Solute aggregation

Bensasson R V, Bienvenue E, Dellinger M, Leach S and Seta P 1994 Cgg in model biological systems. A visible-UV absorption study of solvent-dependent parameters and solute aggregation J. Phys. Chem. 98 3492-5000... 

M. Grell, D.D.C. Bradley, X. Long, T. Chamberlain, M. Inbasekaran, E.P. Woo, and M. Soliman, Chain geometry, solution aggregation and enhanced dichroism in the liquid-crystalline conjugated polymer poly(9,9-dioctylfluorene), Acta Polym., 49 439-444, 1998. 

Lahn B, Rehahn M. Coordination polymers from kinetically labile copper(I) and silver(I) complexes true macromolecules or solution aggregates Macromol Symp 2001 163 157-176. 

Methyl ethyl ketone 19.0 Reaction Moderate Clear solution Aggregation... 

NMR Spectra. Uskokovic was probably the first to report the difference in the H-NMR spectra of an optically pure compound and its racemate (53). As illustrated in Scheme 32, the spectra of optically pure dihy-droquinine and the racemate differ significantly when taken at the same concentration in chloroform-d. The spectrum of the partially resolved compound affords two sets of peaks whose areas are proportional to the relative amount of each enantiomer. These observations can be understood by considering the presence of the solute-solute interactions of the enantiomers. Thus, to the extent that there is some solute aggregation, enantiomers may exhibit different spectra. 

A spectrophotometric investigation of the ground-state absorption of benzophenone in pure SC CO2 and in the presence of 2-propanol was performed in order to determine both benzophenone solubility and the potential for solute/solute or co-solvent/solute aggregations. Linear Beer s law plots of absorbance versus concentration of benzophenone over a concentration range of 1-15 mM in SC OO2 insured that the ketone was fully disolved and in a non-associated form under the conditions of the laser experiments (- 10 mM). Analysis of the absorption spectrum of benzophenone in SC CO2 ranging from high to low pressure, resulted in absorption bands nearly... 

In the weak-interaction model (85) developed in the previous section to explain ion-pairing in metal-ammonia solutions, aggregation interactions involving Ms+ and es are relatively weak, and leave the isolated solvated electron properties virtually intact. However, a major difficulty (29,54,134) arises with the type of model when one considers the precise nature of the corresponding electron spin-pairing interaction in ammonia solutions. It is worth expanding on this issue because it probably remains one of the fundamental dilemmas of metal-ammonia solutions in the dilute range (54). 

A further example where specific effects, in this case solute-solute aggregation effects, are noticeable is the VCD spectra of (—)-3-butyn-2-ol in CC14 solution at different... 

An important point in the science of conjugated polymers is the dependence of their optical properties as a response to their physical state (solution, aggregated, liquid crystalline, solid state, thermal treatment) [50]. Processable PPEs, particularly dialkoxy-PPEs, have been known since the early 1990s [1], and their spectroscopic behavior has been studied both in... 

Solvophobicity — The effect that a relative unfavorable solvation free energy leads to solute aggregation. See -5- hydrophobic effect. 

Wilsons equation and the modification proposed by Renon and Prausnitz (8) use the local mole fraction concept, produced because molecules in solution aggregate as a result of the variation in intermo-lecular forces. The local mole fraction concept results in a more useful description of the behavior of molecules in a non-ideal mixture. 

Figure 8.20, panel B, shows the character of a film formed from aggregates in solution. Aggregates have a low and nonuniform density... 

Partial molar volume is predicted in reasonable agreement with experiment, and solute-solute aggregation is also predicted as suggested by recent excimer fluorescence results. We conclude that integral equation theories are useful in revealing solvation structures of supercritical solutions. 

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