Comparison of the Macroscopic Molecular Properties in Understanding the Structural Aspects of Mixed Aquo–Organic Binary Mixtures

Abstract

Understanding the structural aspects of aquo + organic mixtures and finding out a suitable physico-chemical parameter as a structural probe is of great importance from a theoretical and experimental point of view. Attempts have been made to derive useful relations regarding the structure of aquo + organic mixtures [ethylene glycol + water, glycerol + water, dioxane + water, acetone + water and acetonitrile + water mixtures] of widely divergent characteristics based on different macroscopic molecular properties: (i) excess thermodynamic properties of mixing, (ii) excess dielectric constants, (iii) excess polarizability volumes, (iii) correlation factor ‘g’, (v) ultrasonic sound absorption, (vi) basicity or other suitable expressions. The properties give valuable details regarding the structure of aquo + organic mixtures. Macroscopic molecular properties provide a summary of all interaction energies over a long time, but finer structural details may be available from microscopic properties (using relaxation techniques etc.). A comparison of the macroscopic and microscopic methods for the determination of structural aspects of solvent systems is presented.

The structure of and interactions in binary acetonitrile + water mixtures

“…What is not clear is why are the structural features being reflected as they are by the extrema in ε E . Kuila and Lahiri criticized the approach taken by Behera and coworkers who suggested an analogy between the permittivity and the viscosity (see below) and deduced the interactions from the extrema in the corresponding excess curves. Kuila and Lahiri showed that the theoretical premises of the Behera et al .…”

“…Kuila and Lahiri criticized the approach taken by Behera and coworkers who suggested an analogy between the permittivity and the viscosity (see below) and deduced the interactions from the extrema in the corresponding excess curves. Kuila and Lahiri showed that the theoretical premises of the Behera et al . expressions for the excess functions were wrong, and their approach did not shed any light on the structure of the aqueous–organic co‐solvent mixtures.…”

“…expressions for the excess functions were wrong, and their approach did not shed any light on the structure of the aqueous–organic co‐solvent mixtures. However, Kuila and Lahiri dealt with many diverse aqueous–organic co‐solvent mixtures and too many physical properties of them, so that no clear conclusions concerning the structure of aqueous AN mixtures could be derived from their paper.…”

Fluorogenic affinity label for the facile, rapid imaging of proteins in live cells

“…The ultraviolet–visible spectrum of the quinoid is characterized by a relative absorbance maximum at ~500 nm, which is absent in the spectrum of the lactone 27. The value of ε was varied by altering dioxane/water ratios 28. We found that formation of the less polar lactones of unmasked 1 and 13 , which contain a urea moiety, is favorable in solutions of higher polarity than with compound 12 (Figure 4).…”

Molecular Dynamics and Entropy Effects in Hydrogen-Bonded Supramolecular PolymerN,N′-Di(2-methyl-2-pentylheptyl)urea Dissolved in Nonpolar Medium

“…The static dielectric permittivity values for neat acetonitrile are marked in Figure 6, at several temperatures. [44][45][46][47][48] As can be clearly seen in the figure, the temperature variation of ε s (T) for acetonitrile and MPHU + CCl 4 solution of x ) 0.1, two liquids of very similar static permittivity values, are essentially different. This fact reflects the difference in the thermodynamic consequences of the orientational behavior of the entities formed in these two liquids.…”