Ring-opening of a thorium cyclopropenyl complex generates a transient thorium-bound carbene

The reaction of [Cp3ThCl] with in situ generated 1-lithium-3,3-diphenylcyclopropene results in the formation of [Cp3Th(3,3-diphenylcyclopropenyl)] (1), in good yields. Thermolysis of 1 results in isomerization to the ring-opened product, [Cp3Th(3-phenyl-1H-inden-1-yl)] (3) via a hypothesized carbene intermediate. This transformation represents a new mode of reactivity of 3,3-diphenylcyclopropene with the actinides, improving our ability to use this reagent as a carbene source. A combined DFT and C-13(H-1) NMR analysis of 1 shows a spin-orbit induced downfield shift at C-alpha due to participation of the 5f orbitals in the Th-C bond.

Automated summary

The reaction of [Cp3ThCl] with in situ generated 1-lithium-3,3-diphenylcyclopropene leads to the formation of [Cp3Th(3,3-diphenylcyclopropenyl)] (1), with good yields. Thermolysis of 1 results in isomerization to the ring-opened product, [Cp3Th(3-phenyl-1H-inden-1-yl)] (3) via a hypothesized carbene intermediate. This transformation represents a new reactivity mode of 3,3-diphenylcyclopropene with actinides, enhancing its utility as a carbene source. A combined DFT and C-13(H-1) NMR analysis of 1 reveals a spin-orbit induced downfield shift at C-alpha due to the involvement of 5f orbitals in the Th-C bond.