15-Crown-5

Last updated
15-Crown-5
15-crown-5 skeletal.svg
15-Crown-5-3D-balls.png
Names
Preferred IUPAC name
1,4,7,10,13-Pentaoxacyclopentadecane [1]
Identifiers
3D model (JSmol)
1618144
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.046.694 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 251-379-6
3897
MeSH 15-Crown-5
PubChem CID
RTECS number
  • SB0200000
  • InChI=1S/C10H20O5/c1-2-12-5-6-14-9-10-15-8-7-13-4-3-11-1/h1-10H2 Yes check.svgY
    Key: VFTFKUDGYRBSAL-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C10H20O5/c1-2-12-5-6-14-9-10-15-8-7-13-4-3-11-1/h1-10H2
    Key: VFTFKUDGYRBSAL-UHFFFAOYAH
  • C1COCCOCCOCCOCCO1
Properties
C10H20O5
Molar mass 220.265 g·mol−1
AppearanceClear, colorless liquid
Density 1.113 g cm−3 (at 20 °C)
Boiling point 93–96 °C (199–205 °F; 366–369 K) at 0.05 mmHg
log P −0.639
1.465
Thermochemistry
−881.1 to −877.1 kJ mol−1
−5.9157 to −5.9129 MJ mol−1
Hazards
GHS labelling:
GHS-pictogram-exclam.svg
Warning
H302, H315, H319
P305+P351+P338
NFPA 704 (fire diamond)
NFPA 704.svgHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
1
0
Flash point 113 °C (235 °F; 386 K)
Safety data sheet (SDS) msds.chem.ox.ac.uk
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

15-Crown-5 is a crown ether with the formula (C2H4O)5. It is a cyclic pentamer of ethylene oxide that forms complex with various cations, including sodium (Na+) [2] and potassium (K+); [3] however, it is complementary to Na+ and thus has a higher selectivity for Na+ ions.

Contents

Synthesis

15-Crown-5 can be synthesized using a modified Williamson ether synthesis: [4]

(CH2OCH2CH2Cl)2 + O(CH2CH2OH)2 + 2 NaOH → (CH2CH2O)5 + 2 NaCl + 2 H2O

It also forms from the cyclic oligomerization of ethylene oxide in the presence of gaseous boron trifluoride. [5]

Properties

Analogous to 18-crown-6, 15-crown-5 binds to sodium ions. Thus, when treated with this complexing agent, sodium salts often become soluble in organic solvents.

First-row transition metal dications fit snugly inside the cavity of 15-crown-5. They are too small to be included in 18-crown-6. The binding of transition metal cations results in multiple hydrogen-bonded interactions from both equatorial and axial aqua ligands, such that highly crystalline solid-state supramolecular polymers can be isolated. Metal salts isolated in this form include Co(ClO4)2, Ni(ClO4)2, Cu(ClO4)2, and Zn(ClO4)2. Seven coordinate species are most common for transition metal complexes of 15-crown-5, with the crown ether occupying the equatorial plane, along with 2 axial aqua ligands. [6]

The structure of the complex [Co(15-crown-5)(H2O)2]. Cobalt complex with 15-crown-5.png
The structure of the complex [Co(15-crown-5)(H2O)2].

15-crown-5 has also been used to isolate salts of oxonium ions. For example, from a solution of tetrachloroauric acid, the oxonium ion [H7O3]+ has been isolated as the salt [(H7O3)(15-crown-5)2][AuCl4]. Neutron diffraction studies revealed a sandwich structure, which shows a chain of water with remarkably long O-H bond (1.12 Å) in the acidic proton, but with a very short OH•••O distance (1.32 Å). [6]

Structure of [(H7O3)(15-crown-5)2] ion ((H7O3)(15-crown-5))+.jpg
Structure of [(H7O3)(15-crown-5)2] ion

A derivative of 15-crown-5, benzo-15-crown-5, has been used to produce anionic complexes of carbido ligands as their [K(benzo-15-crown-5)2]+ salts: [6]

(Ar2N)3MoCH + KCH2Ph + 2 (15-crown-5) → [K(15-crown-5)2]+[(Ar2N)3MoC]− + CH3Ph

See also

References

  1. ↑ "15-crown-5 - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification and Related Records. Retrieved 11 October 2011.
  2. ↑ Takeda, Y.; et al. (1988). "A Conductance Study of 1:1 Complexes of 15-Crown-5, 16-Crown-5, and Benzo-15-crown-5 with Alkali Metal Ions in Nonaqueous Solvents". Bulletin of the Chemical Society of Japan. 61 (3): 627–632. doi: 10.1246/bcsj.61.627 .
  3. ↑ Chen, Chun-Yen; et al. (2006). "Potassium ion recognition by 15-crown-5 functionalized CdSe/ZnS quantum dots in H2O" . Chem. Comm. (3): 263–265. doi:10.1039/B512677K. PMID   16391728.
  4. ↑ Cook, Fred L.; Caruso, Thomas C.; Byrne, Michael P.; Bowers, Chauncey W.; Speck, Don H.; Liotta, Charles L. (1974). "Facile syntheses of 12-crown-4 and 15-crown-5". Tetrahedron Letters. 15 (46): 4029–4032. doi:10.1016/S0040-4039(01)92075-1.
  5. ↑ Liotta, Charles L.; Berkner, Joachim (2001), "15-Crown-5", Encyclopedia of Reagents for Organic Synthesis, Chichester, UK: John Wiley & Sons, Ltd, doi:10.1002/047084289x.rc263, ISBN   978-0-471-93623-7
  6. 1 2 3 Jonathan W. Steed; Jerry L. Atwood (2009). Supramolecular Chemistry, 2nd edition. Wiley. ISBN   978-0-470-51233-3.

Further reading

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