Solvation INDEX

Correlation methods discussed include basic mathematical and numerical techniques, and approaches based on reference substances, empirical equations, nomographs, group contributions, linear solvation energy relationships, molecular connectivity indexes, and graph theory. Chemical data correlation foundations in classical, molecular, and statistical thermodynamics are introduced. 

In Raman spectroscopy the intensity of scattered radiation depends not only on the polarizability and concentration of the analyte molecules, but also on the optical properties of the sample and the adjustment of the instrument. Absolute Raman intensities are not, therefore, inherently a very accurate measure of concentration. These intensities are, of course, useful for quantification under well-defined experimental conditions and for well characterized samples otherwise relative intensities should be used instead. Raman bands of the major component, the solvent, or another component of known concentration can be used as internal standards. For isotropic phases, intensity ratios of Raman bands of the analyte and the reference compound depend linearly on the concentration ratio over a wide concentration range and are, therefore, very well-suited for quantification. Changes of temperature and the refractive index of the sample can, however, influence Raman intensities, and the band positions can be shifted by different solvation at higher concentrations or... 

As in isocratic mode, the estimate of log P is indirect and based on the construction of a linear retention model between a retention property characteristic of the solute (logkw) and a training set with known logP ci values. To assess the most performing procedures, the three hydrophobicity indexes (( )o, CHI and logkw) were compared on the basis of the solvation equation [41]. These parameters were significantly inter-related with each other, but not identical. Each parameter was related to log P with values between 0.76 and 0.88 for the 55 tested compounds fitting quality associated with the compound nature. 

The behavior of the different amines depends on at least four factors basicity, nucleophilicity, steric hindrance and solvation. In the literature (16), 126 aliphatic and aromatic amines have been classified by a statistical analysis of the data for the following parameters molar mass (mm), refractive index (nD), density (d), boiling point (bp), molar volume, and pKa. On such a premise, a Cartesian co-ordinate graph places the amines in four quadrants (16). In our preliminary tests, amines representative of each quadrant have been investigated, and chosen by consideration of their toxicity, commercial availability and price (Table 1). 

The general or universal effects in intermolecular interactions are determined by the electronic polarizability of solvent (refraction index n0) and the molecular polarity (which results from the reorientation of solvent dipoles in solution) described by dielectric constant z. These parameters describe collective effects in solvate s shell. In contrast, specific interactions are produced by one or few neighboring molecules, and are determined by the specific chemical properties of both the solute and the solvent. Specific effects can be due to hydrogen bonding, preferential solvation, acid-base chemistry, or charge transfer interactions. 

The existence of critical solvation numbers for a given process to happen is an important concept. Quantum chemical calculations using ancillary solvent molecules usually produce drastic changes on the electronic nature of saddle points of index one (SPi-1) when comparisons are made with those that have been determined in absence of such solvent molecules. Such results can not be used to show the lack of invariance of a given quantum transition structure without further ado. Solvent cluster calculations must be carefully matched with experimental information on such species, they cannot be used to represent solvation effects in condensed phases. 

Chatteijee, A., Balaji, T., Matsunaga, H., and Mizukami, F. 2006. A reactivity index study to monitor the role of solvation on the interaction of the chromophores with amino-functional silanol surface for colorimetric sensors. J. Mol. Graphics Model. 25 208-218. 

Library of Congress Cataloging in Publication Data. Main entry under title Structure of liquids. (Topics in current chemistry 60) Bibliographic p. Includes index. CONTENTS Schuster, P., Jakubetz, W., and Marius, W. Molecular models for the solvation of small ions and polar molecules. — Rice, S. A. Conjectures on the structure of amorphous... 

These expressions appear more applieable to nonpolar solvents or mixtures than to polar solvents. The nature of the solvation process (and the radii and so forth of the solvated reactants) may stay approximately constant in the first situation but almost certainly will not in the seeond. The function (E>op A ) features in the reorganisation term Xq which is used for estimating rate constants for redox reactions (Eqn. 5.23). is the optical dielectric constant and Dj the static dielectric constant (= refractive index ). 

Ke equilibrium constant kr, rate constant Rf rate of flow, tR, retention time Vg speolflo retention volume I, retention index, B, binding S, solvation R, reactivity ct, charge transfer. 

Solubilities, in water, ethanol, and ethanol-water mixtures, have been reported for [Fe(phen)3]-(0104)2, [Fe(phen)3]2[Fe(CN)6], and [Fe(phen)3][Fe(phen)(CN)4]. Solubilities of salts of several iron(II) iiimine complexes have been measured in a range of binary aqueous solvent mixtures in order to estimate transfer chemical potentials and thus obtain quantitative data on solvation and an overall picture of how solvation is affected by the nature of the ligand and the nature of the mixed solvent medium. Table 8 acts as an index of reports of such data published since 1986 earlier data may be tracked through the references cited below Table 8, and through the review of the overall pattern for iron(II) and iron(III) complexes (cf. Figure 1 in Section 5.4.1.7 above) published recently. ... 

PG Muijselaar, HA Claessens, CA Cramers. Characterization of pseudostation-ary phases in micellar electrokinetic chromatography by applying linear solvation-energy relationships and retention indexes. Anal. Chem. 69 1184—1191... 

When acetic acid is diffusing from a 1.9 iV solution in water into benzene, spontaneous emulsion forms on the aqueous side of the interface, accompanied by a little interfacial turbulence. Results can be obtained with this system, however, if in analysing the refractive index gradient near the surface a correction is made for the spontaneous emulsion the rate of transfer is then in excellent agreement (57) with Eq. (20) (Fig. 6). Consequently there is no appreciable energy barrier due to re-solvation of the acetic acid molecules at the interface, nor does the spontaneous emulsion affect the transfer. With a monolayer of sodium lauryl... 

A quantitative measure of interaction between polymer and monomer in solution can be expressed by a value of preferential solvation. Preferential solvation can be calculated from the measurements of refractive index increments in dialysis experiments. This experiment can be illustrated as in Figure 3.1. 

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