Resolution and Characterization of Rotamers in 1-Phenyl-2-(2-anthryl)ethylene

Abstract

Time-resolved spectroscopic techniques have enabled the components of the heterogeneous fluorescence of 1-phenyl-2-(2-anthryl)ethylene to be resolved in toluene solution. The emission is rationalized in terms of two species with lifetimes and quantum yields at 25 °C measured to be τ1 = 8.3 ns and ϕ1 = 0.24 and τ2 = 28.25 ns and ϕ2 = 0.97, each with its own distinctive fluorescence and absorption spectra. It is shown that the difference in fluorescence decay times of these two rotameric species is attributable to a difference in their nonradiative rates. Temperature dependence measurements of fluorescence decay have enabled the enthalpy of the equilibrium in the ground state to be estimated a..