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Intramolecular exciplexes based on benzoxazole: photophysics and applications as fluorescent cation sensors


, : Intramolecular exciplexes based on benzoxazole: photophysics and applications as fluorescent cation sensors. Photochemical & Photobiological Sciences 7(5): 633-641

Exciplex behaviour of three benzoxazole derivatives has been detected and intensively investigated by means of steady-state and time-resolved fluorescence techniques and transient absorption spectroscopy. The fluorescence of these compounds shows the properties which are typical for the excited state charge transfer complexes (exciplexes). Besides of the short wavelength fluorescence, which is similar in spectral distribution to the fluorescence of the electron acceptor (2-p-tolyl-benzoxazole), the red shifted, broad and structureless emission band is observed in solvents of low and medium polarity. The detailed analysis of the fluorescence data shows that the ratio of the CT and LE fluorescence initially increases with increasing solvent polarity, achieves a maximum, and drops for more polar solvents (epsilon(s) = 7). Similar behaviour is observed for the exciplex fluorescence lifetimes. The overall fluorescence and the relative intersystem crossing quantum yields show the decrease of these values with increasing solvent polarity. These observations have been explained on the basis of Marcus-type theory for nonradiative charge transfer rate constants. Increasing solvent polarity strongly accelerates the back electron transfer process which recovers the whole molecule in the ground state. The probability of the compact exciplex formation (i.e. sandwich-type structures) depends on solvent viscosity and degree of freedom of the bending of the saturated linker. The compound containing crown ether as a donor subunit may be used as a fluorescent indicator of inorganic cations (barium and lithium). We found an effective complexation of the compound in the ground state with barium and lithium cations. The complex is also stable in the excited state which manifests itself in strong increase of the fluorescence intensity.

US$19.90

PMID: 18465020

DOI: 10.1039/b719141c


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Fillastre, J.P.; Baud, L.; Baumelou, A.; Blanchard, J.; Bonvalet, J.P.; Champey, Y.; Druet, P.; Glomot, R.; Imbs, J.L.; Lagier, G., 1986: Detection of drug-induced nephrotoxicity. This is a report of a round table organized during the second meeting of Clinical Pharmacology held in Giens (France) in September 1985. At the beginning of the meeting, the clinical aspects of drug-induced nephrotoxicity were reviewed. Thus we tr...

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Kozlowski, G.P.; Coates, P.W., 1985: Ependymoneuronal specializations between LHRH fibers and cells of the cerebroventricular system. Light- and electron-microscopic immunocytochemistry (LM-ICC and EM-ICC) were used to visualize luteinizing hormone-releasing hormone (LHRH) in fibres associated with ventricular ependyma and tanycytes of the median eminence. LM-ICC suggests that L...

Neri G., 1995: A seismological contribution to geodynamic modelling of Italy and surroundings. International Union of Geodesy and Geophysics, General Assembly: eek B; Pages 366. 1995.

Panayi, V.; Froud, O.J.; Vine, L.; Laurent, P.; Woolson, K.L.; Hunter, J.G.; Madden, R.G.; Miller, C.; Palmer, J.; Harris, N.; Mathew, J.; Stableforth, B.; Murray, I.A.; Dalton, H.R., 2015: The natural history of autoimmune hepatitis presenting with jaundice. Forty percent of patients with autoimmune hepatitis (AIH) present with acute jaundice/hepatitis. Such patients, when treated promptly, are thought to have a good prognosis. The objective of this study was to describe the natural history of AIH in...

Powell, C.; Rushforth, H., 1996: Paediatric intensive care: what is the solution?. British Journal of Nursing 5(11): 652-652