Electrochemical oxidation of tetracyclones and tetraphenylthiophene-S-oxide

Tuning of the Electro-Optical Properties of Tetraphenylcyclopentadienone via Substitution of Oxygen with Sterically-Hindered Electron Withdrawing Groups

In this report, the substitution of the oxygen group (=O) of Tetraphenylcyclopentadienone with =CR2 group (R = methyl ester or nitrile) was found to have tuned the electro-optical properties of the molecule. Although both groups are electrons withdrawing in nature, their absorption from UV-vis spectra analysis was observed to have been blue-shifted by methyl ester substitution and red-shifted by nitrile substitution. Interestingly, these substitutions helped to enhance the overall intensity of emission, especially in the context of methyl ester substitution whereby the emission was significantly boosted at higher concentrations due to hypothesized restrictions of intramolecular motions. These observations were explained through detailed descriptions of the electron withdrawing capability and steric properties of the substituents on the basis of density functional theory calculations.

Photochemical and Electrochemical Oxygenation of Thiophenes, Benzo[b]Thiophenes and Dibenzothiophenes; Photochemical and Electrochemical Behaviour of Their Oxygenated Intermediates and Products

The photooxygenation of thiophenes, benzo[ b]thiophenes and dibenzothiophenes is discussed, especially in view of the oxidative removal of these S-containing contaminants from fuels. Furthermore, the photochemistry of the intermediates and the products from these processes is detailed. Finally, an account is given of the electrooxidation of thiophenes and derivatives to the corresponding sulfoxides and sulfones as well as of the electrochemical behaviour of the intermediate thiophene S-oxides.

Thermal oxidation of tetracyclones (2,3,4,5-tetraarylcyclopentadienones)

Tetracyclones are transformed to a mixture of diacylstilbenes and α-pyrones, when they are heated in diphenylether saturated with oxygen.

Cycloaddition of benzo[b]thiophene-S,S-dioxide – a route to substituted dibenzothiophenes and dibenzothiophene S,S-dioxides

Benzo[b]thiophene S,S-dioxide can be transformed by cycloaddition with tetraarylthiophene S-oxides to tetraaryldibenzothiophene S,S-dioxides. An analogous cycloaddition of benzo[b]thiophene S,S-dioxide, albeit at higher temperatures, leads directly to tetraaryldibenzothiophenes.