A Structurally Characterized Organometallic Plutonium(IV) Complex

Abstract

The blood-red plutonocene complex Pu(1,3-COT'')(1,4-COT'')(4;COT'' = h 8 -bis(trimethylsilyl)cyclooctatetraenyl) has been synthesized by oxidation of the anionic sandwich complex Li[Pu(1,4-COT'') 2 ]( 3)w ith anhydrous cobalt(II) chloride.The first crystal structure determination of an organoplutonium(IV) complex revealed an asymmetric sandwich structure for 4 where one COT'' ring is 1,3substituted while the other retains the original 1,4-substitution pattern. The electronic structure of 4 has been elucidated by ac omputational study,r evealing ap robable cause for the unexpected silyl group migration.Supportinginformation, includingexperimental procedures,crystallographic and computational details, and the ORCID identification number(s) for the author(s) of this article can be found under: http://dx.

Organometallic Neptunium Chemistry

“…The early An sandwich complexes are isostructural and their geometric data can be directly compared with that of neptunocene. Upon progressing from Th to Np, no real pattern appears in the C–C bond lengths of the COT ligand, but the An–ring centroid distance decreases from Th (2.0036(5) Å) to U (1.9264(5) Å) and to Np (1.9088(3) Å). , Very recently the structure of Pu­(1,3-COT″)­(1,4-COT″) (COT″ = C 8 H 6 (SiMe 3 ) 2 ) has been reported; the An–ring centroid distances are 1.89 and 1.90 Å. A computational analysis was also undertaken in order to suggest the reason for an unanticipated ring-migration of one of the silyl substituents.…”

“…Combined synthetic/spectroscopic/computational reports are demonstrating with increasing frequency how, in the absence of protic and hydrolyzable ligands and solvents, discrete molecular complexes in a variety of formal oxidation states, with covalently binding, organometallic ligands that form actinide-ligand σ-, π-, δ-, and even ϕ-(back)­bonding interactions, provide an excellent platform for advancing the fundamental understanding of the differences in orbital contributions and covalency in f-block metal–ligand bonding. , For example, recent quantitative carbon K-edge X-ray absorption spectroscopy (XAS) analyses on the organometallic actinocenes An­(COT) 2 (An = Th, U; COT = η-C 8 H 8 ) provided the first experimental evidence for extensive ϕ-orbital interactions in thorocene [observation of a C 1s to Th–C antibonding 2e 3u (5f-ϕ)] and remarkably little in the U analogue (where the interaction is better with the 2e 2u ), providing an important caveat that different orbitals will not necessarily show the same trends in orbital mixing across the actinide series . Different behavior is seen again for the electronic structure of the recently reported plutonocene derivative Pu­(1,3-COT″)­(1,4-COT″) [COT″ = η-C 8 H 6 (SiMe 3 ) 2 ] . Neptunium is also a very sensitive nucleus for Mössbauer spectroscopic studies of the electronic influences of ligand bonding on a Np cation.…”

Actinide Organometallic Complexes with π‐Ligands

“…However for Pu there is actually reported only one single crystal structure determined on the substituted Pu IV actinocene {Pu[COT(SiMe 3 ] 2 ) 2 } (Table ) . The comparable actinide complexes of Th and U are listed in Table as well .…”