Photophysical characteristics of diphenyl carbazide-laser flash photolysisand fluorescence studies

The photophysical characteristics of diphenyl carbazide (DPC) have been inv estigated in various protic and aprotic polar solvents. Shifts in fluoresce nce spectra showed good linear fits with the E-T(30) polarity scale and the solvent polarity function Delta f. The emitter state is identified as havi ng charge transfer character and is estimated to have a dipole moment of si milar to 8.6 D. Excited state lifetimes determined from transient absorptio n and fluorescence lifetime studies match well. Triplet-triplet absorption and phosphorescence emission (at 77 K) have been characterized and the trip let state energy is estimated to be similar to 80 kcal/mol. Our experimenta l results show that DPC behaves more like a keto compound than a hydrazide derivative. (C) 2000 Elsevier Science B.V. All rights reserved.