Polyether Complexes Research Articles

A competitive NMR technique for measurements of metal ion-macrocyclic polyether complexation constants in solutions

On developpe une methode RMN pour la determination des constantes de formation des complexes, qui utilise la competition de 2 cations metalliques pour un coordinat donne

An investigation of the kinetic and thermodynamic stability of a tribenzomacrobicyclic polyether complex with Diquat in acetone solution

Variable-temperature 1H n.m.r. spectroscopic studies in CD3COCD3 and u.v. spectroscopic measurements in Me2CO demonstrate that in the 1 : 1 complex, [Diquat·(1)]2+, the quest is encapsulated within the host and that the complexation strength (ΔG°=–7.4 Kcal mol–1) is enhanced by the macrobicyclic cryptate effect.

An electroactive polymer film on a mercury electrode based on a thallium macrocyclic polyether complex

An electroactive polymer film on a mercury electrode based on a thallium macrocyclic polyether complex

Facilitated transport from ternary cation mixtures through water—chloroform—water membrane systems containing macrocyclic ligands

Cation fluxes were determined for various three-component, equimolar mixtures of alkali metal, alkaline earth, and Pb 2+ cations in a H 2OCHCl 3H 2O liquid membrane system incorporating macrocyclic polyethers as carriers. Carrier ligands studied were 18-crown-6, dicyclohexano-18-crown-6, 1,10-diaza-18-crown-6, 21-crown-7, dibenzo-24-crown-8, and cryptand [2.2.2]. Correlations were found between transport and relative cation:polyether cavity radii, the type of substituents present on the polyether ring, and the type and number of donor atoms present. All the ligands studied transported Pb 2+ at higher rates than the other M n+ in the mixtures. Transport behavior in these multi-cation systems can be predicted from M n+ —polyether complex stability constant data in most cases.

ChemInform Abstract: CHEMISTRY OF CROWN ETHERS. XIX. FUNCTIONALIZED CROWN ETHERS FOR THE SOLUBILIZATION OF BARIUM SULFATE

AbstractDurch Reaktion des Diamins (I) mit dem Diester (II) und nachfolgende Reduktion erhält man den Kronenether (IIIa).

Structural studies on molecular complexes of polyethers, 1. Urea‐ethylene oxide oligomer complexes

AbstractComplexes of urea with ethylene oxide oligomeric mixtures were investigated by X‐ray diffraction, IR‐absorption, and differential scanning calorimetry. A new crystal modification (Form II) was found for the complexes of urea with ethylene oxide oligomers whose number average molecular weights ranged from 400 to 1000. The Form II complex has a tetragonal unit cell (a = 7,30 Å, c = 19,51 Å), containing eight molecules of urea and eight ethylene oxide units. This modification is metastable. A solid‐solid transition to the conventional Form I crystal occurs on heating up to a temperature between the melting points of both forms. The dependence of the melting points of these complexes on the molecular weight of the oligomers was also studied.

A “Mechanistic” Macrocyclic Effect in the Gas Phase Chemistry of Metal Ions with Polyethers

Abstract The stability of metal ion - polyether complexes for cyclic polyethers is greater than their linear analogs. This effect has been referred to as the macrocyclic effect. Here, we report a “mechanistic” macrocyclic effect observed in low pressure gas phase ion-molecule reactions involving transition metal ions and both linear and crown ethers. The crown ethers are much more reactive with Cr+ and Fe+ than their linear analog. Presumably, the cyclic ligand forces more parts of the molecule to interact with the metal ion, while only one part of the linear polyethers reacts with these metal centers.

Chemistry of crown ethers XIX. Functionalized crown ethers for the solubilization of barium sulfate

AbstractThe use of seawater as injection fluid in oil‐producing formations often leads to blocking of the wells as a result of barium sulfate‐scale formation. Macrocyclic complexants specifically designed to solubilize barium sulfate efficiently into water have been synthesized and their BaSO4‐solubilizing capacities have been determined. The stability of barium complexes of macrocyclic polyethers can be greatly increased by the introduction of flexible side‐chains containing anionic groups. Most of the newly synthesized complexants, based mainly on diaza‐18‐crown‐6, give very stable complexes. However, many of them are extremely insoluble in water. Only bis(carboxymethyl)diaza‐18‐crown‐6, bis(phosphonomethyl)diaza‐18‐crown‐6 and, to a lesser extent, bis‐(dicarboxymethyl)diaza‐18‐crown‐6 and bis[(hydroxyphosphinyl)methyl]diaza‐18‐crown‐6 are efficient solubilizers of BaSO4 in water.

