Transient Photochemistry of Safranin-O

Baumgartner, Charles E.; Richtol, H. H.; Aikens, D. A.

doi:10.1111/j.1751-1097.1981.tb09315.x

Cited by 45 publications

(19 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Generation of a permanent signal by adding RSH, would be a conrmation for eqn (10). 58,59 Thiyl radicals produced in this reaction could initiate the radical polymerization which was in agreement with RT-FTIR results of 2KSR system.…”

Section: Photoinitiation Mechanismsupporting

confidence: 88%

A new safranin based three-component photoinitiating system for high resolution and low shrinkage printed parts via digital light processing

et al. 2019

View full text Add to dashboard Cite

show abstract

Section: Photoinitiation Mechanismsupporting

confidence: 88%

A new safranin based three-component photoinitiating system for high resolution and low shrinkage printed parts via digital light processing

et al. 2019

View full text Add to dashboard Cite

show abstract

“…According to (2), the square of the polymerization rate is proportional to the quantum yield of initiating radicals. Assuming that the active radicals are formed in equal yield than the semireduced form of the dye, the quantum yield of initiating radicals were estimated from the long-lived absorbance measured by laser flash photolysis at 425 nm, assigned to the radical anion of the dye (Saf •− ) [53].…”

Section: Three-component Photoinitiating Systems Involving Onium Saltsmentioning

confidence: 99%

Two- and Three-Component Visible Light Photoinitiating Systems for Radical Polymerization Based on Onium Salts: An Overview of Mechanistic and Laser Flash Photolysis Studies

Gómez

Previtali

Montejano

2012

International Journal of Photoenergy

View full text Add to dashboard Cite

A review of our work on two- and-three component photoinitiator systems is presented. The emphasis is in on visible light polymerization in aqueous media. The systems discussed comprise a synthetic dye as sensitizer and an onium salt as coinitiator, or a dye-amine-onium salt with the amine as coinitiator and the onium salt as an enhancer of the polymerization efficiency. The effect of the composition of the system on the photopolymerization kinetics was analyzed. To this end, the photophysics and photochemistry of the dye under polymerization conditions was explored by means of stationary and time-resolved spectroscopic methods. Different dyes and onium salts were investigated. The action mechanism of the different photoinitiators systems is discussed.

show abstract

“…Phenosafranine and safranine are two related dyes of very similar photophysical properties (12) but the p K of the excited states are different, due to the presence of two extra methyl groups on the ring in the case of safranine. Thus, the triplet state p K a values are 7.5 and 9.2 in the case of safranine (13) while they are 3.2 and 10.1 in the case of phenosafranine. Therefore, the latter exists in the monoprotonated form PSH + , in a much wider pH range, and it can participate in proton transfer processes in the excited state in addition to the typical electron transfer processes.…”

Section: Introductionmentioning

confidence: 97%

Proton and Electron Transfer in the Excited State Quenching of Phenosafranine by Aliphatic Amines†

Broglia¹,

Bertolotti²,

Previtali³

2007

Photochemistry and Photobiology

View full text Add to dashboard Cite

The quenching of the excited singlet and triplet states of phenosafranine by aliphatic amines was investigated in acetonitrile and methanol. The rate constants for the quenching of the excited singlet state depend on the one-electron redox potential of the amine suggesting a charge transfer process. However, for the triplet state, quenching dependence on the redox potential either is opposite to the expectation or there is not dependence at all. Moreover, in MeOH the first-order rate constant for the decay of the triplet state, k(obs) presents a downward curvature as a function of the amine concentration. This behavior was interpreted in terms of the reversible formation of an intermediate excited complex, and from a kinetic analysis the equilibrium constant K(exc) could be extracted. The log K(exc) shows a linear relationship with the pKb of the amine. On the other hand, for the triplet state quenching in acetonitrile k(obs) varies linearly with the amine concentration. Nevertheless, the quenching rate constants correlate satisfactorily with pKb and not with the redox potential. The results were interpreted in terms of a proton transfer quenching, reversible in the case of MeOH and irreversible in MeCN. This was further confirmed by the transient absorption spectra obtained by laser flash photolysis. The transient absorption immediately after the triplet state quenching could be assigned to the unprotonated form of the dye. At later times the spectrum matches the semireduced form of the dye. The overall process corresponds to a one-electron reduction of the dye mediated by the deprotonated triplet state.

show abstract

Transient Photochemistry of Safranin-O

Cited by 45 publications

References 16 publications

A new safranin based three-component photoinitiating system for high resolution and low shrinkage printed parts via digital light processing

A new safranin based three-component photoinitiating system for high resolution and low shrinkage printed parts via digital light processing

Two- and Three-Component Visible Light Photoinitiating Systems for Radical Polymerization Based on Onium Salts: An Overview of Mechanistic and Laser Flash Photolysis Studies

Proton and Electron Transfer in the Excited State Quenching of Phenosafranine by Aliphatic Amines†

Contact Info

Product

Resources

About