Organolanthanide chemistry
Encyclopedia
Organolanthanide chemistry is the field of chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

 that studies compounds with a lanthanide-to-carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

 bond.

Background

With the exception of lutetium, all lanthanides belong to the f block. At room temperature, they are shiny metals that usually corrode easily (europium
Europium
Europium is a chemical element with the symbol Eu and atomic number 63. It is named after the continent of Europe. It is a moderately hard silvery metal which readily oxidizes in air and water...

, for example, corrodes in air to form an oxide within seconds.) Most of them tend to be powerful reducing agents and can readily reduce transition metal
Transition metal
The term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some...

 compounds to the pure metals. Lanthanum
Lanthanum
Lanthanum is a chemical element with the symbol La and atomic number 57.Lanthanum is a silvery white metallic element that belongs to group 3 of the periodic table and is the first element of the lanthanide series. It is found in some rare-earth minerals, usually in combination with cerium and...

, for instance, has a reactivity comparable to magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

 with a reduction potential of -2.37 V
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...

 for the reaction:
  • La3+ + 3e- → La


Organolanthanide compounds are different from their d-block
D-block
The d-block is the portion of the periodic table that contains the element groups 3-12. These groups correspond to the filling of the atomic d-orbital subshell, with electron configurations ranging from s2d1 to s2d10...

 cousins in the following ways:
  • They are far more air- and water-sensitive and are often pyrophoric.
  • Chemistry in the 0 oxidation state
    Oxidation state
    In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...

     is far more limited. In fact, their electropositive nature makes their organometallic compounds more likely to be ionic.
  • They form no stable carbonyl
    Carbonyl
    In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups....

    s at room temperature; organolanthanide carbonyl compounds have been observed only in argon
    Argon
    Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...

     matrices, and decompose when heated to 40 K
    Kelvin
    The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

    .

Alkyl reactions

Metal-carbon σ bonds are found in alkyls of the lanthanide elements such as [LnMe6]3- and Ln[CH(SiMe3)3]. Methyllithium dissolved in THF
ThF
Follicular B helper T cells , are antigen-experienced CD4+ T cells found in the B cell follicles of secondary lymphoid organs such as lymph nodes, spleens and Peyer's patches, and are identified by their constitutive expression of the B cell follicle homing receptor CXCR5...

 reacts in stoichiometric ratio with LnCl3 (Ln = Y
Yttrium
Yttrium is a chemical element with symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and it has often been classified as a "rare earth element". Yttrium is almost always found combined with the lanthanides in rare earth minerals and is...

, La
Lanthanum
Lanthanum is a chemical element with the symbol La and atomic number 57.Lanthanum is a silvery white metallic element that belongs to group 3 of the periodic table and is the first element of the lanthanide series. It is found in some rare-earth minerals, usually in combination with cerium and...

) to yield Ln(CH3)3 probably contaminated with LiCl
Lithium chloride
Lithium chloride is a chemical compound with the formula LiCl. The salt is a typical ionic compound, although the small size of the Li+ ion gives rise to properties not seen for other alkali metal chlorides, such as extraordinary solubility in polar solvents and its hygroscopic...

.

If a chelating agent (L-L), such as tetramethylethylenediamine
Tetramethylethylenediamine
Tetramethylethylenediamine is a chemical compound with the formula 2NCH2CH2N2. This species is derived from ethylenediamine by replacement of the four N-H groups with four N-methyl groups. Its odor is remarkably similar to that of fish.-As a reagent in organic and inorganic synthesis:TMEDA is...

 (tmed ortmeda) 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].

Aryls

Certain powdered lanthanides react with diphenylmercury
Diphenylmercury
Diphenylmercury is a colourless, crystalline organomercury compound with the chemical formula C12H10Hg. It can be synthesised by the reaction of a 2:1 molar ratio of mercury chloride and methyltriphenyltin in ethanol...

 in THF to yield octahedral complexes:
  • 2Ln + 3Ph2Hg + 6THF → 2LnPh3(THF)3 + Hg (Ln = Ho
    Holmium
    Holmium is a chemical element with the symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a rare earth element. Its oxide was first isolated from rare earth ores in 1878 and the element was named after the city of Stockholm....

    , Er
    Erbium
    Erbium is a chemical element in the lanthanide series, with the symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements on Earth...

    , Tm
    Thulium
    Thulium is a chemical element that has the symbol Tm and atomic number 69. Thulium is the second least abundant of the lanthanides . It is an easily workable metal with a bright silvery-gray luster...

    , Lu).
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