2.2.2-Cryptand

2.2.2-Cryptand

2.2.2-Cryptand

Chemical compound

The correct title of this article is [2.2.2]Cryptand. The omission of any brackets is due to technical restrictions.

[2.2.2]Cryptand is the organic compound with the formula N(CH2CH2OCH2CH2OCH2CH2)3N. This bicyclic molecule is the most studied member of the cryptand family of chelating agents.[2] It is a white solid. Many analogous compounds are known. Their high affinity for alkali metal cations illustrates the advantages of "preorganization", a concept within the area of supramolecular chemistry.

Quick Facts Names, Identifiers ...

For the design and synthesis of [2.2.2]cryptand,[3] Jean-Marie Lehn shared the Nobel Prize in Chemistry. The compound was originally prepared starting with the diacylation of the diamine-diether:[4]

[CH2OCH2CH2NH2]2 + [CH2OCH2COCl]2 → [CH2OCH2CH2NHC(O)CH2]2 + 2 HCl

The resulting macrocyclic diamide is reduced by lithium aluminium hydride. The resulting macrocyclic diamine tetraether reacts with a second equivalent of [CH2OCH2COCl]2 to produce the macrobicyclic diamide. This di(tertiary)amide is reduced to the diamine by diborane.

[2.2.2]Cryptand binds K+ as an octadentate N2O6 ligand. The resulting cation K([2.2.2]cryptand)+ is lipophilic.

Structure of [2.2.2]cryptand encapsulating a potassium cation (purple) as determined by X-ray crystallography[5]

References

  1. [1]
    In the Nomenclature of Inorganic Chemistry (2005), IUPAC recommends the abbreviation crypt-222.
  2. [2]
    Kang, Sung Ok; Llinares, José M.; Day, Victor W.; Bowman-James, Kristin (2010). "Cryptand-like anion receptors". Chemical Society Reviews. 39 (10): 3980–4003. doi:10.1039/C0CS00083C. PMID 20820597.
  3. [3]
    Dietrich, B.; Lehn, J.M.; Sauvage, J.P. (1969). "Les Cryptates". Tetrahedron Letters. 10 (34): 2889–2892. doi:10.1016/S0040-4039(01)88300-3.
  4. [4]
    Dietrich, B.; Lehn, J.M.; Sauvage, J.P. (1969). "Diaza-polyoxa-macrocycles et macrobicycles". Tetrahedron Letters. 10 (34): 2885–2888. doi:10.1016/S0040-4039(01)88299-X.
  5. [5]
    Alberto, R.; Ortner, K.; Wheatley, N.; Schibli, R.; Schubiger, A. P. (2001). "Synthesis and properties of boranocarbonate: a convenient in situ CO source for the aqueous preparation of [99mTc(OH2)3(CO)3]+". J. Am. Chem. Soc. 121 (13): 3135–3136. doi:10.1021/ja003932b. PMID 11457025.
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