The effect of micellar phase on the state and dynamics of some excited state charge transfer complexes

Katušin-Ražem, Branka; Wong, Maureen; Thomas, J. K.

doi:10.1021/ja00474a007

Cited by 71 publications

(26 citation statements)

References 4 publications

(4 reference statements)

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“…Figure 2 shows the variation of Qlon as a function of the surfactant concentration and the amount of dispersed water in BHDC media. Some representative @, , , values are also reported in Table 1, together with those observed in other media (8)(9)(10).…”

Section: Resultsmentioning

confidence: 69%

“…it is neither first nor second order). For the sake of comparison, the data in Table 1 include the half-life of the Pya-, t,, in BHDC media under several conditions, together with literature values in homogeneous and normal micelles of cetylmethylammonium bromide (CTAB) (10). The decay of the Pya-is -1.5 times faster in BHDC-chlorobenzene than in BHDC-benzene microemulsions, except at R = 0 where t, is almost the same in both solvents.…”

Section: Resultsmentioning

confidence: 99%

“…This is at variance with what happens in reverse micelles where the fast exchange of solutes between water pools also affects the back electron-transfer recombination reaction between Py'+ and DMA". In aqueous solutions of cationic micelles the radical-ion' s back recombination depends on the rate of entrance of the DMA" from the bulk aqueous phase through the cationic micellar surface, which presents a high barrier due to the electrostatic repulsion (9)(10)(11).…”

Section: Decay Of the Py'-and Exchange Of Materials Between Water Poolsmentioning

confidence: 99%

“…On the other hand, in polar solvents the emission of the exciplex is not observed, but radical ions from the electron-transfer quenching of Py are produced with high efficiency (8). The reaction has also been studied in organized media such as micelles (9)(10)(11), liposomes (12), and solid surfaces (13).…”

Section: Introductionmentioning

confidence: 99%

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Photoinduced Charge Separation in Reverse Micelles Prepared with Benzylhexadecyldimethylammonium Chloride (BHDC). The Electron-Transfer Reaction between Pyrene and N,N′-Dimethylaniline

Borsarelli¹,

Cosa²,

Previtali³

1998

Photchem. Photbio.

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Laser flash photolysis was used to investigate the formation of radical ions produced in the quenching of the pyrene-N,N'-dimethylaniline exciplex by reverse micelles made with benzylhexadecyldimethylammonium chloride (BHDC) dispersed in benzene or chlorobenzene. The radical ion quantum yields, aion, were determined as a function of BHDC concentration and the amount of water dispersed. They were strongly dependent on the composition of the media. The charge separation was more effective in the BHDC-benzene than in the BHDC-chlorobenzene system. The results are discussed in terms of the properties of the micellar interface and the fast exchange of material produced by collisions between reverse micelles.

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Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: Decay Of the Py'-and Exchange Of Materials Between Water Poolsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photoinduced Charge Separation in Reverse Micelles Prepared with Benzylhexadecyldimethylammonium Chloride (BHDC). The Electron-Transfer Reaction between Pyrene and N,N′-Dimethylaniline

Borsarelli¹,

Cosa²,

Previtali³

1998

Photchem. Photbio.

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“…Apparently, heavy atom effect is responsible for the negative salt effect of iodide6. The finding that the reactivities of IIb, III, and IV are much higher than that of V while reactivities of I and p-methoxybenzophenone are almost identical suggests that the distance between (7) and acceleration of process (8) and possibly of process (9) 3 Exchange of bromide i on with chloride ion over an i on exchange r(Diaion resin SA-10, Mitsubi-4 Reaction with an excess amount of the bromide in alkaline(aq. NaOH) condition for 8h under reflux.…”

mentioning

confidence: 99%

Unexpected High Photooxidizing Efficieny of Benzophenone Derivatives Having Tetraalkylammonium Substituents

et al. 1980

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Benzophenone derivatives having various tetraalkylammonium ion in the 4 position (II, III, IV, and V) were found to be much more efficient sensitizers than benzophenone(I) in photooxidation of Leuco Crystal Violet(LCV) to Crystal Violet(CV+) in acetonitrile in air, which was interpreted in terms of the cationic atmosphere effect facilitating the primary electron transfer process from LCV to BP*3.In the course of investigating photochemical and photophysical behaviors of molecular aggregates in which benzophenone(BP) molecules are chemically bound, we found that BP derivatives having quarternary ammonium ion(II, III, IV, and V) revealed very much enhanced photosensitivity towards photooxidation of Leuco Crystal Violet(LCV) in acetonitrile2.When dry acetonitrile solution containing LCV(10-4M) and BP derivative(10-3M) is irradiated with a Xenon lamp in the wavelength region between 340 and 420nm, the BP derivative is selectively profile are shown in Figure 1.These differences in reactivity are obviously not attributable to absorption differences of Ordinary substituent effects on aromatic compounds could not explain the results as well, since inductive effect by ammonium ion remotely attached to BP(V) is hardly conceivable. Another approach to interprete the results on the basis of molecular aggregate formation(micellar effect) seems to be not appropriate3. Although molecular association of surfactant molecules in both polar and non-polar organic solvents has been demonstrated4,5, comparable reactivities of IIb and III indicate that surfactant properties of sensitizers are not of importance. A remaining possibility is neutral salt effect. By adding a variety of neutral salts to I, the rate of CV+ formation increases as shown in Figure 2. This positive salt effect is not limited to tetraalkylammonium salts. Lithium chloride is equally effective. Apparently, heavy atom effect is responsible for the negative salt effect of iodide6. The finding that the reactivities of IIb, III, and IV are much higher than that of V while reactivities of I and p-methoxybenzophenone are almost identical suggests that the distance between

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Photoinduced Electron Transfer in Organic Systems: Control of Back Electron Transfer

Fox

1986

Advances in Photochemistry

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The effect of micellar phase on the state and dynamics of some excited state charge transfer complexes

Cited by 71 publications

References 4 publications

Photoinduced Charge Separation in Reverse Micelles Prepared with Benzylhexadecyldimethylammonium Chloride (BHDC). The Electron-Transfer Reaction between Pyrene and N,N′-Dimethylaniline

Photoinduced Charge Separation in Reverse Micelles Prepared with Benzylhexadecyldimethylammonium Chloride (BHDC). The Electron-Transfer Reaction between Pyrene and N,N′-Dimethylaniline

Unexpected High Photooxidizing Efficieny of Benzophenone Derivatives Having Tetraalkylammonium Substituents

Photoinduced Electron Transfer in Organic Systems: Control of Back Electron Transfer

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