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Thiophene is considered to be aromatic, although theoretical calculations suggest that the degree of aromaticity is less than that of benzene. The "electron pairs" on sulfur are significantly delocalized in the pi electron system. As a consequence of its aromaticity, thiophene does not exhibit the properties seen for conventional sulfides. For ...
[1] [2] Thieno[2,3-b]thiophene was the first member of the series to be isolated. It was obtained in very low yield upon heating citric acid, a source of a six-carbon linear chain, with P 4 S 10. [3] More efficient syntheses of this and the other two stable thienothiophenes involve cyclization reactions of substituted thiophenes. [1]
Thiophenol is an organosulfur compound with the formula C 6 H 5 SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplest aromatic thiol.The chemical structures of thiophenol and its derivatives are analogous to phenols, where the oxygen atom in the hydroxyl group (-OH) bonded to the aromatic ring in phenol is replaced by a sulfur atom.
Because of their aromatic character, they are non-nucleophilic. The nonbonding electrons on sulfur are delocalized into the π-system. As a consequence, thiophene exhibits few properties expected for a sulfide – thiophene is non-nucleophilic at sulfur and, in fact, is sweet-smelling.
The lowest triplet state of an annulene is, according to Baird's rule, aromatic when it has 4n π-electrons and antiaromatic when the π-electron count is 4n + 2, where n is any positive integer. This trend is opposite to that predicted by Hückel's rule for the ground state , which is usually the lowest singlet state (S 0 ).
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The 3,4-disubstituted thiophene called ethylenedioxythiophene (EDOT) is the precursor to the polymer PEDOT. Regiochemistry is not an issue in since this monomer is symmetrical. PEDOT is found in electrochromic displays, photovoltaics, electroluminescent displays, printed wiring, and sensors. [46]
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