Taft correlations solvatochromatic

Ab initio SCRF/MO methods have been applied to the hydrolysis and methanol-ysis of methanesulfonyl chloride (334). ° The aminolysis by aromatic amines of sulfonyl and acyl chlorides has been examined in terms of solvent parameters, the former being the more solvent-dependent process.Solvent effects on the reactions of dansyl chloride (335) with substituted pyridines in MeOH-MeCN were studied using two parameters of Taft s solvatochromatic correlation and four parameters of the Kirkwood-Onsager, Parker, Marcus and Hildebrand equations. MeCN solvent molecules accelerate charge separation of the reactants and stabilize the transition... 

The terms n, a. and g are empirical solvent parameters developed by Taft and Kamlet (7). The fluoresence emission maximum of probe 1 in pure organic solvent defines the pure solvent reference line in Figure 1. When probe 1 is covalently attached to a polymer backbone which in turn is immersed in solvent, the deviation in fluorescence emission wavelength from the pure solvent correlation line reveals how the polymer perturbs the microenvironment of the probe. This microenvironment can vary from pure solvent-like to one dominated by the polymer backbone. The fluorescence emission of the probe in dry polymer is also indicated in the figure. A summary of the solvatochromatic data is discussed below. 

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