Dye Sensitised Photopolymerisation

Timpe, H.‐J.; Jockusch, S.; Körner, K.

doi:10.1007/978-94-011-1876-7_13

Cited by 27 publications

(22 citation statements)

References 73 publications

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“…Furthermore, absorptions characteristic of redox intermediates of either reaction partner were not observed. Importantly, after a certain time, the absorption of ground-state PS + is regenerated by a first-order process corresponding to a triplet lifetime τ 3 ) 25 µs, quite similar to the previously reported value. 13 k q BP ) 5.5 × 10 9 M -1 s -1 , the rate constant of the reaction 3 BP * + PS + , was obtained by a pseudo-first-order kinetic treatment of the changes in the absorption of 3 BP * at 320 nm (Figure 2).…”

Section: Reaction Of Ketonesupporting

confidence: 89%

“…Actually, flash photolysis of acetonitrile solutions containing both PS + and MK at λ ex ) 347 nm revealed that 3 (MK) * reacts with PS + via electron transfer (eq 1b) and not via energy transfer (eq 1a). Evidently, 3 (MK) * reacts with PS + much faster than 3 (BP) * . A rather high rate constant (k q (MK) ) 1.3 × 10 10 M -1 s -1 ), typical for electron transfer, was found by pseudo-first-order kinetic treatment of the ground-state bleaching of PS + at λ obs ) 520 nm, which follows synchronously the decay of the weak T-T absorption of MK at 650 nm.…”

Section: (Psmentioning

confidence: 97%

“…Therefore, the 555-nm band is attributed to "delayed fluorescence" emitted from 1 (PS + ) * , the excited singlet state of PS + . Generally, three different mechanisms can be discussed regarding the origin of the delayed fluorescence in this case: Accordingly, 1 (PS + ) * can be generated by homotriplet-triplet annihilation involving 3 (PS + ) * (eq 2), by triplet-to-singlet energy transfer from 3 (BP) * to PS + (eq 3), and by heterotriplet-triplet annihilation involving 3 (BP) * and 3 (PS + ) * (eq 4). Provided the …”

Section: Reaction Of Ketonementioning

confidence: 99%

“…The slightly higher rate constant measured in the case of ATX indicates a contribution of electron transfer. Notably, 3 ATX * reacts with PS + exclusively via electron transfer in propylene carbonate (PC), a solvent more polar than acetonitrile ( PC ) 65 18 ). The rate constant k e ATX ) 1.4 × 10 9 M -1 s -1 measured in PC is lower than k e MK and k e ABP measured in acetonitrile because of the higher viscosity of this solvent (η PC ) 2.53 cP 19 ; η acetonitrile ) 0.36 cP 17 ).…”

Section: Other Ketonesmentioning

confidence: 99%

“…[1][2][3] In many of these applications, the electronically excited triplet state of the dye is of particular importance. Mostly, however, the quantum yield of triplet formation is rather low, and therefore, triplet sensitizers are employed.…”

Section: Introductionmentioning

confidence: 99%

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Photoinduced Energy and Electron Transfer between Ketone Triplets and Organic Dyes

et al. 1997

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Cationic organic dyes (phenosafranine, safranine T (ST + ), thiopyronine, and methylene blue) are efficient quenchers of the triplet states of aromatic ketones. The triplets of benzophenone (BP), xanthone, thioxanthone, benzil, and N-methylacridone are quenched by the dyes via energy transfer, generating triplet excited dyes (typically k q ) 5.5 × 10 9 M -1 s -1 for 3 BP * + ST + in acetonitrile solution). Regarding Michler's ketone, p-(dimethylamino)benzophenone, and 3,6-bis(dimethylamino)thioxanthone, the mechanism of triplet quenching is solvent-dependent. Electron transfer occurs in polar solvents like acetonitrile, and energy transfer is the dominant reaction pathway in less polar solvents, such as dichloromethane. Delayed fluorescence of the dye caused by heterotriplet-triplet annihilation involving ketone and dye was detected upon studying the reaction of the dyes with triplet excited ketones (BP, xanthone, thioxanthone, and benzil). By applying two successive laser pulses (λ ex ) 532 and 308 nm, respectively), the rate constant of the reaction 3 BP * + 3 (ST + ) * was determined: k ht ) 1.1 × 10 10 M -1 s -1 .

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Section: Reaction Of Ketonesupporting

confidence: 89%

Section: (Psmentioning

confidence: 97%

Section: Reaction Of Ketonementioning

confidence: 99%

Section: Other Ketonesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Photoinduced Energy and Electron Transfer between Ketone Triplets and Organic Dyes

et al. 1997

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A mechanistic investigation of the three-component radical photoinitiator system Eosin Y spirit soluble,N-methyldiethanolamine, and diphenyliodonium chloride

Padon

Scranton

2001

J. Polym. Sci. A Polym. Chem.

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Photopolymerization Reactions Initiated by a Visible Light Photoinitiating System: Dye/Amine/Bis(trichloromethyl)-Substituted-1,3,5-Triazine

Grotzinger

Burget

Jacques

2001

Macromol. Chem. Phys.

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Addition of a bis(trichloromethyl)‐substituted‐1,3,5‐triazine (Tz) to a dye/amine photoinitiating system leads clearly to an increased efficiency of polymerization under visible light irradiation. The polymerization rates obtained with three triazine derivatives with either phenosafranine, eosin or Rose Bengal as light absorbing species, were measured. Whatever the investigated dye/amine mixture, the addition of Tz led to a strong synergistic effect: the inhibition time decreased and the polymerization rate increased significantly when the three components were used jointly. The spectroscopic and redox properties of the Tz were measured. The system dye/amine/Tz was investigated through time‐resolved laser spectroscopy and steady state fluorescence experiments. A detailed reaction mechanism was elaborated which shows that Tz acts mainly as an inhibitor scavenger. The involved inhibitor is the reduced dye (DH∗︁) arising from the first photochemical reaction between the excited states of the dye and the amine.

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Dye Sensitised Photopolymerisation

Cited by 27 publications

References 73 publications

Photoinduced Energy and Electron Transfer between Ketone Triplets and Organic Dyes

Photoinduced Energy and Electron Transfer between Ketone Triplets and Organic Dyes

A mechanistic investigation of the three-component radical photoinitiator system Eosin Y spirit soluble,N-methyldiethanolamine, and diphenyliodonium chloride

Photopolymerization Reactions Initiated by a Visible Light Photoinitiating System: Dye/Amine/Bis(trichloromethyl)-Substituted-1,3,5-Triazine

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