Acyclic Polyethers Research Articles

Sodium(1+) complexes with acyclic polyethers. Stabilities, enthalpies, and entropies of reaction in acetonitrile and pyridine. A sodium-23 NMR study

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSodium(1+) complexes with acyclic polyethers. Stabilities, enthalpies, and entropies of reaction in acetonitrile and pyridine. A sodium-23 NMR studyJean Grandjean, Pierre Laszlo, Werner Offermann, and Peter L. RinaldiCite this: J. Am. Chem. Soc. 1981, 103, 6, 1380–1383Publication Date (Print):March 1, 1981Publication History Published online1 May 2002Published inissue 1 March 1981https://doi.org/10.1021/ja00396a015RIGHTS & PERMISSIONSArticle Views83Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (488 KB) Get e-Alerts Get e-Alerts

NMR SPECTROSCOPIC BEHAVIOR OF THE COMPLEXES OF SOME POLYETHYLENE GLYCOL DERIVATIVES WITH ALKALI IONS

Abstract Four triethylene glycol derivatives, which have different end substituents, quinolyl and ortho-substituted phenyl groups, were synthesized in good yields. The proton NMR spectrum of these compounds and their complexes with alkali and ammonium ions was measured to show that these compounds exhibit complexation specificity for sodium ion. On complexation, these acyclic polyethers are considered to wrap adequately themselves around sodium ion like a pseudocyclic species.

Multidentate Acyclic Neutral Ligands and Their Complexation

AbstractThe properties of cyclic crown ethers are approximated by acyclic neutral ligands (popdands), which are compared and contrasted with open‐chain bioionophores and acidic chelating agents in this article. Variations of the endo‐polarophilicity/exo‐lipophilicity balance, complex stability, ion slectivity can often be accomplished more easily, with greater versatility, and at less expense with acyclic polyethers than with their cyclic counterparts; complexation and decomplexation are generally faster in acyclic systems; and the pseudocavity usually has greater conformational flexibility. Acyclic crown ethers and open‐chain cryptands stiffened by rigid “terminal groups” containing donor atoms readily form crystalline complexes of alkali and alkaline earth metals. Some oppen‐chain neutral ligands form helical conformations in their crycstalin complexes. The observed coordination numbers and geometries are of theoretical interst. Attractive terminal group interactions lead to pseudocyclic species occupying a position intermediate between cyclic and acyclic ligands. It has recently proved possible to isolate crystalline complexes of alkali and alkaline earth metal ions with weakly donating oligo(ethylene glycol ethers) and with glycols; such complexes have also been obtained with sugars. Acyclic neutral ligands can serve as simple models of nigericin‐type bioionophores and be used analytically in microelectrodes. The recently discoverd crystalline stoichiometric complexes formed by some acyclic neutral ligands with guest molecules such as urea, thiourea, and water provide a fresh insight into weak interactions between neutral molecules and for the development of urea receptors.