Triplet State of Benzene

Abstract

The sensitization of biacetyl fluorescence and phosphorescence using benzene as donor has been studied at 25°C in aerated and de-aerated hexane solutions. Electronic energy transfer from the lowest excited singlet state of benzene to biacetyl producing either the first or second excited singlet state of biacetyl proceeds with a rate constant (3.3×1010 liter moles—1 sec—1), which is consistent with a diffusion controlled process. No evidence for energy transfer from triplet benzene to biacetyl has been found in fluid solution. However, in rigid media, transfer from triplet benzene has been established with a transfer distance of ∼10 Å. The surprising lack of evidence for triplet benzene in fluid solution is discussed in the light of previous work.