STUDY OF PREFERENTIAL SOLVATION IN BINARY SOLVENT MIXTURES BY THE FLUORESCENCE-DETECTED MAGNETIC-FIELD EFFECT

It has been found that the magnetic field effect detected by fluoresce nce of the pyrene-N,N-dimethylaniline exciplex in binary liquid mixtur es containing components of significantly different relative permittiv ities depends on V-mP(delta(P) - delta(N))(2) values which appear in H ildebrand's theory. Here V-mP is the molar volume of a polar component and delta(P), and delta(N), are the solubility parameters of polar an d non-polar components, respectively. The results suggest that the pre ferential solvation of radical-ion pairs in mixtures may be affected b y their concentration fluctuations. The characteristic dimension of po lar microdomains produced around radical ions was determined by the ma gnetic-field-effect technique to be ca. 50 Angstrom.