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Comprehensive Investigation of the Photophysical Behavior of Oligopolyfurans
Melo, J. Seixas de; Elisei, Fausto; Gartner, Carlos; Aloisi, Gian Gaetano; Becker, Ralph S.The photophysical properties of (oligo)polyfurans (Fn, where n = 1−5 represents the number of rings) are presented for the first time for 2−4 rings and compared to parallel data for the corresponding (oligo)polythiophenes (Tn). The quantum yields of fluorescence of the polyfurans are consistently considerably greater (5−50-fold), and that of the triplet occupation, considerably smaller (2.5−4) than for the poly...
Comprehensive Evaluation of the Absorption, Photophysical, Energy Transfer, Str...
Becker, Ralph S.; Melo, J. Seixas de; Maçanita, António L.; Elisei, FaustoA large basis set of R-oligothiophenes with two to seven rings (R2-R7), also including thiophene, R1, have been investigated in five solvents regarding absorption, fluorescence and phosphorescence, quantum yields of fluorescence ( F) and triplet formation ( T), lifetimes of fluorescence and the triplet state, quantum yields of singlet oxygen production ( ¢), all rate constants kF, kIC, kISC, and several of the ...
.beta.-Carboline Photosensitizers. 3. Studies on Ground and Excited State Parti...
Varela, A. P.; Miguel, M. da G.; Maçanita, A. L.; Burrows, Hugh D.; Becker, Ralph S.The photophysical behavior of the P-carbolines norharmane, hmane, and harmine has been studied in waterin- oil (w/o) microemulsions in AOT/cyclohexane. With pure solvents, solubility and partitioning studies indicate that these molecules dissolve preferentially in the organic phase but that their solubility in the aqueous phase increases upon decreasing pH as a consequence of protonation. However, in w/o microe...
Comment on Excited-State Acid-Base Kinetics and Equilibria in Norharmane
Varela, A. P.; Dias, A.; Miguel, M. da Graça; Becker, Ralph S.; Maçanita, A. L.http://dx.doi.org/10.1021/j100007a065
Photophysical Behavior of Coumarins as a Function of Substitution and Solvent: ...
Melo, J. Sérgio Seixas de; Becker, Ralph S.; Maçanita, António L.The nature of the lowest excited state for coumarin and some derivatives was investigated using steady-state and time-resolved fluorescence data at room temperature, as well as fluorescence anisotropy at 77 Kin nonpolar and polar solvents in conjunction with theoretical data obtained with different methods: INDO/S-CI, CNDO/ S-CI, MNDO-CI, and AM1-CI. Theresultsshow that SI isactually n,?r* for coumarininanysolv...
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