15-Crown-5

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15-Crown-5
Skeletal formula
Ball-and-stick model
Names
Systematic IUPAC name
1,4,7,10,13-Pentaoxacyclopentadecane[1]
Identifiers
33100-27-5 YesY
1618144
ChEBI CHEBI:32401 YesY
ChEMBL ChEMBL156289 YesY
ChemSpider 33416 YesY
EC number 251-379-6
3897
Jmol-3D images Image
MeSH 15-Crown-5
PubChem 36336
RTECS number SB0200000
Properties
C10H20O5
Molar mass 220.27 g·mol−1
Appearance Clear, colorless liquid
Density 1.113 g cm−3 (at 20 °C)
Boiling point 93–96 °C (199–205 °F; 366–369 K) at standard conditions
log P -0.639
1.465
Thermochemistry
-881.1--877.1 kJ mol−1
-5.9157--5.9129 MJ mol−1
Hazards
Safety data sheet msds.chem.ox.ac.uk
GHS pictograms The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word WARNING
H302, H315, H319
P305+351+338
EU classification Harmful Xn
R-phrases R22, R36/38
S-phrases S26
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 113 °C (235 °F; 386 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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.

Properties[edit]

Analogous to 18-crown-6, 15-crown-5 bind 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 includes Co(ClO4)2, Ni(ClO4)2, Cu(ClO4)2, and Zn(ClO4)2. Seven coordinate species are most common for transition metal ions complexes of 15-crown-5, with the crown ether occupying the equatorial plane, along with 2 axial aqua ligands.[4]

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

15-crown-5 have also been used to isolate salts of oxonium ions. For example, from a solution of tetrachloroauric acid, the oxonium ion [H7O3]+ have 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).[4]

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

A derivative of 15-crown-5, benzo-15-crown-5, have been used to produce anionic complexes of carbido ligands as their [K(benzo-15-crown-5)2]+ salts:[4]

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

See also[edit]

References[edit]

  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. 
  4. ^ a b c Jonathan W. Steed; Jerry L. Atwood (2009). Supramolecular Chemistry, 2nd edition. Wiley. ISBN 978-0-470-51233-3. 

Further reading[edit]

External links[edit]