NMR-Studies of the Interaction of Metal Ions with Poly-(1,4-hexuronates). III. Proton Magnetic Resonance Study of the Binding of Lanthanides to Methyl alpha-D-Gulopyranoside in Aqueous Solution.

Grasdalen, Hans; Anthonsen, T.; Larsen, Bjørn; Smidsrød, Olav; Dahl, O.; Buchardt, Ole; Schroll, Gustav

doi:10.3891/acta.chem.scand.29b-0017

Cited by 24 publications

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“…The intensity loss observed in this region for the complexes indicates a weakening of the alcoholic CO stretching vibrations and strongly suggests the participation of alcoholic oxygens in complexation. On the other hand, no change was observed that characterized the ether group at 1157 cm −1 , supporting the previous reports that coordination to the metal is through the O(2) and O(3) atoms not through the etheric oxygen 14, 15. The spectra of the complexes displayed two new peaks at about 1500 and 1387 cm −1 .…”

Section: Resultssupporting

confidence: 85%

Dextran–rare earth ion interactions. II. Solid‐state characteristics

Zümreoǧlu‐Karan

Mazi

Güner

2001

J of Applied Polymer Sci

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ABSTRACT:The solid-state characteristics of dextran complexes precipitated from aqueous solutions with three different light-lanthanoid cations (La 3ϩ , Ce 3ϩ , and Nd 3ϩ ) were investigated by spectroscopic and thermal methods. Spectroscopic characterization was realized by the comparative interpretation of the FTIR spectra, and the complexes were found to involve both ligating water and dextran through its O(2) and O(3) atoms. Remarkable spectral changes were noted, particularly with La 3ϩ , which parallels the previous solution studies. The order of La 3ϩ Ͼ Ce 3ϩ Ͼ Nd 3ϩ was determined to display the tendency of the Ln 3ϩ ion in favor of dextran throughout the competition between water and dextran. The thermal stabilities of the complexes were examined by thermogravimetry (TG), differential TG, and DSC methods. The decomposition steps and temperatures were assigned with respect to the lanthanoid ions used. The TG and DSC results indicated that the complexes are less stable thermally than dextran itself with increasing thermal stabilities in the order of La 3ϩ Ͻ Ce 3ϩ Ͻ Nd 3ϩ in their anhydrous states.

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Section: Resultssupporting

confidence: 85%

Dextran–rare earth ion interactions. II. Solid‐state characteristics

Zümreoǧlu‐Karan

Mazi

Güner

2001

J of Applied Polymer Sci

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“…The discontinuity in the curve has been attributed to a probable conformational transition of the polymer chain, the interaction of the polymer with cosolute,13, 14 and/or complex formation dynamism in the polymer/cation system 15. It is quite plausible that the minima points in Figures 1 and 2 show a transition to the 1:1 complex which is the most favorable stoichiometry for the lanthanide–sugar complexes 16, 17…”

Section: Resultsmentioning

confidence: 99%

Dextran–rare earth ion interactions. I. Dynamics in aqueous solutions

Mazi

Zümreoǧlu‐Karan

Güner

2001

J of Applied Polymer Sci

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ABSTRACT:The interaction of light-lanthanoid cations (La 3ϩ , Ce 3ϩ , and Nd 3ϩ ) with dextran in aqueous solutions was studied by viscosimetric, turbidimetric, and conductimetric methods. The effects of the type of the cation and the concentration of the cation on the interaction mechanism were investigated. Viscosity behavior of the solutions was interpreted using the Huggins and Kraemer equations; intrinsic viscosities and the slopes were calculated. The results found from the Huggins and Kraemer approaches accorded well. The order of interaction was determined as La 3ϩ Ͼ Ce 3ϩ Ͼ Nd 3ϩ . In all experimental methods applied, a critical concentration of the Ln 3ϩ ion (Ϸ0.08 mol Ln 3ϩ /L) was noted at which the observed property showed a significant change. Up to this critical concentration, viscosities of the dextran/Ln 3ϩ solutions decreased and after making an outstanding turn at this point increased toward higher concentrations. Turbidimetric and precipitation experiments gave opposite results as expected but the same order for the cation and the same value of critical concentration. The results obtained from the application of a mathematical model to the precipitation data verified the conclusions attained by viscosimetry and conductimetry.

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