Abstract
Molecular thorium complexes are dominated by stable tetravalent thorium, while subvalent thorium and the relevant synthons are very limited. Herein, we report that hydrogenolysis of the half-sandwich penta-arylcyclopentadienyl-supported thorium tribenzyl complex [(Cp(Ar5))Th(p-CH(2)-C(6)H(4)-Me)(3)] (1) (Cp(Ar5) = C(5)Ar(5), Ar = 3,5-(i)Pr(2)-C(6)H(3)) affords the double-sandwich bimetallic hydride complex [(Cp(Ar5))Th(μ-H)](2) (2), in which one of the five aryl groups in the Cp(Ar5) ligand is selectively reduced to a puckered di-anionic 1,4-cyclohexadienyl. Complex 2 can be regarded as a thorium(ii) hydride synthon, and exhibits unique redox-active reactivity towards various substrates. Complex 2 not only serves as the six-electron transfer reagent in the reduction of Te and N(3)SiMe(3), leading to the formation of [(Cp(Ar5))Th(THF)](2)(μ-Te)(3) (3) and [(Cp(Ar5))Th(μ-N(3))(μ-NSiMe(3))](2) (4), but also promotes the four-electron reductive coupling of CS(2) and benzonitrile accompanied by Th-H addition, resulting in the isolation of [(Cp(Ar5))Th(μ-η(2):η(2)-CS(3))(μ-S)(μ-η(4):η(1)-SCH[double bond, length as m-dash]CHS)Th(Cp(Ar5))] (5) and [(Cp(Ar5))Th(PhCN)(2)(μ-NCH(2)Ph){η(1),κ(3)-NC(Ph)[double bond, length as m-dash]C(Ph)NC(Ph)[double bond, length as m-dash]NC(Ph)[double bond, length as m-dash]N}Th(Cp(Ar5))] (6) respectively.