View source for 2.2.2-Cryptand

{{correct title|[2.2.2]Cryptand|reason=bracket|edit=omission}}
{{Chembox
| Name = [2.2.2]Cryptand
| Watchedfields = changed
| verifiedrevid = 477215715
| ImageFile = Cryptand.svg
| ImageName = Skeletal formula of 2.2.2-cryptand
| ImageSize = 150
| ImageFile1 = 2.2.2-Cryptand-3D-balls-by-AHRLS-2012.png 
| ImageSize1 = 150
| ImageFileL2 = 2.2.2-Cryptand-3D-sticks-by-AHRLS-2012.png 
| ImageSizeL2 = 140
| ImageFileR2 = 2.2.2-Cryptand-3D-vdW-by-AHRLS-2012.png 
| ImageSizeR2 = 140
| PIN = 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane
| OtherNames = Cryptating agent 222<ref>In the Nomenclature of Inorganic Chemistry (2005), IUPAC recommends the abbreviation crypt-222.</ref>
|Section1={{Chembox Identifiers
| Abbreviations = Crypt-222
| CASNo = 23978-09-8
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 18V22YHN6G
| PubChem = 72801
| ChemSpiderID = 65637
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| EINECS = 245-962-4
| MeSHName = Cryptating+agent+222
| RTECS = MP4750000
| Beilstein = 620282
| SMILES = C1COCCN2CCOCCOCCN(CCO1)CCOCCOCC2
| StdInChI = 1S/C18H36N2O6/c1-7-21-13-14-24-10-4-20-5-11-25-17-15-22-8-2-19(1)3-9-23-16-18-26-12-6-20/h1-18H2
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| InChI = 1/C18H36N2O6/c1-7-21-13-14-24-10-4-20-5-11-25-17-15-22-8-2-19(1)3-9-23-16-18-26-12-6-20/h1-18H2
| StdInChIKey = AUFVJZSDSXXFOI-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| InChIKey = AUFVJZSDSXXFOI-UHFFFAOYAX
}}
|Section2={{Chembox Properties
| Formula = {{Chem|C|18|N|2|H|36|O|6}}
| MolarMass = 376.4882 g&nbsp;mol<sup>−1</sup>
| MeltingPtC = 68 to 71
}}
|Section3={{Chembox Hazards
| GHSPictograms = {{GHS exclamation mark}}
| GHSSignalWord = '''WARNING'''
| HPhrases = {{H-phrases|315|319|335}}
| PPhrases = {{P-phrases|261|305+351+338}}
}}
}}

'''[2.2.2]Cryptand''' is the [[organic compound]] with the formula N(CH<sub>2</sub>CH<sub>2</sub>OCH<sub>2</sub>CH<sub>2</sub>OCH<sub>2</sub>CH<sub>2</sub>)<sub>3</sub>N. This [[Cyclic molecule|bicyclic]] molecule is the most studied member of the [[cryptand]] family of [[chelating agent]]s.<ref>{{cite journal|last1=Kang|first1=Sung Ok|last2=Llinares|first2=José M.|last3=Day|first3=Victor W.|last4=Bowman-James|first4=Kristin|author-link4=Kristin Bowman-James|year=2010|title=Cryptand-like anion receptors|journal=Chemical Society Reviews|volume=39|issue=10|pages=3980–4003|doi=10.1039/C0CS00083C|pmid=20820597}}</ref> 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]].  

For the design and synthesis of [2.2.2]cryptand,<ref>{{cite journal |doi=10.1016/S0040-4039(01)88300-3|title=Les Cryptates|year=1969|last1=Dietrich|first1=B.|last2=Lehn|first2=J.M.|last3=Sauvage|first3=J.P.|journal=Tetrahedron Letters|volume=10|issue=34|pages=2889–2892}}</ref> [[Jean-Marie Lehn]] shared the [[Nobel Prize in Chemistry]]. The compound was originally prepared starting with the diacylation of the diamine-diether:<ref>{{cite journal |doi=10.1016/S0040-4039(01)88299-X|title=Diaza-polyoxa-macrocycles et macrobicycles|year=1969|last1=Dietrich|first1=B.|last2=Lehn|first2=J.M.|last3=Sauvage|first3=J.P.|journal=Tetrahedron Letters|volume=10|issue=34|pages=2885–2888}}</ref> 
:[CH<sub>2</sub>OCH<sub>2</sub>CH<sub>2</sub>NH<sub>2</sub>]<sub>2</sub>  +  [CH<sub>2</sub>OCH<sub>2</sub>COCl]<sub>2</sub>  →   [CH<sub>2</sub>OCH<sub>2</sub>CH<sub>2</sub>NHC(O)CH<sub>2</sub>]<sub>2</sub>  +  2 HCl
The resulting [[Macrocycle|macrocyclic]] diamide is reduced by [[lithium aluminium hydride]]. The resulting macrocyclic diamine tetraether reacts with a second equivalent of [CH<sub>2</sub>OCH<sub>2</sub>COCl]<sub>2</sub> to produce the macro''bi''cyclic diamide.  This di(tertiary)amide is reduced to the diamine by [[diborane]].

[2.2.2]Cryptand binds [[potassium|K<sup>+</sup>]] as an [[Denticity|octadentate]] N<sub>2</sub>O<sub>6</sub> ligand.  The resulting cation K([2.2.2]cryptand)<sup>+</sup> is lipophilic.

[[Image:Cryptate of potassium cation.jpg|thumbnail|left|Structure of [2.2.2]cryptand encapsulating a [[potassium]] cation (purple) as determined by [[X-ray crystallography]]<ref>{{cite journal |author1=Alberto, R. |author2=Ortner, K. |author3=Wheatley, N. |author4=Schibli, R. |author5=Schubiger, A. P. | title = Synthesis and properties of boranocarbonate: a convenient in situ CO source for the aqueous preparation of [<sup>99m</sup>Tc(OH<sub>2</sub>)<sub>3</sub>(CO)<sub>3</sub>]<sup>+</sup> | journal = [[J. Am. Chem. Soc.]] | year = 2001 | volume = 121 | pages = 3135–3136 | doi = 10.1021/ja003932b |pmid=11457025 | issue = 13}}</ref>]]{{clear-left}}

==References==
{{Reflist}}

{{DEFAULTSORT:Cryptand, 2.2.2-}}
[[Category:Chelating agents]]