Cerocene

Cerocene
Names
IUPAC name
Bis(η8-cyclooctatetraene)cerium
Other names
Cerium di-cyclooctatraene
Identifiers
3D model (JSmol)
  • Key: XMGBAYFIOLSVIM-YTBUGUEYSA-N
  • InChI=1S/2C8H6.Ce/c2*1-2-4-6-8-7-5-3-1;/h2*1-3,6-8H;/q2*-2;+4/b2*2-1-,3-1?,8-6?,8-7-;
  • C\1=C\[C-]=C/C=C\[C-]=C1.C\1=C\[C-]=C/C=C\[C-]=C1.[Ce+4]
Properties
Ce(C8H8)2
Molar mass 348.423
Appearance red crystal
Melting point 290 °C (With Decomposition)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Cerocene is a organometallic complex with the chemical formula Ce(C8H8)2 (Ce(cot)2). It is a sandwich compound consisting of a central cerium atom and two cyclooctatetraenide rings.

Preparation

Cerocene can be prepared by reducing cerium(III) di-cyclooctatraene anion salts:

Ce(C8H8)2K → Ce(C8H8)2 + K+

Chemical properties

Cerocene decomposes when exposed to water or oxygen to yield non-stoichiometric cerium-oxides and cyclooctratraene derivitives.

It undergoes a disproportionation, leading to an equilibrium between cerocene and a double-decker structure containing two cerium atoms:

2 Ce(C8H8)2 ⇌ Ce2(C8H8)3 + C8H8

Although the cyclooctatetraenide ligand is usually considered a dianion and therefore cerocene is identified as a Ce(IV) complex, theoretical and experimental analysis of the compound indicates that is more correctly described containing a Ce(III) atom.

Cerocene is a known precursor for uranocene, U(C8H8)2:

Ce(C8H8)2 + UCl3 ⇌ U(C8H8)2 + CeCl3

Cerocene is commonly confused with the compound tris(cyclopentadienyl)cerium.

References

  1. 1 2 3 4 Streitwieser, Andrew; Kinsley, Steven A.; Jenson, Chris Henry; Rigsbee, John T. (2004-10-01). "Synthesis and Properties of Di-π-[8]annulenecerium(IV), Cerocene". Organometallics. 23 (22): 5169–5175. ISSN 0276-7333.
  2. 1 2 3 Walter, Marc D.; Booth, Corwin H.; Lukens, Wayne W.; Andersen, Richard A. (2009). "Cerocene Revisited: The Electronic Structure of and Interconversion Between Ce2(C8H8)3and Ce(C8H8)2". Organometallics. 28 (3): 698–707. doi:10.1021/om7012327. OSTI 948446.