Selective Fluorescence Quenching of Alternant vs. Non-Alternant Polycyclic Aromatic Hydrocarbons by Carbon Tetrachloride

Patra, Digambara; Mishra, Ashok Kumar

doi:10.1366/0003702011954080

Cited by 4 publications

(3 citation statements)

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“…The longer fluorescence lifetime of these compounds in THF and 1,4-dioxane can be explained due to the stabilization of the excited-state by the oxygen atom present in these solvents. On the other hand, the relatively short lifetime of the compounds in dichloromethane and 1,2-dichlorobenzene can be attributed to the fluorescence quenching effect by dichloromethane and 1,2-dichlorobenzene, as chlorinated compounds are known to increase the rates of nonradiative processes. , …”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, the relatively short lifetime of the compounds in dichloromethane and 1,2-dichlorobenzene can be attributed to the fluorescence quenching effect by dichloromethane and 1,2-dichlorobenzene, as chlorinated compounds are known to increase the rates of nonradiative processes. 53,54 The fluorescence quantum yield was determined as stated earlier using anthracene in ethanol as a standard reference. The fluorescence quantum yield was, in general, found to be small in THF for all TQPP-[t-Bu] 2 -[XR] 4 molecules under investigation, whereas higher quantum yields were found in cyclohexane and dioxane.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis and Detailed Photophysical Studies of Pyrene-Based Molecules Substituted with Extended Chains

et al. 2009

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Applications of conjugated organic compounds in the field of electronics and optoelectronics and of pyrene derivatives as fluorescent probes are well established. The synthesis of the novel pyrene-based 2,11-di-tert-butyl-6,7,15,16-tetrakis(alkoxy/alkythio)quinoxaline[2',3':9,10]phenanthro[4,5-abc]phenazine, TQPP-[t-Bu](2)-[XR](4) (X = O, S; R = C(n)H(2n+1)), is reported along with an in-depth spectroscopic characterization and evaluation of their photophysical properties. Despite their larger core size, the reported TQPP materials showed similar fluorescence behavior to that of pyrene itself, with no significant shift in their fluorescence peak. The fluorescence spectra showed peaks corresponding to the monomer and to the excimer. Even though these TQPP compounds showed poor solubility in various solvents, their solvatochromism could be investigated in different solvents ranging from polar solvents such as methanol to nonpolar solvents such as cyclohexane; Stokes shifts, fluorescence lifetimes, fluorescence quantum yields, as well as radiative and nonradiative rate constants are determined for four of these TQPP materials in various solvents. Quantum yields were found to be low for these TQPP compounds in solvents such as tetrahydrofuran (THF), whereas they were relatively higher in cyclohexane and dioxane. Monomer to excimer intensity ratio versus gross solvent scale (E(T)30) and orientation polarizabilty (Delta f) were correlated. Although TQPP-[t-Bu](2)-[XR](4) displayed similar fluorescent emission and excitation behavior as that of pyrene, a relatively smaller lifetime was observed for these compounds compared to that of pyrene.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Synthesis and Detailed Photophysical Studies of Pyrene-Based Molecules Substituted with Extended Chains

et al. 2009

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“…Many molecules are being tested for selective quenching of PAHs. An electron acceptor like nitromethane, [60] cetylpyridinium chloride, [66][67][68][69][70] dodecylpyridinium chloride, [71] pyridinium chloride, [72] carbon tetrachloride [73] etc. quenches selectively alternant PAHs rather than nonalternant ones and electron donor like 1,2,4-trimethoxybenzene, [74] aliphatic amines [75,76] etc.…”

Section: Selective Fluorescence Quenching Studymentioning

confidence: 99%