Synthetic Ionophores Research Articles

ChemInform Abstract: Conformation‐Dependent 13C Chemical Shifts: A New Means of Conformational Characterization as Obtained by High‐Resolution Solid‐State 13C NMR

A survey of recent high-resolution solid-state 13C NMR studies is given to illustrate how and to what extent 13C chemical shifts of a variety of molecular systems are displaced upon conformational changes. Examples are taken from studies of alkanes, polysaccharides, polypeptides, and naturally occurring and synthetic ionophores, in which more than single conformations are available owing to either crystalline polymorphs or a variety of metal-ligand interactions. The magnitude of the conformation-dependent 13C chemical shifts are in many instances as large as 8 ppm and are well related to a set of torsion angles of nearby single bonds. The application of this concept to conformational characterization is also discussed.

Organometallic ionophore for alkali metal cations

Complexes of a novel synthetic organometallic ionophore with lithium and sodium cations have been characterized by single-crystal X-ray diffraction. The crystal structure of the lithium complex consists of cation-liganddimers with a tetrahedral coordination around Li. The sodium complex reveals a different structure type consisting of cation-ligandtrimers, with water molecules being included between the trimeric entities. The coordination sphere around the Na ions has a distorted octahedral symmetry. It is anticipated that the observed structures of dinuclear Li and trinuclear Na complexes represent possible modes of aggregation of the cation-ligand entities in lipophilic media.

A High Resolution 23Na NMR Study of Sodium Complexes with Ionophores in Solution. Stability of Complexes as Viewed from Displacements of 23Na Chemical Shifts as Referred to Those in the Solid State

Abstract We have recorded 23Na NMR spectra of sodium complexes with naturally occurring and synthetic ionophores in chloroform and methanol solution, to gain insight into conformational stability of these complexes as examined from the displacements of 23Na chemical shifts with respect to those in the solid state. Interestingly, the 23Na chemical shifts of sodium complexes with monensin and tetranactin obtained in chloroform solution are very close to those in the solid, as a result of adopting similar conformation between the solid and solution. For the rest of complexes, however, the 23Na NMR signals are displaced downfield in solution as compared with those of the solid state. Such downfield shifts are well interpreted in terms of the presence of conformational fluctuation and/or sodium ions interacting with solvent or anions. Therefore, downfield displacement is more significant in methanol which can be good ligand molecules. The presence of fluctuation-induced quadrupole coupling constants is consistent with our view about 23Na chemical shifts. These quadrupole interactions were reduced in methanol solution, owing to the presence of exchange with solvents.

Conformation‐dependent 13C chemical shifts: A new means of conformational characterization as obtained by high‐resolution solid‐state 13C NMR

AbstractA survey of recent high‐resolution solid‐state 13C NMR studies is given to illustrate how and to what extent 13C chemical shifts of a variety of molecular systems are displaced upon conformational changes. Examples are taken from studies of alkanes, polysaccharides, polypeptides, and naturally occurring and synthetic ionophores, in which more than single conformations are available owing to either crystalline polymorphs or a variety of metal‐ligand interactions. The magnitude of the conformation‐dependent 13C chemical shifts are in many instances as large as 8 ppm and are well related to a set of torsion angles of nearby single bonds. The application of this concept to conformational characterization is also discussed.

Pr 3+ transport across phosphatidylcholine vesicles mediated by open crown synthetic ionophores

Pr 3+ transport experiments, varying temperature and concentration, show that open crow in synthetic polyethers (podands) mediate Pr 3+ translocation across phosphatidylcholine vesicles by a carrier mechanism. Enhancement of the proton countertransport induced by addition of a protonophore, increases the cation inward rate.

Binding and transport of alkali metal ions by synthetic analogues of nactins

Our new synthesis of 32-linked macrocycles, models of nactin ionophores, has been extended to more complex structures. The complexation properties of these macrocycles were determined using the method of extraction of alkali metals from an aqueous phase. Extraction constants of some compounds are much higher than those measured for nonactin and for dibenzo-18-crown-6, whereas the association constants measured for the same alkali metals are very weak. There is no complexation selectivity towards the cations, only a slight preference for lithium is observed. These synthetic ionophores are able to transport alkali metal ions through a non-polar barrier, but without clear selectivity. The measured rates are lower than those obtained for nonactin and dibenzo-18-crown-6, the decomplexation being the rate-determining step.

A coiled synthetic carboxylic ionophore capable of encapsulating a potassium ion

A synthetic carboxylic ionophore with eight ether oxygen and five aromatic rings mediated selective K+ ion transport through a liquid membrane; the coiled carboxylate-encapsulated potassium ion is highly lipophilic.

Neutral carrier based silicone rubber membranes for H3O+, K+, NH4 + and Ca2+ selective electrodes

Silicone rubber is a universal membrane matrix for neutral carrier based ion-selective electrodes. Carrier antibiotics as well as synthetic ionophores yield sensors with selectivities that are comparable or even higher than those of corresponding poly(vinyl chloride) (PVC) membrane systems. The permeability of silicone rubber membranes for gas molecules is about ten times higher than the permeability of PVC membranes. In contrast, the electrical conductivity is by a factor of 10–100 lower.

