Effect of ultrasound on the photolysis of carbon tetrachloride mediated by benzothiazole derivatives. 2-Sulfanylbenzothiazoles

Gáplovský, Anton; Tomá, Štefan; Luche, Jean‐Louis; Jakubı́ková, Bibiana; Gáplovská, Katarína; Mračnová, Renáta

doi:10.1039/b107526h

Cited by 6 publications

(2 citation statements)

References 26 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From the data reported, general trends seem to appear: (i) a monomolecular process, e.g., the photoisomerization of 2-phenylindane-1,3-dione to 3-benzylidenephthalide, is practically unchanged by sonication; (ii) bimolecular reactions undergo significant changes in rates and selectivity as observed in the photodimerization of acenaphthylene, the addition of cyclohexanone to cyclohexene, and the Paterno−Büchi reaction of acetone to ethyl vinyl ether . An explanation can be the homogeneous distribution of the reactive excited states throughout the solution by cavitational microstreaming, known to provide an ideal stirring. , A recent study of the photorearrangement of diphenyl ether could support the idea that cavitation enhances the quenching of some excited states or cleaves intermediate excimers or exciplexes . To explore further the effects of the combined actions of light and acoustic waves, the photoreduction of benzophenone was investigated, and the results are described in this paper.…”

Section: Introductionmentioning

confidence: 98%

Ultrasound Effects on the Photopinacolization of Benzophenone

Gáplovský

Tomá

et al. 2000

J. Org. Chem.

Self Cite

View full text Add to dashboard Cite

Ultrasonic irradiation is able to modify the course of several photochemical reactions, especially bimolecular, proceeding via triplet states. These effects were illustrated in the study of benzophenone photopinacolization in ethanol. The rates and yields increase when sonication is applied simultaneously to UV irradiation. An explanation is based on a 2-fold effect: (i) light-absorbing transient species undergo sonolytic decomposition, making the photoconversion more efficient, and (ii) sonication induces the triplet state quenching, as shown by Stern-Volmer plots from experiments run in the presence of naphthalene, probably due to the easier collisional deactivation processes favored by the homogeneous distribution of the activated species.

show abstract

Section: Introductionmentioning

confidence: 98%

Ultrasound Effects on the Photopinacolization of Benzophenone

Gáplovský

Tomá

et al. 2000

J. Org. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…These are 2-aminobenzothiazole (2ABT), 2-amino-4-methylbenzothiazole (2A4MBT), and 2-amino-6-methylbenzothiazole (2A6MBT) (Figure ). To our knowledge not much work has been done so far on the photophysical and electron-donating properties of benzothiazoles. , Apart from the spectroscopic studies, photophysical properties of these donors have been investigated in the present work to reveal the mechanisms of nonradiative processes involved. The electron-donating nature of the present benzothiazoles was examined in the presence of the well-known electron acceptor 9-cyanoanthracene (9CNA) in media of isotropic solvents, e.g., nonpolar n -heptane (NH), polar protic ethanol (EtOH), and aprotic acetonitrile (ACN).…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation by Laser Flash Photolysis To Reveal the Optical and Electron-Donating Properties of Benzothiazole Derivatives and a Theoretical Approach by Using Time-Dependent Density Functional Theory

et al. 2004

View full text Add to dashboard Cite

The photophysics and electron-donating nature of the three substituted benzothiazoles (BTs) have been studied by electrochemical, steady state, time-resolved spectroscopic techniques. Calculations on isolated molecules in the gas phase as well as solvent environment were performed with use of the density functional theory (DFT) to correlate with the observed polarized spectra. The time-dependent density functional theory (TD-DFT) has been shown to give reasonable singlet and triplet vertical excitation energies for all the BTs studied. The electrochemical measurements demonstrate that the photoinduced electron-transfer (PET) reactions between the donor BT and excited (S 1 ) acceptor 9-cyanoanthracene (9CNA) are energetically favorable from the thermodynamic point of view. Steady state fluorescence and flash photolysis measurements indicate that the PET is involved only in the excited singlet state of 9CNA in the presence of BTs. It is inferred that the triplet state of 9CNA, being formed by the charge recombination mechanism, would not be involved in the electrontransfer (ET) reaction as the free energy of the triplet state of 9CNA appears to be less than the free energy of the ion-pair (products).

show abstract