Synthesis of Oxygenated Fused Oligothiophenes with HOF·CH₃CN

For the first time a range of fused oligothiophenes was oxidized with use of the HOF·CH3CN complex by transferring one or more sulfur atoms to sulfonyl groups under very mild conditions. These materials exhibit considerable red-shift absorptions in the UV/visible relative to the parent compounds. Their highly interesting photoluminescence properties and molecular packing in the solid state are also reported.