Spectroscopic studies of fluorenone derivatives

The absorption and steady-state fluorescence spectra of fluorenone, 1-hydro xyfluorenone, and 3-dimethylaminofluorenone have been obtained for various concentrations in a series of non-polar and polar solvents. The substituent s (-OH and -N(CH3)(2)) as the electron-donating functional groups cause a l arge shift of the longwave absorption band and Stokes' shift of the monomer - and excimer-fluorescence bands in comparison with fluorenone. The total e mission spectrum of 3-dimethylaminoflourenone in polar aprotic solvents exh ibits a new band at lambda congruent to 500 nm originating form the emissio n of the twisted intramolecular charge transfer (TICT) isomer. The elicited state dipole moments of the emiting species of the molecule studied are de termined using the solvatation shift method and calculated values of the gr ound state dipole moments.