Charge transfer fluorescence

Valeur B. and Leray I. (2001) PCT (Photo-induced Charge Transfer) Fluorescent Molecular Sensors for Cation Recognition, in Valeur B. and Brochon J. C. (Eds),... 

S. Tazuke and R. K. Guo, Effects of polymer microenvironment on the thermodynamics of the twisted intramolecular charge transfer fluorescence, Macromolecules 23, 719 (1990). 

K. Hamasaki, H. Ikeda, A. Nakamura, A. Ueno, F. Toda, I. Suzuki, andT. Osa, Fluorescence sensors of molecular recognition. Modified cyclodextrins capable of exhibiting guest-responsive twisted intramolecular charge transfer fluorescence, /. Am. Chem. Soc. 775,5035-5040(1993). 

In one of the first experimental studies where ion radical annihilation in solution was considered as an emissive possibility, Yamamato, Nakato, and Tsubomura61 found that Y,Y,Y, Y -tetramethyl-p-phenyl-enediamine (TMPD) and pyrene when irradiated in the ultraviolet in a glass at low temperature formed Wurster s blue cation radical, pyrene anion radical, and solvated electrons. When the glass was warmed, thermoluminescence was observed. A similar emission was observed when a previously irradiated mixture of TMPD and 2-methylnaph-thalene was warmed. The emission in both instances was ascribed to charge-transfer fluorescence resulting from combination of a cation radical with an anion radical. 

As already discussed in Section II, larger systems like the diphenylsul-fones also exhibit a charge-transfer fluorescence, and the donor can be shown not to be the amino but the entire anilino group. In the case of the anilino-substituted anthracene ADMA this has directly been demonstrated by the bridged model compound ADMAB. 

Fig. 18 (a) Values of the electronic coupling matrix element, Vel, calculated from the charge transfer fluorescence data for 18(h) in butyl ether.110... 

Figure 23. Values of the electronic coupling elements, V i, calculated from charge transfer fluorescence data for 23(n) in n-butylether 75],...

Fig. 3. Schematic illustration of non-radiative election transfer (horizontal arrows) in the normal (left) and inverted (right) Marcus regions. Associated with each vibronic state is a stack of sublevels representing low-frequency (mainly) solvent modes. In the initial state only one vibrational mode, with j = 0, is mainly occupied, whereas in the final state various vibrational modes, with y = 0,1,2..., may be accessible. Diagonal arrows (in the inverted Marcus region) correspond to radiative electron transfer (charge-transfer fluorescence). Adapted from [55].

In nonpolar solvents below 150°K another fluorescence than the exciplex fluorescence was observed and it was ascribed to intramolecular charge-transfer fluorescence between the dlcyano-anthracene and naphtalene moieties (34). 

Miscibility of PI blends of different structures was reported by Hasegawa et al. [1991] using charge-transfer fluorescence spectra, dynamic mechanical analysis, and phase-contrast microscopy. These blends were BPDA/PDA PI with PMDA/PDA and PMDA/ODA PFs (BPDA = biphenyltetracarboxylic dianhydride PDA = p-phenylene diamine ODA = oxydianUine PMDA = pyromellitic dianhydride). Two patents issued virtually simultaneously noting the utility of miscible PI blends for gas separating membranes [Burgoyne et al., 1991 Kohn et al., 1991]. 

Measurement of the heat evolved is used for determination of energy levels of intermediates (including the energy associated with chromophore-solvent interactions), provided that the quantum yields for the reactions are known. Conversely, if the energy level of the intermediates is known from other spectroscopic techniques, the determination of quantum yields is possible, for example for isomerization, charge transfer, fluorescence, intersystem crossing and energy transfer processes. 

Al-Hassan, K., Klein, Uwe, K. A., and Suwaiyan, A, Normal and twisted intramolecular charge-transfer fluorescence of 4-dimethylaminobenzonitrile in a-cyclodextrin cavities, Chem. Phys. Lett., 212, 581,1993. 

Setaka W, Hamada N, Kabuto C, Kira M (2005) Intramolecular charge-transfer fluorescence of l-phenyltridecamethylbicyclo[2.2.2]octasilane. Chem Commun 4666... 

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