The trithiocarbonate anion (CS 3 2− ) was generated in situ from CS 2 and KOH in dimethyl sulfoxide by a simple method and used as a novel synthetic equivalent of the S 2− synthon for the synthesis of 2,5-disubstituted thiophenes from 1,3butadiynes. Additionally, this system was employed for the metal-free synthesis of 2-substituted benzo[b]thiophenes from 2haloalkynyl (hetero)arenes. These compounds were obtained from a cheap and readily available sulfur source in moderate to good yields, with good functional group tolerance.

In this work, we report the use of rongalite in PEG-400 as a general, reusable, efficient, inexpensive and environmentally benign reductive system for elemental chalcogens and its use for the...

Transition metal catalysed direct sulfanylations of unreactive C-H bonds have become a unique and straightforward synthetic strategy in late-stage C-S bond formation of relevant complex molecules. Such transformations have represented...

A series of new 2,5-disubstituted selenophene derivatives are described from elemental selenium and 1,3-diynes in superbasic media. The activation of elemental selenium in a KOH/DMSO system allows cyclization with conjugated diynes at room temperature. The cyclization reaction is extended to a broad range of functional groups, for which photophysics were experimentally and theoretically investigated. The selenophene derivatives present absorption maxima in the UV-A region and fluorescence emission in the violet-toblue region. Fluorescence decay profiles were obtained showing a monoexponential decay with fast fluorescence lifetimes (∼0.118 ns), as predicted by the Strickler−Berg relations. In general, in both investigations, no dependence on the solvent polarity on the absorption and emission maxima location was observed. On the other hand, solvents and substituents are shown to play a role in the fluorescence quantum yield values. In addition, a fluorescence selfquenching behavior could be observed, related to a photoinduced electron-transfer mechanism. Theoretical calculations performed at the MP2/ADC(2)/cc-pVDZ level of theory were performed in order to investigate the photophysical features of this series of selenophene derivatives.