The rotational dynamics of Coumarin 102 (C102) in pure decalin and pure trifluoroethanol (TFE), and of a 1:1 C102:TFE complex in decalin, are examined using time-resolved fluorescence anisotropy measurements. The rotation of C102 in decalin is well-described by the Debye-Stokes-Einstein hydrodynamic model with slip boundary conditions as is the 1:1 complex. The reduced rotation time, τr/η, of C102 in pure TFE is significantly larger than its value in pure decalin but is indistinguishable from that of the complex in decalin. These results suggest that the rotation of C102 in TFE can be interpreted as the rotation of a 1:1 C102:TFE complex following the hydrodynamic model with slip boundary conditions.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry