whereas 2b was transformed in refluxing THF into the thiametallacyclopropane complex Na[Cp*U-2(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*U-2((SPr)-Pr-i)(2)], [Na(18-crown-6)] [Cp*U-2((SBu)-Bu-t)(S)], and [Na(18-crown-6)(THF)(2)][Cp*U-2(SMe)(SCH2)] have been determined.