Electrostatic stabilization

Nucleic acid stabilization, electrostatics, structure and potential stabilization or catalysis in enzymes... 

The results are reported of a study of the effect of several glycerol ester ageing modifiers used to regulate the isobutane/air interchange on the properties of extended LDPE foams. Properties investigated included dimensional stability, electrostatic decay and mb-off of excess wax at the surface of the foam. Comparisons are made with the non-glyceride modifier, stearamide. 4refs. USA... 

By placing a CF3 substituent at the / ara-position of 20, the interaction of Na+ with the highly electronegative fluorine atoms shifts the binding site closer to the CF3 functionality (see structures in Figure 4). The distance between the Na+ and the double bond of the alkene is higher, therefore, and the stabilizing electrostatic interaction between... 

Substituents at C(2) and C(4) may affect the conformational equilibrium of 3-acyl derivatives of five-membered heterocycles and examples have been reported for furan, pyrrole, and thiophene compounds (81RCR336). Stabilizing electrostatic interactions may be the origin of the conformational behavior (80JST(67)251) of the thiophene derivatives 21 and 22, which adopt the conformation depicted. 

Using an interparticle potential, the characterization of the equilibrium state is possible by thermodynamic analysis. Van Megen and Snook [10,11] have adopted the statistical approach to predict the disorder—order phase transitions in concentrated dispersions that are stabilized electrostatically. Using the perturbation theory for the disordered phase and the cell model for the ordered phase, they have estimated the particle concentrations in the two coexisting phases when an electrostatically stabilized dispersion undergoes phase separation. Recently, Cast et al. [12] have used a similar approach to construct phase diagrams for colloidal dispersions that have free polymer molecules in solution. Using the interaction potential of Asakura... 

Potassium ATPase pumping—Structure stabilization—Electrostatic effects on the reduction potential of distant centers... 

What is the structural basis of the high phosphoryl transfer potential of ATP Because A G° depends on the difference in free energies of the products and reactants, the structures of both ATP and its hydrolysis products, ADP and Pj, must be examined to answer this question. Three factors are important resonance stabilization, electrostatic repulsion, and stabilization due to hydration. ADP and, particularly, Pj, have greater resonance stabilization than does ATP. 

At low concentrations of dissolved organic matter (DOM) (<0.01 mg of C/L) and at low ionic strength (10-3 M), the hematite particles are positively charged at this pH and are stabilized electrostatically by interacting diffuse layers with characteristic (Debye) lengths of 10 nm. As the ionic strength is increased to 10 1 M at these low DOM concentrations, the diffuse layers are compressed to 1 nm, and attractive van der Waals forces promote attachment in classical Derjaguin-Landau-Verwey-Overbeek (DLVO) destabilization by what has been termed double-layer compression. 

The contour line diagram in Fig. 8b reveals that the electronic structure of both He and N ( P) are hardly distorted in the X Z ground state of HeN". The pa-hole slightly widens on the side of the He atom (the elliptic concentration areas are shifted slightly to the back) such as to increase stabilizing electrostatic interactions. This is in line with the description given above. 

For the acid-catalyzed solvolysis reaction, the large /3-secondary and small anomeric primary KIEs were suggestive of a late transition state that is dissociative in nature. Taken into account with methanolysis data, it was determined that the reaction occurs via a Dn + mechanism with the formation of an oxocarbenium ion intermediate with finite lifetime, stabilized electrostatically by the carboxylate ion at Cl. This allowed for capture by solvent from... 

In aqueous dispersion media, the preparation of high solids dispersions that are stabilized electrostatically is often fui d by the gel-hke nature of the product. This is a consequence of the interactions between the double layers surrounding each particle. No comparable increase is evident in the viscosity of sterically stabilized dispersions at high solids content. Of course, in certain applications, such as in paints, the rheological properties exhibited by electrostatically stabilized dispersions at high solids may be a decided advantage rather than a drawback. 

---