ChemInform Abstract: SYNTHESIS OF FLUORONAPHTHOQUINONES: HALIDE DISPLACEMENT BY NAKED FLUORIDE

AbstractDurch Komplexierung von KF mit 18‐Krone‐6 wird der Einsatz von nichtsolvatisiertem Fluorid möglich.

Conformation and Ion‐Transport Models for the Structure and Ionic Conductivity in Complexes of Polyethers with Alkali Metal Salts

Two ion‐transport mechanisms are described for ion transport in polyether‐alkali metal salt complexes: an intrahelical jumping process along crystalline (helical) regions of the polymer, and a transport process in the amorphous regions which is dependent on formation of fourfold coordination sites via mutual motion of ether oxygens from two or more polymer chains. The intrahelical jumping process may exhibit Arrhenius behavior, while transport in the amorphous regions should behave like a configurational entropy dominated process, showing a temperature dependence like , where is the equilibrium glass transition temperature. For the highly crystalline poly(ethylene oxide) · complexes, an Arrhenius behavior is observed to dominate, whereas for the amorphous polyether · salt complexes the configurational entropy behavior is observed. Even for the highly crystalline complexes, however, amorphous regions separate the crystalline regions of the polymer, and segmental motion of the polymer chains is postulated to be crucial here as well. The models are consistent with the observed frequency‐dependent ionic conductivity, as well as spectroscopic, x‐ray, thermal, and physical characterization measurements. They provide a reasonable microscopic picture for ion motion and yield testable predictions concerning the dependence of the ionic conductivity on pressure, temperature, and crystallinity.

The oxonium (H3O+) cation: molecular structure of an oxonium-macrocyclic polyether complex

The oxonium (H3O+) cation: molecular structure of an oxonium-macrocyclic polyether complex

Field desorption and chemical ionization mass spectra of ‘crown’ and macrobicyclic polyether complexes of potassium

The potassium complexes of five crown ethers have been investigated by field desorption and by chemical ionization desorption mass spectrometry with ammonia as the carrier. Three have also been investigated by the latter technique with methane as the carrier. For two macrobicyclic crown ethers simple F.D. spectra corresponding to [L + K] + were obtained; benzo-15-crown-5 showed the [L 2 + K] + sandwich and dibenzo-2-crown-8 gave an ion corresponding to [L + K] +, the ligand 18-crown-6 appeared to volatilise without ionizing and yielded spectra in F.D. corresponding to potassium thiocyanate. With ammonia all five ligands gave [L + NH 4] + as the most abundant ion, benzo-15-crown-5 also gave some [L 2 + NH 4] +; some fragmentation was obtained. With methane there is more extensive fragmentation although the parent [L + H] + was in fair abundance.

Structure and ion transport in polymer-salt complexes

Polymer electrolytes based on alkali metal complexes of polyethers and cross-linked polyethers have significant cation mobility, which appears to arise from large-amplitude motions of the polymer. High chain flexibility not only promotes ion transport but it also is important for the initial formation of polymer-salt complexes. Several new polymer electrolyte systems are discussed which contain flexible polymer backbones and high concentrations of polar groups.

Correlation of molecular conformation and thermodynamic stability of metalcation complexes of 1,4,7,10,13-pentaoxa-16-thiacyclooctadecane

The results of crystal-structure analyses of 1,4,7,10,13-pentaoxa16-thiacyclooctadecane (I) and its complexes with NaSCN, KSCN, RbSCN and AgNO3 are discussed. In all four complexes the cation coordinates to the five O atoms of the polyether sulfide (I). The sulfur-cation interaction for the complexes depends on the cation. The sulfur-cation interaction is strong and partially covalent with the Ag ÷ complex, but weak with the K ÷ and Rb ÷ complexes. In these three structures the S atom is directed into the cavity of the ligand. There is no interaction between the S and the cation in the Na ÷ complex. In both the Na÷-complexed and uncomplexed ligand, the S atom is directed away from the cavity of the ligand. The cation-oxygen ion-dipole electrostatic interaction is the main factor in the thermodynamic stability of the alkali-metal complexes, while the Ag ÷ complex is stabilized by both the cation-oxygen and cation-sulfur interactions. Correlations are made between the thermodynamic stabilities of cation complexes of 1,4,7,10,13,16-hexaoxacyclooctadecane, 1,4,7,10,13-pentaoxacyclopentadecane, 1,4,7,10,13,16-hexaoxacyclooctadecane-2,6dione and (I), and molecular conformation determined by X-ray diffraction. These correlations provide a basis for determining the effect various ligand parameters have on the thermodynamic stability of polyether complexes.