ChemInform Abstract: COMPLEXATION OF CALCIUM BY THE SYNTHETIC IONOPHORE MCN‐4308, (2‐(4‐(DIPHENYLMETHY)‐1‐PIPERIDINYL)‐2‐OXOETHOXY)ACETIC ACID. CRYSTAL AND MOLECULAR STRUCTURE OF THE FREE ACID AND OF THE CALCIUM COMPLEX

Chemischer InformationsdienstVolume 14, Issue 3 Physical Organic Chemistry ChemInform Abstract: COMPLEXATION OF CALCIUM BY THE SYNTHETIC IONOPHORE MCN-4308, (2-(4-(DIPHENYLMETHY)-1-PIPERIDINYL)-2-OXOETHOXY)ACETIC ACID. CRYSTAL AND MOLECULAR STRUCTURE OF THE FREE ACID AND OF THE CALCIUM COMPLEX P. VAN ROEY, P. VAN ROEYSearch for more papers by this authorG. D. SMITH, G. D. SMITHSearch for more papers by this authorW. L. DUAX, W. L. DUAXSearch for more papers by this authorM. J. UMEN, M. J. UMENSearch for more papers by this authorB. E. MARYANOFF, B. E. MARYANOFFSearch for more papers by this author P. VAN ROEY, P. VAN ROEYSearch for more papers by this authorG. D. SMITH, G. D. SMITHSearch for more papers by this authorW. L. DUAX, W. L. DUAXSearch for more papers by this authorM. J. UMEN, M. J. UMENSearch for more papers by this authorB. E. MARYANOFF, B. E. MARYANOFFSearch for more papers by this author First published: January 18, 1983 https://doi.org/10.1002/chin.198303091Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume14, Issue3January 18, 1983 RelatedInformation

Active transport of alkali metal cations: a new type of synthetic ionophore derived from a crown ether

A new type of synthetic ionophore having both an 18-crown-6 ring and a primary amino group in the same molecule displayed and excellent K+/Na+ selective and active transport across a liquid membrane based on the reversible intramolecular complexation of the crown ring and the ammonium ion.

Solvation properties of natural and synthetic ionophores. I. Stoichiometry of complexes with alkali and alkaline earth cations in aprotic organic solvents

Ion-solvent interactions play a very important role in the studies of stoichiometry, structure, and stability of complexes of cations with natural and synthetic ionophores. These compounds are extremely useful in study of the interaction of neutral salts with macromolecules and the mechanism of cation transport across biological membranes. Knowledge of the ionophore solvation properties enables one to choose a suitable solvent for complexation studies and to obtain detailed information on the solvent effect. We would like to present in this paper a very simple method of estimating the solvation properties of ionophores. We treat the ligand as an assembly of individual noninteracting binding sites. The solvation properties of solvents can be used to represent the solvation sites in natural and synthetic ligands. The solvation properties are represented by the Gutmann donor number (DN) of the model solvent. We can define the solvation ability of a ligand binding site be "donor number of binding site" (DN binding site), which in turn can be represented by the DN of the appropriate model solvent. The average DN of the ligand (DN average) is defined as [xi ni-1 (DN binding site)i]/n, where n is the number of the ligand binding sites. Comparison of the DN average with the DN solvent, together with the knowledge of the composition of the system, characterizes remarkably well the solvation properties of the ligand. This model explains (a) the stoichiometry of many alkali and alkaline earth cation complexes with natural and synthetic ligands in aprotic organic solvents, (b) the transport of alkali and alkaline earth cations across lipid bilayers, and (c) how polypeptides and proteins interact with neutral salts in solutions.

Complexation of calcium by the synthetic ionophore McN-4308, [2-(4-(diphenylmethy)-1-piperidinyl)-2-oxoethoxy]acetic acid. Crystal and molecular structure of the free acid and of the calcium complex

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComplexation of calcium by the synthetic ionophore McN-4308, [2-(4-(diphenylmethy)-1-piperidinyl)-2-oxoethoxy]acetic acid. Crystal and molecular structure of the free acid and of the calcium complexPatrick Van Roey, G. David Smith, William L. Duax, Michael J. Umen, and Bruce E. MaryanoffCite this: J. Am. Chem. Soc. 1982, 104, 21, 5661–5666Publication Date (Print):October 1, 1982Publication History Published online1 May 2002Published inissue 1 October 1982https://doi.org/10.1021/ja00385a018RIGHTS & PERMISSIONSArticle Views47Altmetric-Citations4LEARN 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 (1 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Selective Transport of Potassium Ions against Their Concentration Gradient by Pentaethylene Glycol Derivative Containing Both 8-Quinolyl and o-Carboxylphenyl Terminal Groups

Abstract A pentaethylene glycol derivative containing both 8-quinolyl and o-carboxylphenyl terminal groups can transport potassium ions selectively against the concentration gradient in liquid membrane systems containing more than one alkali ion species in aqueous solution. Uptake of cations by this synthetic ionophore from the aqueous solution into the organic layer is confirmed to be important for exhibiting this excellent selectivity toward potassium ions.

