Solvent effect on the complex formation of a crown ether derivative with sodium and potassium ions. Thermodynamic background of selectivity

2013 ◽  
Vol 556 ◽  
pp. 94-97 ◽  
Author(s):  
Yin Li ◽  
Péter Huszthy ◽  
Ildikó Móczár ◽  
Balázs Szemenyei ◽  
Sándor Kunsági-Máté
Keyword(s):  
Complex Formation ◽  
Crown Ether ◽  
Solvent Effect ◽  
Potassium Ions ◽  
Ether Derivative ◽  
Thermodynamic Background ◽  
Sodium And Potassium

Coumaryl crown ether based chemosensors: selective detection of saxitoxin in the presence of sodium and potassium ions

2002 ◽  
Vol 43 (25) ◽  
pp. 4413-4416 ◽  
Author(s):  
Péter Kele ◽  
Jhony Orbulescu ◽  
Tiffany L Calhoun ◽  
Robert E Gawley ◽  
Roger M Leblanc
Keyword(s):  
Crown Ether ◽  
Potassium Ions ◽  
Selective Detection ◽  
Sodium And Potassium

ChemInform Abstract: Coumaryl Crown Ether Based Chemosensors: Selective Detection of Saxitoxin in the Presence of Sodium and Potassium Ions.

ChemInform ◽  
2010 ◽  
Vol 33 (36) ◽  
pp. no-no
Author(s):  
Peter Kele ◽  
Jhony Orbulescu ◽  
Tiffany L. Calhoun ◽  
Robert E. Gawley ◽  
Roger M. Leblanc
Keyword(s):  
Crown Ether ◽  
Potassium Ions ◽  
Selective Detection ◽  
Sodium And Potassium

1,2-Bis(azacrown)ethanes: Effect of Bridge Substitution and Ring Size on Formation of Sandwich Complexes with Sodium and Potassium Ions

1993 ◽  
Vol 58 (1) ◽  
pp. 153-158 ◽  
Author(s):  
Martin Bělohradský ◽  
Petr Holý ◽  
Juraj Koudelka ◽  
Jiří Závada
Keyword(s):  
Complex Formation ◽  
Homologous Series ◽  
Potassium Ions ◽  
Ring Size ◽  
Sandwich Complexes ◽  
Sandwich Complex ◽  
Symmetry Violation ◽  
Title Problem ◽  
Sodium And Potassium

The title problem was investigated potentiometrically using four homologous series of bis(azacrown)s I-IV. A surprisingly large destabilizing effect of bridge substituent was found in the intramolecular sandwich complex formation and ascribed to symmetry violation.

A novel crowned porphyrin derived from meso-tetrakis(penta-fluorophenyl)porphyrin

2003 ◽  
Vol 07 (06) ◽  
pp. 399-404 ◽  
Author(s):  
Maria Carolina A. F. Gotardo ◽  
Hérica C. Sacco ◽  
Juvenal C. S. Filho ◽  
Antônio G. Ferreira ◽  
Antônio Claudio Tedesco ◽  
...  
Keyword(s):  
Crown Ether ◽  
Ionic Radius ◽  
Potassium Ions ◽  
Aggregation Process ◽  
Sodium Ions ◽  
Dimerization Constant ◽  
Chloroform Methanol ◽  
Sodium And Potassium ◽  
Spectroscopic Behavior ◽  
Absorption Measurements

The porphyrin 5,10,15,20-tetrakis[4-(1,4,7,10,13-pentaoxacyclopentadecane-2-aminomethyl)2,3,5,6-tetrafluorophenyl]porphyrin,T15C5P, was synthesized by the reaction of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin with the crown ether 2-aminomethyl-(15-crown-5). The crowned porphyrin showed a distinct spectroscopic behavior in the presence of sodium and potassium ions. Dimerization studies based on absorption measurements clearly indicate that T15C5P aggregates in the presence of potassium ions in chloroform/methanol medium (1.0 × 10−5 mol.L −1 or 1.0 × 10−4 mol.L −1), with a dimerization constant ( K D ) of 2.14 × 10−5 and 2.23 × 10−5, respectively. The same formalism applied to the T15C5P in the presence of sodium ions indicated absence of the aggregation process. The ionic radius of Na + is suitable to fit well into the cavity of 15-crown-5 moieties, leading to intramolecular complexes only. Potassium ion is too large to lie in the hole of the crown ether entities and is probably located between two porphyrin molecules, promoting 2:1 aggregated complexes through it's sandwiching, as is observed for phthalocyanines.

Sodium and Potassium Fluxes in the Abdominal Nerve Cord of the Cockroach, Periplaneta Americana L

1961 ◽  
Vol 38 (2) ◽  
pp. 315-322
Author(s):  
J. E. TREHERNE
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nerve Cord ◽  
Periplaneta Americana ◽  
Unit Area ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Nerve Sheath ◽  
The Central Nervous System ◽  
Sodium And Potassium

1. The influx of sodium and potassium ions into the central nervous system of Periplaneta americana has been studied by measuring the increase in radioactivity within the abdominal nerve cord following the injection of 24NA and 42K. into the haemolymph. 2. The calculated influx of sodium ions was approximately 320 mM./l. of nerve cord water/hr. and of potassium ions was 312 mM./l. of nerve cord water/hr. These values are very approximately equivalent to an influx per unit area of nerve cord surface of 13.9 x 10-2 M cm. -2 sec.-1 for sodium and 13.5 x 10-12 M cm. -2 sec.-1 for potassium ions. 3. The relatively rapid influxes of these ions are discussed in relation to the postulated function of the nerve sheath as a diffusion barrier. It is suggested that a dynamic steady state rather than a static impermeability must exist across the sheath surrounding the central nervous system in this insect.

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