Generation and structure determination of 5,6-bis(methylthio)-4,7-diethylbenzo[1,2,3]trithiole dication MBT(2+)
| Autor: | Ryu Sato, Satoshi Ogawa, Kiyohito Ito, Yasushi Kawai, Takeshi Kimura |
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| Rok vydání: | 2005 |
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| Zdroj: | Heteroatom Chemistry. 16:111-120 |
| ISSN: | 1098-1071 1042-7163 |
| Popis: | 5,6-Bis(methylthio)-4,7-diethylbenzo-[1,2,3]-trithiole [MBT] was oxidized with two equivalents of SbCl5 to produce a dication, MBT(2+)ċ2SbCl, as a stable, dark-brown solid. MBT(2+) was unexpectedly silent for 1H-NMR in CD3CN, whereas it was active for ESR, suggesting that MBT(2+) is a triplet-state dication MBT(2+)-T. Meanwhile, treatment of 5- methylsulfinyl-6-methylthio-4,7-diethylbenzo[1,2,3]- trithiole [MBTMO] with D2SO4 produced MBT(2+), whose 1H-NMR gave no signals, whereas the solution is active for ESR. These results imply that MBT(2+) prepared from MBTMO is a triplet-state dication, and a singlet-state dication, MBT(2+)-S, initially generated by acidification of MBTMO, isomerized to the triplet-state dication, MBT(2+)-T. Since MBT(2+)-T is active for ESR at room temperature, two molecules of MBT(2+)-T should form a spin pair in the solution with a sufficient distance between the two radical centers. The structures of MBT(2+)-S and MBT(2+)-T were optimized with the DFT method at the B3LYP6-31G** level. The total energy difference between them was calculated to be 7.90 kcal/mol; MBT(2+)-T was shown to be more stable than MBT(2+)-S. A treatment of MBTMO with SbCl5 gave a 1:1 complex. The structure of the complex was determined with X-ray crystallography, which showed that the complex is the corresponding sulfonium salt, MBTMOċSbCl5. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:111–222, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20078 |
| Databáze: | OpenAIRE |
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