The synthesis and complexation of open chain polyethers having various end groups

The syntheses of a series of oxygen containing ligands of general formula o-ROC 6H 4O(CH 2CH 2O) n oC 6H 4OR′ are described; the complex formation of these ligands with alkali and alkaline earth metal cations has been investigated. Stability constants for sodium and potassium increase as n is increased from 1 to 3, as R is varied through the series, H, CH 2C 6H 5, CH 2CH 2OH, CH 2CO 2C 2H 5, CH 2CO 2H. When R and R′ are different, the stability constant is intermediate between that found when both end groups are R and that when both are R′. In these compounds there is no evidence for the presence of internal hydrogen bonding contributing to the stability of the complexes.

The Crystal and Molecular Structure of 2-{8-(2-Aminophenoxy)-3,6-dioxaoctyloxy}benzoic Acid · NaClO4, a Linear Polyether with Terminal Amino and Carboxyl Functions

Abstract The title compound, C19H23NO6 · NaClO4, crystallizes in the monoclinic space group P21/c with cell dimensions a = 16.374(5), b = 9.856(4), c = 27.245(8) Å, β = 91.88(5)° and Z = 8. The structure of this polyether complex was solved on the basis of 4501 diffractometer measured reflections and refined to an Rw of 0.091. There are two molecules per asymmetric unit which are related to each other by an approximate non-crystallographic centre of symmetry. Both complex molecules exist in the favourable zwitterion configuration with ion pair attraction between the amino (NH3 +) and carboxyl(COO -) end groups of the polyether ligand. The Na+ion is circulary coordinated to all except the oxygen atoms of the aminophenoxy end group of the polyether ligand suggesting that this oxygen has reduced electronegativity. All C-C and C-O bonds of the ligand exist in favourable gauche and trans conformations.

Molecular complexes of cyclic polyethers. 6. Structure of and binding interactions in a host-guest complex of a macrocyclic hexaether with tert-butylammonium perchlorate. Survey of crystallographic data

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular complexes of cyclic polyethers. 6. Structure of and binding interactions in a host-guest complex of a macrocyclic hexaether with tert-butylammonium perchlorate. Survey of crystallographic dataIsrael GoldbergCite this: J. Am. Chem. Soc. 1980, 102, 12, 4106–4113Publication Date (Print):June 1, 1980Publication History Published online1 May 2002Published inissue 1 June 1980https://doi.org/10.1021/ja00532a021RIGHTS & PERMISSIONSArticle Views104Altmetric-Citations25LEARN 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 (873 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Intermolecular charge-transfer complexes of macrocyclic polyethers with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIntermolecular charge-transfer complexes of macrocyclic polyethers with 2,3-dichloro-5,6-dicyano-1,4-benzoquinoneR. Malini and V. KrishnanCite this: J. Phys. Chem. 1980, 84, 5, 551–555Publication Date (Print):March 1, 1980Publication History Published online1 May 2002Published inissue 1 March 1980https://doi.org/10.1021/j100442a022RIGHTS & PERMISSIONSArticle Views68Altmetric-Citations17LEARN 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 (566 KB) Get e-Alerts

ChemInform Abstract: THE EFFECT OF MACROCYCLIC POLYETHERS ON THE ALKYLATION OF SODIUM 2‐NAPHTHOLATE

AbstractBei der Alkylierung des Naphtholats (I) mit den Halogeniden (II) bewirkt in H2O, THF oder Benzol der Zusatz der Kronenether (V) oder (VI) ‐ im Vergleich zur Reaktion in deren Abwesenheit ‐ eine signifikante Steigerung der Ausbeuten der O‐Alkylierungs‐ (III) gegenüber den C‐Alkylierungsprodukten (IV); dagegen ist in den Lösungsmitteln DMF oder Acetonitril ein solcher Zusatz ohne jede Wirkung.

The Effect of Macrocyclic Polyethers on the Alkylation of Sodium 2-Naphtholate

Abstract The alkylation of sodium 2-naphtholate, in the presence of benzo-18-crown-6 or 4,7,13,16,21,24-hexaoxabicyclo[8.8.8]hexacosane is found to give high ratios of O/O+C alkylation when conducted in THF, in benzene, and in water. The striking increase in the product ratio is attributed to a specific complexation of the macrocyclic polyethers, which facilitate the dissociation of the ion-pair aggregate of the sodio-derivative which exists in benzene or THF. The polyethers may act as phase-transfer catalysts when the reaction is run in water. In support of this conclusion, the reaction in DMF or acetonitrile, in which the dissociation of sodium 2-naphtholate takes place, fails to show any effect of the macrocyclic polyethers on the product ratio.