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The ability of a carbanion to displace the leaving group in a barrierless process is examined. It is found that the concerted nature of the reaction depends on the conditions used to generate the carbanion.

We produced gaseous hydrated clusters of sulfate and oxalate anions S[O.sub.4.sup.2-]-[([H.sub.2]O).sub.n] and [C.sub.2][O.sub.4.sup.2-][([H.sub.2]O).sub.n]], where n = 4 to 40]. Photoelectron spectra of these clusters revealed that the solute dianions were in the center of the water cluster, [([H.sub.2]O).sub.n]. For small clusters, these spectra were characteristic of the respective solutes, but beyond the first solvation shell (n ≅ 12), features in the spectra from the solutes were diminished and a new feature from ionization of water emerged, analogous to bulk aqueous solutions. For large dusters with dimensions greater than 1 nanometer, the solute photoemission features disappeared and the spectra were dominated by the ionization of water as the solvent coverage increased. A smooth transition from gas-phase clusters to behavior of electrolyte solutions was clearly revealed, and the large solvated clusters can be used as molecular models to investigate the photophysics and chemistry of aqueous electrolyte solutions., Cations often exhibit definitive solvation shells both in bulk aqueous solutions (1, 2) and in water clusters (3) because of their small sizes and strong solute-water interactions. However, the solvation [...]

Research is presented describing the study of ionic species to determine levels of free energy absolute solvation using extrapolation techniques.

Limitations of the Poisson-Boltzman theory in the interpretation of polyelectrolyte properties are discussed. Three models are presented to explain the behavior of the multivalent, asymmetric, and micelle-shaped polyelectrolytes.

Microwave heating can be applied to materials with certain absorption and thermal conduction properties, including ceramic materials. A numerical model, simulating the defect perturbations and fluxes resulting from microwave excitation of ionic crystalline solids, has been developed. The pondermotive effect is visualized and, and the resulting driving force for mass transport is calculated.

(Hydroxy(mesyloxy)iodo)benzene (HMIB) and its tosyloxy analog (HTIB) are stable, crystalline organoiodine complexes which are soluble in water at natural pH. UV-vis and NMR spectroscopy was used, together with potentiometric titration data, to show the presence of dimeric mu-oxodiiodine species in aqueous solution. The data shows that HMIB and HTIB occur in aqueous solution as fully solvated ions, a free hydroxy(phenyl)iodonium ion and an organosulfonate ion.

The isolation of an ionophore metal complex structure was defined by NMR in a solution based on NOE-derived distances and was clarified by MD computations. The conformational space of salinomycin is inhibited by combining the sodium ion with a coordination pattern of a distorted pentagonal pyramid. It was proved that the description of the NOE-derived solution structure provides information on the coordination pattern in the solution. Major hinge torsions which influence the operating factors and the chronology of the unfolding path were obtained for salinomycin by using a dynamic model.

A quantum two valence bond state Hamiltonian was used in combination with a dielectric continuum solvent analysis to study SN1 ionic dissociations for the series tert-butyl chloride, -bromide, and -iodide. Two-dimensional free energy surfaces were derived and analyzed in terms of a collective solvent coordinate S and internuclear separation r which facilitate a detailed transition state (TS) structure and free energetics evaluation. The TS structure and activation features of the tert-butyl halide series in a fixed solvent was attributed to decreasing electronic coupling variation.

An investigation on the interfacial properties of nanometric colloidal silica dispersions in the presence of a cationic surfactant is reported. The result of the experimental work show how dispersed nanoparticles in an aqueous phase could modify the interfacial properties of the liquid/air or liquid/liquid systems if their surface is modified by the presence of an ionic surfactant.

A study is conducted to show that a new sol-gel precursor consists of positively charged polyhedral cubelike silsesquioxanes. The result reveals that over the course of condensation of sols, the refractive index of the modes attributed to the polysilsesquioxanes species exhibited strong dispersion, which led to a shift of the vibrational band position in the experimental ATR spectra.

The suitability of ionic liquids for dissolving and regenerating silkworm (Bombyx mori) silk and the structural properties of silk films cast from ionic liquid solutions are examined. The results verify that ionic liquids are viable solvents systems for dissolving and regenerating silk fibroin.

The ionic liquids based on the SeCN(super -)/(SeCN)(sub 3)(super -) redox couple can be employed as mediators for high-efficiency dye-sensitized solar cells. An alternative redox couple are identified that can rival and even exceed the performance of the iodide/triiodide couple even at full sunlight.

Fundamental expressions for analyzing potential modulated fluorescence (PMF) responses were derived within the framework of a phenomenological model for adsorption and transfer of ionic species across polarized liquid/liquid interfaces. Studies performed at various Galvani potential differences clearly confirm that the adsorption can take place at two distinctive planes located at the aqueous and organic sides of the interface.

Clusters consisting of finite collections (2 to 1000) of atoms or molecules are easily generated in the gas phase with modern experimental methods. It is often claimed that the study [...]