Actinocene
An actinocene is a type of organoactinide metallocene compound that contains an element from the actinide series. The typical structure is a sandwich compound, with two cyclooctatetraenyl dianions (cot, which is C
8H2−
8) bound to an actinide-metal center (An) in the oxidation state IV, with the resulting general formula An(C8H8)2[1]
The most studied actinocene is uranocene, U(C8H8)2.[2]
The actinide-cyclooctatetraenyl bonding was shown by computational chemistry to be mainly due to mixing of actinide 6d orbitals into ligand π-orbitals and therefore donation of electronic charge to the actinide, with a smaller such interaction involving the actinide 5f orbitals. [3]
Other actinocenes include protactinocene (Pa(C8H8)2), thorocene (Th(C8H8)2), neptunocene (Np(C8H8)2), and plutonocene (Pu(C8H8)2).
Sandwiched M(C8H8)2 compounds (actinocenes and lanthanocenes) exist for M = Nd, Tb, Pu, Pa, Np, Th, U and Yb.[2]
References
- Minasian, Stefan G.; Keith, Jason M. (2014). "New evidence for 5f covalency in actinocenes determined from carbon K-edge XAS and electronic structure theory" (PDF). Chem. Sci. 5 (1): 351–359. doi:10.1039/C3SC52030G.
- Seyferth, D. (2004). "Uranocene. The First Member of a New Class of Organometallic Derivatives of the f Elements". Organometallics. 23 (15): 3562–3583. doi:10.1021/om0400705.
- Kerridge, Andrew (2014). "f-Orbital covalency in the actinocenes (An = Th–Cm): multiconfigurational studies and topological analysis" (PDF). RSC Advances. 4: 12078–12086. doi:10.1039/C3RA47088A.