Our goal is to investigate the electronic structure and reactivity of uranium-nitrogen and uranium-chalcogen bonds in organometallic uranium-nitride and uranium-chalcogen clusters. The redox chemistry of clusters is interesting, especially because it offers a chance to get more insights about the flow of electrons within and between actinide molecules. New possibilities in multi-electron reduction processes mediated by the actinides may also be revealed by these investigations.
Reaction of (C₅Me₅)U(CH₂C₆H₅)₃ with ammonia produces tetra- and hexanuclear uranium clusters. The products include (C₅Me₅)₄U₄(m₄-N)(m₃-N)₈(H)₁₅, 1, (C₅Me₅)₆U₆(m₆-N)(m-N)₈(H)₁₆, 2, and (C₅Me₅)₆U₆(m₃-N)₂(m-NH)₁₂, 3. Efforts to use stoichiometric amounts of NH₃ (g) or NH₃ (DIOX), gave similar results.
Inspired by these results, we have also sought the preparation of related chalcogen clusters. Reaction of (C₅Me₅)U(CH₂C₆H₅)₃ with HECPh₃ (E = O, S) or E=PPh₃ (E = Se) consistently give the related hexanuclear clusters (C₅Me₅)₆U₆(m₃-O)₂(m-O)₁₂(H)₁₀, 4, (C₅Me₅)₆U₆(m₆-E)(m₃-E)₈ (E = S, 5; Se, 6), respectively.
With these results in hand the spectroscopic, bonding, and redox properties will be further defined. Future efforts will focus on the preparation of other actinide analogs including those of thorium, neptunium, and plutonium.
In my talk, I will be focusing mainly on synthesis and characterization of these clusters.

Ved Prakash

Appearances