FLUORESCENCE FROM THE TWISTED INTRAMOLECULAR CHARGE-TRANSFER COMPOUNDBIS(4,4'-DIMETHYLAMINOPHENYL)SULFONE IN ETHANOL CO2 - A PROBE OF LOCAL SOLVENT COMPOSITION
Rd. Schulte et Jf. Kauffman, FLUORESCENCE FROM THE TWISTED INTRAMOLECULAR CHARGE-TRANSFER COMPOUNDBIS(4,4'-DIMETHYLAMINOPHENYL)SULFONE IN ETHANOL CO2 - A PROBE OF LOCAL SOLVENT COMPOSITION, Applied spectroscopy, 49(1), 1995, pp. 31-39
Fluorescence spectra and decays of bis(4,4'-dimethylaminophenyl)sulfon
e (DMAPS) in mixed ethanol/CO2 supercritical fluid solution have been
examined in order to evaluate the local solvent polarity of the mixed
fluid solvents. Solvatochromic shifts and band intensities have been d
etermined by nonlinear regression analysis, and are compared with shif
ts and intensities observed in liquid n-alcohols. The spectral paramet
ers of DMAPS in the mixed supercritical fluid solvents have been used
to estimate enrichment of the local solvent composition in the polar m
odifier, under the assumption that the increase in solvent polarity ov
er that calculated for the bulk fluid is the result of augmentation of
the fluid composition in the region immediately surrounding the solut
e molecule. The analysis indicates that the local composition is enric
hed by a factor of five to ten over the bulk composition.