ISSN:
0894-3230
Schlagwort(e):
Organic Chemistry
;
Physical Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
The relative basicities of six monosubstituted dipolar trimethylamines (XCH2NMe2) were determined in nine different solvents from potentiometric titration. Solvation effects on basicity variations were analyzed by the solvatochromic parameters (π*, α and β). Non-specific solvation of the substituted dimethylammonium ions is not reflected adequately by the solvent's dipolarity-polarizability constant, π*. A better representation of non-specific interaction between solvents and the monosubstituted dipolar trimethylammonium ions is gained from the product of π* and the solvent dipole moment (μ). For these ions where the dipolar substituents are separated from the reaction center by one methylene unit, there is an interaction between the charge of the ammonium ion and the dipolar substituent. As a result, solvent molecules must not only solvate the dipolar substituents, but must also gain access between the lines of force of the dipolar substituent and the charge. Bulky solvents, such as nitrobenzene, cannot access adequately the region between the dipolar substituents and the reaction center to accomplish similar solvation as less bulky solvents.
Zusätzliches Material:
2 Tab.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/poc.610070203
