1,1'-Dilithioferrocene

1,1'-Dilithioferrocene is the organoiron compound with the formula Fe(C5H4Li)2. It is exclusively generated and isolated as a solvate, using either ether or tertiary amine ligands bound to the lithium centers. Regardless of the solvate, dilithioferrocene is used commonly to prepare derivatives of ferrocene.

1,1'-Dilithioferrocene
Names
IUPAC name
1,1'-Dilithioferrocene
Identifiers
3D model (JSmol)
  • InChI=1S/2C5H4.Fe.2Li/c2*1-2-4-5-3-1;;;/h2*1-4H;;;/q2*-1;;2*+1
    Key: CWUATGTYNYDRDF-UHFFFAOYSA-N
  • [Li+].[Li+].[CH]1[CH][CH][C-][CH]1.[CH]1[CH][CH][C-][CH]1.[Fe]
Properties
C10H8FeLi2
Molar mass 197.90 g·mol−1
Appearance orange solid
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 pyrophoric
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Synthesis and reactions

Treatment of ferrocene with butyl lithium gives 1,1'-dilithioferrocene, regardless of the stoichiometry (monolithioferrocene requires special conditions for its preparation). Typically the lithiation reaction is conducted in the presence of tetramethylethylenediamine (tmeda). The adduct [Fe(C5H4Li)2]3(tmeda)2 has been crystallized from such solutions.[1] Recrystallization of this adduct from thf gives [Fe(C5H4Li)2]3(thf)6.[2]

1,1'-Dilithioferrocene reacts with a variety of electrophiles to afford disubstituted derivatives of ferrocene. These electrophiles include S8 (to give 1,1'-ferrocenetrisulfide), chlorophosphines, and chlorosilanes.[3]

Some transformations of dilithioferrocene.

The diphosphine ligand 1,1'-bis(diphenylphosphino)ferrocene (dppf) is prepared by treating dilithioferrocene with chlorodiphenylphosphine.

Monolithioferrocene

The reaction of ferrocene with one equivalent of butyllithium mainly affords dilithioferrocene. Monolithioferrocene can be obtained using tert-butyllithium.[4]

References
  1. Butler, Ian R.; Cullen, William R.; Ni, Jijin; Rettig, Stephen J. (1985). "The Structure of the 3:2 Adduct of 1,1'-Dilithioferrocene with Tetramethylethylenediamine". Organometallics. 4 (12): 2196–2201. doi:10.1021/om00131a023.
  2. Perucha, Alejandro Sánchez; Heilmann-Brohl, Julia; Bolte, Michael; Lerner, Hans-Wolfram; Wagner, Matthias (2008). "Comparison of Doubly Lithiated, Magnesiated, and Zincated Ferrocenes: [Fe(η5-C5H4)2]2Zn2(tmeda)2, the First Example of a [1.1]Ferrocenophane with Bridging First-Row Transition Metal Atoms". Organometallics. 27 (23): 6170–6177. doi:10.1021/om800765a.
  3. Herbert, David E.; Mayer, Ulrich F. J.; Manners, Ian (2007). "Strained Metallocenophanes and Related Organometallic Rings Containing pi-Hydrocarbon Ligands and Transition-Metal Centers". Angew. Chem. Int. Ed. 46 (27): 5060–5081. doi:10.1002/anie.200604409. PMID 17587203.
  4. Rautz, Hermann; Stüger, Harald; Kickelbick, Guido; Pietzsch, Claus (2001). "Synthesis, Structural Characterization and 57Fe-Mössbauer Spectra of Ferrocenylhexasilanes". Journal of Organometallic Chemistry. 627 (2): 167–178. doi:10.1016/S0022-328X(01)00743-4.
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