Alkali Metal Ion Binding Research Articles

The Interaction of a Neutral Polymer with Small Ions in Solution. II. The Binding of Alkali Metal Ions to Poly(oxyethylene) in Several Organic Solvents

Abstract The conductivities for several solutions of alkali metal salts, such as potassium thiocyanate, containing poly(oxyethylene) (POE) have been measured as functions of the POE concentration, Cp. A decrease in the conductivity with an increase in Cp has been observed, particularly in methanol, acetonitrile, propylene carbonate, and sulfolane. For these systems, the binding of the cation has been evaluated from the decrease in conductivity and analyzed by a method based on the one-dimensional lattice model. As well as the solvent effects, the effects of the salt concentration and the effect of the alteration of salt on the binding constant have been discussed.

Binding of alkali metal ions by cyclic polyethers: significance in ion transport processes.

Values for the formation constant (log K), the change in enthalpy (triangle upH degrees ), and the change in entropy (triangle upS degrees ) have been determined for the interaction of lithium, sodium, potassium, rubidium, and cesium ions with the two isomers of the cyclic polyether, 2,5,8,15,18,21-hexaoxatricyclo[20.4.0.0(9,14)] hexacosane. The stability order of these metal ions with either isomer is identical to the permeability order for these same metal ions with the structurally related antibiotics, valinomycin and monactin.

Binding of alkali metal ions to polynucleotides

Binding of alkali metal ions to polynucleotides

Electrophoresis of DNA. II. Specific interactions of univalent and divalent cations with DNA

AbstractThe effect of small quantities of metal ions on the electrophoretic mobility of calf thymus DNA in solutions maintained at 0.2 ionic strength with weakly interacting (CH3)4N+ ions yields information about interactions occurring in a region very close to the polymer chain. By means of this technique, it is demonstrated that the binding order to DNA is Li+ > Na+ > K+ for the alkali metal ions and Mn++ > Mg ++ > Ca++ for the divalent ions studied. The quantitative details are compared to earlier work on the long‐chain polyphosphates. Close agreement between the two systems is obtained indicating that an intrinsic property of individual phosphate groups is being observed and that minor discrepancies probably arise from secondary factors. Three types of stability constants representing the binding of alkali metal ions to DNA are calculated and although differing in absolute magnitude, they all satisfactorily represent the result that the order of interaction is Li+ > Na+ > K+ with respective relative strengths of 1.5 : 1 : 0.8.