Solvation studies

Momany, F. A., R. Rone, H. Kunz, R. F. Frey, S. Q. Newton, and L. Schafer. 1993. Geometry Optimization, Energetics and Solvation Studies on Four- and Five-mem-bered Cyclic and Disulfide-bridged Peptides, Using the Programs QUANTA3.3 and CHARMm 22. J. Mol. Struct. 286, 1-18. 

The most common approach to solvation studies using an implicit solvent is to add a self-consistent reaction field (SCRF) term to an ab initio (or semi-empirical) calculation. One of the problems with SCRF methods is the number of different possible approaches. Orozco and Luque28 and Colominas et al27 found that 6-31G ab initio calculations with the polarizable continuum model (PCM) method of Miertius, Scrocco, and Tomasi (referred to in these papers as the MST method)45 gave results in reasonable agreement with the MD-FEP results, but the AM1-AMSOL method differed by a number of kJ/mol, and sometimes gave qualitatively wrong results. 

Acetonitrile has been selected as the solvent in this study since it is a possible candidate for a nonaqueous electrolyte battery (5). From this viewpoint, acetonitrile has several attractive physical properties, as shown in Table I. It has a useful liquid state range and a reasonably low vapor pressure and viscosity at ambient temperature. In addition, many common electrolytes are soluble in acetonitrile. Acetonitrile is a good model solvent for solvation studies, as the molecule is a linear aprotic dipole. 

Fratiello, A., Nuclear Magnetic Resonance Cation Solvation Studies. 17 57... 

L. Frediani, B. Mennucci, R. Cammi, Quantum-mechanical continuum solvation study of the polarizability of halides at the water/air interface. J. Phys. Chem. B 108, 13796 (2004)... 

Dogonadze, R.R. et al. The Chemical Physics of Solvation. Studies in Physical and Theoretical Chemistry, Amsterdam Elsevier, Vol. 38-ABC, 1985. 

In order for computations of nucleic acid bases to have relevancy to biological questions, the role of solvent (water) must be considered. Computational solvation studies of base pairs are fairly limited. 

Several methods involve a study of the properties of solutions in equilibrium and are hence reasonably described as thermodynamic. These methods usually involve thermal measurements, as with the heat and entropy of solvation. Partial molar volume, compressibility, ionic activity, and dielectric measurements can make contributions to solvation studies and are in this group. 

It has been often suggested that nuclear resonance might be used to gain information in solvation studies. Thus, in hydroxylic solvents, electron shielding around the proton should be affected by ions and thus, in terms of changes in nuclear resonance frequencies, solvation-bound water and free water should be distinguishable. It turns... 

One of the challenges of solvation studies consists in separating effects among the ions of a salt (e.g., those due to the anion and those due to the cation) and this difficulty, that of determining the individual solvation heats (see Section 2.15), invades most methods devoted to the determination of individual ionic properties (Fig. 2.46). When it comes to the solvation number of an ion, an unambiguous determination is even more difficult because not all workers in the field understand the importance of distinguishing the coordination number (the nearest-neighbor first-layer number) from... 

Kuznetsov AM, Ulstrup J, Vorotyntsev MA (1988) Solvent effects in charge transfer processes. In Dogonadze RR, Kalman E, Komyshev AA, Ulstrup J (eds) The chemical physics of solvation. Studies in physical and theoretical chemistry, vol 38, chap 3, Elsevier, Amsterdam Gerson F, Wellauer T, Oliver AM, Paddon-Row MN (1990) Helv Chim Acta 73 1586 Liang N, Miller JR, Closs GL (1990) J Am Chem soc 112 5353 Jordan KD, Paddon-Row MN (1992) Chem Rev 92 395 Kochi JK (1988) Angew Chem 100 1331 Int Ed Engl 27 1227 Wasielewski MR (1992) Chem Rev 92 435... 

Although several other methods have been used in such solvation studies, NMR spectroscopy seems to be the most useful. 

Applications of the Born—Kirkwood-Onsager model at the ab initio level include investigations of solvation effects on sulfamic acid and its zwitterion,23i an examination of the infrared spectra of formamide and formamidic acid,222 and a number of studies focusing on heterocyclic tautomeric equilibria.222,232,233 a more detailed comparison of some of the heterocyclic results is given later. The gas phase dipole moment depends on basis set, and systematic studies of this dependence are available. Furthermore, the effects of basis set choice and level of correlation analysis have been explored in solvation studies as well,222,233 but studies to permit identification of particular trends in their impact on the solvation portion of the calculation are as yet insufficient. 

Even the simplest level of understanding of most reactions of interest in biochemistry requires taking some account of the effects of aqueous solvation on both structure and dynamics. In this section, we consider examples of solvation studies on three biomolecules dopamine, glucose, and thymine. 

Solvation Studies. The fluoresence emission maximum of polymer bound probe provides a measure of the ability of solvent molecules to solvate polymer chains In the network. The solvatochromlc shift of probe 1 has been linearly related to a wide variety of organic solvents using the empirical relationship shown In Equation 2 (6). 

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