75507-16-3Relevant articles and documents
Crown Cation Complex Effects. 20. Syntheses and Cation Binding Properties of Carbon-Pivot Lariat Ethers
Dishong, Dennis M.,Diamond, Craig J.,Cinoman, Michael I.,Gokel, Geoge W.
, p. 586 - 593 (2007/10/02)
In an effort devise synthetic cation binders that will mimic the behavior of naturally occuring ionophores such as valinomycin, we have prepared approximately 30 macrocyclic (crown) polyethers bearing flexible side chains attached to the macro ring at carbon.In many of these "carbon-pivot" compounds, the side chain contains one or more neutral donor groups that, if in a suitable geometrical arrangement, may provide additional solvation to the macro-ring-bound cation.Although such donors often enhanced the cation binding ability, overall, the increases in stability constants were modest.The physical resemblance and concept of "roping and tying" the cation suggest the name "lariat ethers".Syntheses of these molecules and binding by them of Na+ and K+ cations are reported and conclusions drawn about the structural requirements and cation binding efficacy of these materials.
Synthesis of Substituted Crown Ethers from Oligoethylene Glycols
Ikeda, Isao,Yamamura, Shingo,Nakatsuji, Yohji,Okahara, Mitsuo
, p. 5355 - 5358 (2007/10/02)
A convenient synthetic method for preparing 12-crown-4, 15-crown-5, 18-crown-6, and 21-crown-7 bearing various substituents by intramolecular cyclization of the corresponding substituted oligoethylene glycols in high yields is described.Substituents include modifiable pendent groups such as phenyl and hydroxymethyl, as well as various alkyl groups.Stability constants for the new substituted crown ethers with sodium and potassium ions in methanol were determined by potentiometric titration.The absolute effect of pendent groups on stability constants was insignificant.