Structural chemistry of natural and synthetic ionophores and their complexes with cations.

Although the antibiotics nigericin and lasalocid as first representatives of the naturally occurring ionophores were isolated as early as 1951 from Streptomyces cultures 1), it was only in the late sixties that the function of these membranes affecting compounds as complexing and transporting agents for alkali metal ions was established 2–4). Once their outstanding properties as selective alkali cation carriers had been understood, however, they attracted the attention of numerous investigators, and many details have been learnt about their structures, complex formation and physiological activity. Furthermore, a considerable number of model compounds were synthesized, above all the so-called polyether ligands which did not only help to understand the mechanism of action of the naturally occurring ionophores but also led to the rapid development of phase-transfer techniques in organic chemistry, to mention only one application.

31P NMR spectroscopic study of Pr 3+ transport by etheromycin and by synthetic ionophores

Summary The transport of Pr 3+ across phosphatidylcholine vesicles by etheromycin ( 1 ) is first-order in Pr 3+ and second-order in 1 . It has an Arrhenius activation energy E a = 120 kJ.mol −1 , consonant with carrier-mediated transport. The Pr 3+ cations are transported inside complexed with two molecules of the conjugate base of 1 . The ionophore returns to the outside of the membrane as 1 − , H + . Such an antiport mechanism is structurally unavailable to ligands 2–5. Only in the presence of an uncoupler such as picrate does transport occur at a useful rate with such synthetic ligands.

A synthetic ionophore for Ca2+: studies with model and biological systems.

We show that the relatively simple beta-diketone, 1.1.1.2.2.3.3-heptafluoro-7,7-dimethyloctane-4,6-dione, known as "fod", will solvate Ca2+ ions in an organic phase. In consequence it will transport Ca2+ across phospholipid bilayers. It acts as predicted for a Ca2+-transporting ionophore in two biological systems: it will stimulate Ca2+-dependent K+ efflux from human red blood cells, and Ca2+-dependent histamine secretion from rat peritoneal mast cells.

NEW, NONCYCLIC IONOPHORES EXHIBITING SELECTIVE CATION TRANSPORT AGAINST THE CONCENTRATION GRADIENT

Abstract Some oligoethylene glycol derivatives containing both quinolyl and carboxyl terminal groups were prepared as synthetic ionophores. These polyethers can transport alkali ions selectively through liquid membrane against the concentration gradient. The rate of the active transport and the ion-selectivity with them change with changing the length of oxyethylene chain.

The effect of benzo‐18‐crown‐6, a synthetic ionophore, on stomatal opening and its interaction with abscisic acid

Abstract. Treatment of tomato seedlings with 5 mM benzo‐18‐crown‐6, a potassium ionophore, produced a reduction in transpiration of 40%. Treatments of epidermal strips of Commelina communis with ben‐zo‐18‐crown‐6 (1‐l0mM) inhibited stomatal opening, and this effect was shown to be reversible. An antagonistic interaction between abscisic acid (10−7M) and benzo‐18‐crown‐6 (4 × 10−3 M) was also observed.

Functions of Acyclic Poly(ethylene Oxide) Homologs: Acceleration of Nucleophilic Reactions and Selective Ion Transport through Membranes

Abstract The acceleration effect of poly(ethylene oxide) on nucleophilic reactions was investigated. The enhancement of the reaction rate was interpreted by the cooperative solvation of alkali metal ions with ethereal oxygens of PEO resulting in active nucleophilic anions. In relation to the complex formation of alkali metal ions with PEO, the oligo(ethylene oxide) derivatives were prepared as the synthetic ionophores, which were able to transport alkali metal ions selectively through a liquid membrane against the alkali metal ion concentration.

ChemInform Abstract: SELECTIVE ALKALI METAL ION TRANSPORT WITH SYNTHETIC IONOPHORES

Chemischer InformationsdienstVolume 9, Issue 43 Isocyclic Compounds ChemInform Abstract: SELECTIVE ALKALI METAL ION TRANSPORT WITH SYNTHETIC IONOPHORES N. YAMAZAKI, N. YAMAZAKISearch for more papers by this authorS. NAKAHAMA, S. NAKAHAMASearch for more papers by this authorA. HIRAO, A. HIRAOSearch for more papers by this authorS. NEGI, S. NEGISearch for more papers by this author N. YAMAZAKI, N. YAMAZAKISearch for more papers by this authorS. NAKAHAMA, S. NAKAHAMASearch for more papers by this authorA. HIRAO, A. HIRAOSearch for more papers by this authorS. NEGI, S. NEGISearch for more papers by this author First published: October 24, 1978 https://doi.org/10.1002/chin.197843166Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume9, Issue43October 24, 1978 RelatedInformation