Girish Mahajan (Editor)

Organolanthanide chemistry

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Organolanthanide chemistry is the field of chemistry that studies compounds with a lanthanide-to-carbon bond. Organolanthanide compounds are different from their organotransition metal analogues in the following ways:

Contents

  • They are far more air- and water-sensitive and are often pyrophoric.
  • Chemistry in the 0 oxidation state is far more limited. In fact, their electropositive nature makes their organometallic compounds more likely to be ionic.
  • They form no stable carbonyls at room temperature; organolanthanide carbonyl compounds have been observed only in argon matrices, and decompose when heated to 40 K.

    • σ-Bonded Complexes

    Metal-carbon σ bonds are found in alkyls of the lanthanide elements such as [LnMe6]3− and Ln[CH(SiMe3)2]3. Methyllithium dissolved in THF reacts in stoichiometric ratio with LnCl3 (Ln = Y, La) to yield Ln(CH3)3 probably contaminated with LiCl.

    If a chelating agent (L-L), such as tetramethylethylenediamine (tmed or tmeda) or 1,2-dimethoxyethane (dme) is mixed with MCl3 and CH3Li in THF, this forms [Li(tmed)]3[M(CH3)6] and [Li(dme)]3[M(CH3)6].

    Certain powdered lanthanides react with diphenylmercury in THF to yield octahedral complexes:

    π-Bonded Complexes

    Cyclopentadienyl complexes are known for all lanthanides. All, barring tris(cyclopentadienyl)promethium(III) (Pm(Cp)3) can be produced by the following reaction scheme:

    Pm(Cp)3 can be produced by the following reaction:

    These compounds are of limited use and academic interest.

    References

    Organolanthanide chemistry Wikipedia
    (Text) CC BY-SA