63 research outputs found
Complex formation and lactonization reactions in aqueous solutions containing Ca2+ or Nd3+ ions and sugar-type ligands
Dielectric response of light, heavy and heavy-oxygen water: isotope effects on the hydrogen-bonding network's collective relaxation dynamics
Ion-pairing equilibria and kinetics of dimethyl phosphate: A model for counter-ion binding to the phosphate backbone of nucleic acids
Dissolution of calcium(II) dodecyl sulphate precipitates in the presence of alcohols : [abstract]
Dielectric Response of Light, Heavy and Heavy-Oxygen water: Isotope Effects on the Hydrogen-Bonding Network's Collective Relaxation Dynamics
Ion-pairing equilibria and kinetics of dimethyl phosphate: A model for counter-ion binding to the phosphate backbone of nucleic acids
Dimethyl phosphate (DMP–) is the simplest model ion to assess ion-pairing phenomena between metal ions and the phosphate backbone of nucleic acids. Yet, the equilibria and dynamics of ion binding to DMP– have not been fully uncovered. Here, we study the interaction of DMP– with different cations and water in aqueous solutions of NaDMP using dielectric relaxation and nuclear magnetic resonance spectroscopies. We find DMP– to be weakly hydrated and weakly associated with Na+ in the absence of added salt. Upon addition of NaCl, MgCl2, or CaCl2 to solutions of NaDMP, we detect the formation of solvent-shared (NaDMP0) and contact (MgDMP+, CaDMP+) ion-pairs; the degree of ion association is 20–27 % at 2:1 salt:DMP molar ratio for the bivalent ions. Comparison to literature results suggests the formation constant of MgDMP+ to be a good estimate for the binding of Mg2+ to RNA. From the concentration dependence of the rotational relaxation time of the ion-pairs, we find ion-pair dissociation rates to follow the order Mg2+ ≪ Ca2+ < Na+. Strikingly, our data suggest that the overall ion-pair dissociation dynamics are governed by an ion-pair metathesis reaction, which provides a different pathway for the binding of ions by DMP–
The neutralization of tricalcium aluminate hexahydrate and its spontaneous transformation into Friedel's salt, a layered double hydroxide
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