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Alternating Binaphthyl−Thiophene Copolymers: Synthesis, Spectroscopy, and Photo...

The synthesis and a comprehensive spectroscopic and photophysical study are presented of four alternating binaphthyl−oligothiophene copolymers (DP: 10−15 repeat units) in solution at room and low temperature and in the solid state (thin films). Detailed results are presented on absorption, emission, and triplet−triplet absorption spectra together with all relevant quantum yields (fluorescence, intersystem cross...

Electronic spectral and photophysical properties of some p-phenylenevinylene ol...

A comprehensive photophysical and spectroscopic study of a new class of p-phenylenevinylene oligomers (PPV-trimers) possessing different alkyl and alkyloxy sidechain substituents and different end groups (aldehyde, CC, phenylene and anthracene units) was undertaken in solution at room temperature (293 K), low temperature (77 K) and in thin films. The study comprises absorption, emission and triplet-triplet abso...

Photophysical Studies of α,ω-Dicyano-oligothiophenes NC(C4H2S)nCN (n = 1−6)

The photophysics of six oligothiophenes end-capped with cyano groups (CNαn) was investigated in solution at room and low temperature. The study comprises singlet−singlet and triplet−triplet absorption and emission spectra together with lifetimes and quantum yields for all the radiative and nonradiative processes. From the lifetimes and quantum yields, it was possible to extract the rate constants for all the pr...

β-Carbolines. 2. Rate Constants of Proton Transfer from Multiexponential Decays...

The β-carbolines present a complex problem involving multiple equilibria in the excited state in hydrogen-bonding solvents including water. Three excited state species exist: neutral, cation, and zwitterion. Here we examine the multiple equilibria and excited state kinetics of harmine, using time-resolved and steady state fluorescence techniques. From an analysis of the multiexponential decays, measured at the...

.beta.-Carboline Photosensitizers. 3. Studies on Ground and Excited State Parti...

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

http://dx.doi.org/10.1021/j100007a065

Effective distances of exothermic charge-transfer reactions in the excited state

A study of intermolecular, exothermic charge-transfer interactions is described. A distance dependence on the unimolecular charge-transfer rate constant k,,(R) is observed in viscous solvents where transfer at longer distances than the collisional one can compete with dissociation of an encounter complex. A comparative study of the quenching phenomena, occurring in a family of redox partners of aromatic esters ...

Dependência do tempo de vida da fluorescência do 9-antroato de metilo na presen...