ACTINIDES

Organometallics

• Organometallic chemistry of actinides is relatively recent
• Similar to lanthanides in range of cyclopentadienides / cyclooctatetraenides / alkyls
• Cyclopentadienides are p-bonded to actinides.

  Compounds include:-

  

  C₅H₅^- does not behave ionically

  but Cl^- is labile: Þ formation of a wide variety of (C₅H₅)₃UX compounds

• The most notable Cyclooctatetraenide is Uranocene

  

• Green crystals
• Paramagnetic
• Pyrophoric
• Stable to hydrolysis
• Planar 'sandwich'
• Eclipsed D_8h conformation
• UV-PES studies show that bonding in uranocene has 5f & 6d contributions
  • e_2u symmetry interaction shown can only occur via f-orbitals
  • See: C. Elschenbroich & A. Salzer, Organometallics, 2nd ed.VCH, Weinheim, 1992 p. 363-5