New pocket ionophores with potential for simulataneous chelation of anions and cations. Synthesis and scope of chelating properties

Arafa, E. A.; Kinnear, K. I.; Lockhart, J. C.

doi:10.1039/c39920000061

Cited by 26 publications

(10 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…42). 87 Detailed 35 Cl NMR and 39 K NMR spectroscopic analyses provided support for the notion that receptor 78 forms a complex with the KCl, wherein the central tetraammonium linker wraps around the Cl − anion so as to bring the two benzo[5]crown-15 ether ring into closer proximity. This wrapping allows the K + cation to be bound in a “sandwich-like” fashion.…”

Section: Ion Pair Receptors Based On Positively Charged Componentsmentioning

confidence: 92%

Ion pair receptors

2010

View full text Add to dashboard Cite

Compared with simple ion receptors, which are able to bind either a cation or an anion, ion pair receptors bearing both a cation and an anion recognition site offer the promise of binding ion pairs or pairs of ions strongly as the result of direct or indirect cooperative interactions between co-bound ions. This critical review focuses on the recent progress in the design of ion pair receptors and summarizes the various binding modes that have been used to accommodate ion pairs (110 references).

show abstract

Section: Ion Pair Receptors Based On Positively Charged Componentsmentioning

confidence: 92%

Ion pair receptors

2010

View full text Add to dashboard Cite

show abstract

“…This should lead to an increase in the available anion concentration and, as a result, higher affinities for the host-guest recognition process. However, inspection of the reported data (see Tables below) proved inconsistent with this assumption; therefore, we were left with an explanation involving a stepwise association process that could involve random order host/anion/cation ion-pairing or potentially sequential allosteric [20,[26][27][28] cation-[anion-host] interactions. In an effort to differentiate between these possible scenarios and to analyze the ion-pair receptor ability of calix[4]pyrrole in more detail, we have carried out a systematic study of the energetics of chloride anion binding by calix [4]pyrrole in the presence of various countercations in halogenated solvents using ITC and have complemented these analyses with computational results (molecular dynamics in explicit solvent) and solid-state X-ray structural data.…”

Section: Introductionmentioning

confidence: 94%

Cooperative Binding of Calix[4]pyrrole–Anion Complexes and Alkylammonium Cations in Halogenated Solvents

Gross

Schmidtchen

Antonius

et al. 2008

Chemistry A European J

View full text Add to dashboard Cite

Calix[4]pyrrole–chloride interactions are affected not only by the choice of countercation in halogenated solvents, but show a specific dependence on the way in which these cations are bound within the electron rich, bowl‐like calix[4]pyrrole cavity formed upon chloride anion complexation. In dichloromethane, the affinities of simple meso‐octamethylcalix[4]pyrrole (1) for methyl‐, ethyl‐, and n‐butylammonium chlorides are on the order of 105, 104, and 102 M−1, respectively, as determined from isothermal titration calorimetry (ITC) analyses. These cation‐dependent anion affinity effects, while clearly evident, are less pronounced in other halogenated solvents, such as 1,2‐dichloroethane. Support for the proposed cation complexation selectivity is provided by solid state X‐ray crystallographic analyses.

show abstract

“…91. 2 Acid 2. To a solution of the formyl crown3 l a (1.55 g, 5.20 x lop3 mol) in acetone at 40 "C was added dropwise with stirring over 0.5 h a freshly prepared solution of potassium permanganate (1.43 g, 9.06 x mol) in acetone-water (10 cm3: 20 cm3).…”

Section: \ M' M'mentioning

confidence: 99%

Design and synthesis of ionophores with multiple receptor sites: solution nuclear magnetic resonance studies of their interaction with chloride, sodium and potassium ions

Kinnear¹,

Mousley²,

Arafa³

et al. 1994

J. Chem. Soc., Dalton Trans.

Self Cite

View full text Add to dashboard Cite

lonophores of the bis(crown ether) type, with polyamine linkers, examples of which are known to bind simultaneously to a cation and its counter anion, have been prepared. One-pot reductive amination, used to couple a benzo-crown aldehyde with aliphatic (both linear and cyclic) and aromatic polyamines, proved to be the most efficient route. A strong inhibition of one synthetic route (amine benzylation) was observed.The competitive interaction between chloride and other anions for binding with the protonated ionophores was examined using 35CI N M R spectroscopy. Sandwich complexing of potassium contrasting with single-face complexation of sodium was demonstrated by 13C N MR spectroscopy.Biological systems frequently organise a molecule with two distinct subunits by a strong ionic or co-ordinative type interaction with a metal ion, which holds the units in position for some other biological strategy. For example the two halves of the iron protein of the nitrogenase complex are organised by an Fe,S, cluster linked to cysteines coming from each half, forming a receptor site into which fits the ATP/ADP unit involved in energy transfer for the hydrogenation of dinitrogen. Such examples have prompted chemical mimicry. In this work a promising bis(crown ether) structure was designed to co-ordinate anions within a cavity produced by organisation of the two ends of the molecule with a strong interaction. In the examples tried ' this 'organisation' is a sandwiching of an alkalimetal cation between two crown ethers. Molecules containing two crown ether moieties, separated by a linking group, are known to sandwich potassium but crystallographic evidence of the structure has been sparse. A recent crystal structure determination of a rubidium complex of a Schiffbase-linked bis(crown ether) shows a double sandwich structure, not previously demonstrated.' This has a potential binding site between the two aromatic fragments which link the two crowns of each individual bis(crown ether), which may be represented as shown in Scheme 1, which we have used previously to describe our designThe 1 : 1 sandwich structure (see Scheme 1) has also been demonstrated crystallographically.6 This paper gives details of synthetic routes to, and the separation and characterisation of, multireceptors which should exhibit multiple binding as outlined by us previously in a preliminary report.' 1980,47,81.

show abstract

New pocket ionophores with potential for simulataneous chelation of anions and cations. Synthesis and scope of chelating properties

Cited by 26 publications

References 6 publications

Ion pair receptors

Ion pair receptors

Cooperative Binding of Calix[4]pyrrole–Anion Complexes and Alkylammonium Cations in Halogenated Solvents

Design and synthesis of ionophores with multiple receptor sites: solution nuclear magnetic resonance studies of their interaction with chloride, sodium and potassium ions

Contact Info

Product

Resources

About