Perylene, resonance energy

Figure 6.12 Resonance energy transfer causing enhancement of fluorescence in perylene-chloroanthracene system.

Similar calculations of the loss of resonance energy due to overcrowding in 5,6-7,8-dibenzoperylene (7) and 1,12-5,6-7,8-tribenzo-perylene (8) (Ah and Coulson, 1959) show that the increased size and... 

The critical radius 117 of the resonant energy transfer from the triplet state of benzophenone to the singlet state of perylene at 77 in a mixture of chloroform and ether has been determined to be 68 A, a value similar to those obtained for related pairs of molecules.118... 

Li Z, Lu J, Li S, Qin S, Qin Y. Orderly ultra-thin films based on perylene/poly(V-vinyl carbazole) assembled with layered double hydroxide nanosheets 2D fluorescence resonance energy transfer and reversible fluorescence response for volatile orgaiuc compounds. Adv Mater 2012 24(45) 6053-7. 

A number of perylene derivatives undergo cyclo addition reaction. Hern-don has shown that the free energies of activation of the reaction of MA with aromatic hydrocarbon has a linear relationship with calculated resonance energy differences. This approach has significant prediction value (see Table 4.5). Recently, kinetic studies of the DA reaction of maleic anhydride with polycyclic aromatics have been reported. 

Supporting evidence for the resonance mechanism comes from experiments in which the solvent has been varied. The predicted proportionality of the rate constant to the overlap Integral J has been directly shown in a study of a donor-acceptor pair (both steroids) in a series of solvents in which J varied 40-fold (Figure 6.19) [40]. The effect of solvent viscosity has also been studied. Since energy transfer by the resonance mechanism does not require collision, the rate would be expected to be independent of solvent viscosity. This has been verified for the quenching by perylene of fluorescence emission from excited 1-chloroanthracene [41] where the rate constant, which is about 2 x lO" M s (about ten times kp) in benzene, is no lower in liquid paraffin whose viscosity is around 100 times larger, nor even in a glass at 90 K. 

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