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- W1984583221 endingPage "6949" @default.
- W1984583221 startingPage "6942" @default.
- W1984583221 abstract "The static and dynamic fluorescence behavior of a series of hexaalkyl benzenehexacarboxylates (R(6)BHC; R = methyl (Me), tert-butyl (tBu), (-)-menthyl (Men), (-)-bornyl (Bor), (-)-1-methylheptyl (MHp), neopentyl (neoPn), and 2-adamantyl (Ad)) was studied by steady-state and time-resolved fluorescence spectroscopy. Dual fluorescence from both the partially relaxed metastable Franck-Condon-like (FC') and the fully relaxed (RX) state was observed for tBu(6)BHC, Men(6)BHC, Bor(6)BHC, MHp(6)BHC, neoPn(6)BHC, and Ad(6)BHC, whereas only single fluorescence from the RX state was observed for Me(6)BHC. Picosecond time-resolved fluorescence spectroscopic measurements clearly demonstrated that the initially formed Franck-Condon (FC) state sequentially converts to the FC' and then to RX state, with the relaxation hindered to such an extent that it shows variation with the steric bulk of the R groups. Thus, the fluorescence lifetimes (tau's) of FC' and RX are critically dependent on the bulkiness of the R groups, varying from 17 to 130 ps and from 0.6 to 1.1 ns, respectively. The relative intensity of FC' and RX fluorescence (I(RX)/I(FC)(')) was found to be dependent on the excitation wavelength, suggesting that the conformational relaxation from the FC' to RX state can compete with the vibrational relaxation of the FC' state. The temperature and pressure dependences were studied by steady-state fluorescence spectroscopy to give the activation energies of 1-3 kcal/mol for the FC'-to-RX relaxation of congested R(6)BHCs, as well as the activation volumes of 2.0, -0.62, and 7.4 mL/mol for tBu(6)BHC, Men(6)BHC, and Bor(6)BHC at room temperature. The fluorescence anisotropy (rho), as a measure of molecular motion, was also determined to be in the ranges of 0.03-0.3 for FC' and 0.003-0.01 for RX. The much larger rho's for the FC' fluorescence by a factor of 2-100 are attributed to the shorter tau's. The I(RX)/I(F' ratio was found to be insensitive to solvent polarity, but critically dependent on solvent viscosity, exhibiting an excellent linear relationship with the reciprocal viscosity. The potential use of these sterically congested R(6)BHCs as microenvironmental viscosity probes is proposed." @default.
- W1984583221 created "2016-06-24" @default.
- W1984583221 creator A5017699354 @default.
- W1984583221 creator A5048141659 @default.
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- W1984583221 creator A5088575579 @default.
- W1984583221 creator A5091175594 @default.
- W1984583221 creator A5091257097 @default.
- W1984583221 date "2002-05-23" @default.
- W1984583221 modified "2023-10-16" @default.
- W1984583221 title "Unique Dual Fluorescence of Sterically Congested Hexaalkyl Benzenehexacarboxylates: Mechanism and Application to Viscosity Probing" @default.
- W1984583221 cites W1963981479 @default.
- W1984583221 cites W1966482728 @default.
- W1984583221 cites W1971890112 @default.
- W1984583221 cites W1974705704 @default.
- W1984583221 cites W1976175298 @default.
- W1984583221 cites W1978121709 @default.
- W1984583221 cites W1979092385 @default.
- W1984583221 cites W1979614867 @default.
- W1984583221 cites W1980188557 @default.
- W1984583221 cites W1983718246 @default.
- W1984583221 cites W1985557818 @default.
- W1984583221 cites W1985609598 @default.
- W1984583221 cites W1988650723 @default.
- W1984583221 cites W1989280947 @default.
- W1984583221 cites W1990296802 @default.
- W1984583221 cites W1990745288 @default.
- W1984583221 cites W1990788486 @default.
- W1984583221 cites W1991849200 @default.
- W1984583221 cites W1992218271 @default.
- W1984583221 cites W1999804729 @default.
- W1984583221 cites W1999882008 @default.
- W1984583221 cites W2001080208 @default.
- W1984583221 cites W2001309031 @default.
- W1984583221 cites W2004446238 @default.
- W1984583221 cites W2006985745 @default.
- W1984583221 cites W2007741875 @default.
- W1984583221 cites W2008563123 @default.
- W1984583221 cites W2013030616 @default.
- W1984583221 cites W2014496614 @default.
- W1984583221 cites W2018225146 @default.
- W1984583221 cites W2021810500 @default.
- W1984583221 cites W2022433797 @default.
- W1984583221 cites W2025253740 @default.
- W1984583221 cites W2026093435 @default.
- W1984583221 cites W2028414647 @default.
- W1984583221 cites W2032565444 @default.
- W1984583221 cites W2034487955 @default.
- W1984583221 cites W2036132799 @default.
- W1984583221 cites W2036901905 @default.
- W1984583221 cites W2038072014 @default.
- W1984583221 cites W2039200303 @default.
- W1984583221 cites W2039234588 @default.
- W1984583221 cites W2046049877 @default.
- W1984583221 cites W2046552393 @default.
- W1984583221 cites W2051691311 @default.
- W1984583221 cites W2054588951 @default.
- W1984583221 cites W2055953837 @default.
- W1984583221 cites W2062898993 @default.
- W1984583221 cites W2064052929 @default.
- W1984583221 cites W2064953308 @default.
- W1984583221 cites W2067563803 @default.
- W1984583221 cites W2069907581 @default.
- W1984583221 cites W2069981660 @default.
- W1984583221 cites W2072048480 @default.
- W1984583221 cites W2072522371 @default.
- W1984583221 cites W2073577215 @default.
- W1984583221 cites W2074580149 @default.
- W1984583221 cites W2075825779 @default.
- W1984583221 cites W2077899032 @default.
- W1984583221 cites W2080986360 @default.
- W1984583221 cites W2082403933 @default.
- W1984583221 cites W2084570573 @default.
- W1984583221 cites W2087371702 @default.
- W1984583221 cites W2088588998 @default.
- W1984583221 cites W2088879406 @default.
- W1984583221 cites W2091798788 @default.
- W1984583221 cites W2091933978 @default.
- W1984583221 cites W2093921441 @default.
- W1984583221 cites W2108275263 @default.
- W1984583221 cites W2136094804 @default.
- W1984583221 cites W2162077816 @default.
- W1984583221 cites W2333318499 @default.
- W1984583221 cites W2340653501 @default.
- W1984583221 cites W2343195578 @default.
- W1984583221 cites W2344056141 @default.
- W1984583221 cites W2526922853 @default.
- W1984583221 cites W2949355120 @default.
- W1984583221 cites W2949521671 @default.
- W1984583221 cites W2949623532 @default.
- W1984583221 cites W2950034109 @default.
- W1984583221 cites W2950642784 @default.
- W1984583221 cites W2951202653 @default.
- W1984583221 cites W2951727426 @default.
- W1984583221 cites W2952033705 @default.
- W1984583221 cites W2952412492 @default.
- W1984583221 cites W2952764251 @default.