Triscyclopentadienyl uranium thiolates and selenolates

Triscyclopentadienyl uranium (IV) thiolates were prepared by two principal methods namely (1) substitution of the chloride group of [U(cp)(3)(Cl)] (cp=eta-C5H5) by SR(-) and (2) oxidation of the trivalent precursors [U(cp)(3)(THF)] (THF=tetrahydrofuran), [U(C(5)H(4)SiMe(3))(3)] and [U(C(5)H(4)(t)Bu)(3)] with the disulfide RSSR (R = Me, Et,Pr-i,(t)Bu or Ph). Similar treatment with MeSeSeMe afforded [U(cp)(3)(SeMe)] and [U(C(5)H(4)SiMe(3))(3)(SeMe)]. The crystal structure of [U(cp)(3)(SMe)] was determined. Several reactions of these complexes are described, namely cleavage of the U-S bond by acidic substrates or iodine, insertion of CS2 and CO2 into the U-S bond, and reduction into the corresponding U(III) anions. The synthesis, structure and reactivity of the thiolate compounds are compared with those of the alkoxide analogues.