Über organische Schwefelradikale, VIII. Über Phenoxthin ‐Radikalionen

Schmidt, Ulrich; Kabitzke, Karlheinz; Markau, K.

doi:10.1002/cber.19640970227

Cited by 11 publications

(4 citation statements)

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“…Conversion of 5 into 5,5-Dihydro-5-(methylimmo)phenoxathiin Perchlorate (6). An excess of silver perchlorate was added to a stirred solution of 100 mg (0.28 mmol) of 5 in acetonitrile.…”

Section: Methodsmentioning

confidence: 99%

“…Deprotonation of 2 gave phenoxathiin sulfilimine (4a). Reaction of 4a with p-toluenesulfonyl chloride gave the known tosyl derivative, obtainable also by reaction of phenoxathiin with chloramine-T. Methylation of 4a led to the same product obtainable by direct reaction of 1 with methylamine, i.e., 5,5-dihydro-5(methylimino)phenoxathiin perchlorate (6). Reaction of 4a with 1 led to 3a.…”

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confidence: 94%

“…For the most part, also, the cation radical has been made by oxidation of phenoxathiin with concentrated sulfuric acid, in which medium ESR characterization has been carried out. [3][4][5][6] The cation radical has also been made from both phenoxathiin and phenoxathiin 5oxide by reaction with a variety of Lewis acids (AICI3, FeCla, SbCl.5, etc.) in haloalkane solvents for characterization by absorption spectroscopy.…”

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confidence: 99%

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Ion radicals. XXXIV. Preparation of phenoxathiin cation radical perchlorate. Formation and reactions of S-iminophenoxathiin (phenoxathiin sulfilimine)

Mani¹,

Shine²

1975

J. Org. Chem.

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A method of preparing crystalline phenoxathiin cation radical perchlorate (1) by oxidation of phenoxathiin with perchloric acid in benzene-acetic anhydride is reported. Reaction of 1 with ammonia was controlled so as to give either phenoxathiin sulfilimine perchlorate (2) or the dimeric product 5,5-dihydro-5-(5-phenoxathiiniumylimino)phenoxathiin perchlorate (3a). Deprotonation of 2 gave phenoxathiin sulfilimine (4a). Reaction of 4a with p-toluenesulfonyl chloride gave the known tosyl derivative, obtainable also by reaction of phenoxathiin with chloramine-T. Methylation of 4a led to the same product obtainable by direct reaction of 1 with methylamine, i.e., 5,5-dihydro-5(methylimino)phenoxathiin perchlorate (6). Reaction of 4a with 1 led to 3a. Reaction of 4a with thianthrene cation radical perchlorate led, similarly, to 5,5-dihydro-5-(5-thianthreniumylimino)phenoxathiin perchlorate (9).

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“…Conversion of 5 into 5,5-Dihydro-5-(methylimmo)phenoxathiin Perchlorate (6). An excess of silver perchlorate was added to a stirred solution of 100 mg (0.28 mmol) of 5 in acetonitrile.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 94%

mentioning

confidence: 99%

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Ion radicals. XXXIV. Preparation of phenoxathiin cation radical perchlorate. Formation and reactions of S-iminophenoxathiin (phenoxathiin sulfilimine)

Mani¹,

Shine²

1975

J. Org. Chem.

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“…Wizinger's report is not findable in Chemical Abstracts. I came across it some years ago in reading Schmidt's paper on the EPR of phenoxafhiin cation radicals (28). In that paper, too, is found the reference to Hiickel's book (29), wherein the radical ion nature of meriquinones is discussed in detail and the structure of the thianthrene cation radical is again explicitly given.…”

Section: Foundations Of Modem Eprmentioning

confidence: 98%

Epr and the History of the Thianthrene Cation Radical

Shine¹

1998

Foundations of Modern EPR

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This chapter is concerned with one radical species only, the thianthrene cation radical, Th + . I shall recount the history of the discovery of the structure of Th + not only because it illustrates how EPR was used successfully after initial uncertainties and errors, but also because Th + , with its structure known, was able to play an important role later in studies of reactions of aromatic cation radicals with nucleophiles. I shall not go into those studies, however.The use of EPR spectroscopy to elucidate the structure of aromatic cation radicals began blossoming in the mid-to-late 1950s. It is interesting to note that some of the earliest publications on the subject appeared in the Journal of Chemical Physics, illustrating that the quest to apply EPR to radical structures was still mainly in the hands of physical chemists (1). Perhaps the reason for that was that physical chemists had the ability to build their own spectrometers, or perhaps that organic chemists were not yet acquainted with the powerful tool. It was known then that cation radicals could be formed by treating aromatic compounds with Lewis acids, such as antimony pentachloride, or by dissolving them in concentrated sulfuric acid. Possibly the first to report on EPR and this phenomenon were Hirshon, Gardner and Fraenkel (HGF), who found paramagnetic resonance absorptions with a number of compounds, among which were thiophenol, diphenyl disulfide, and thianthrene (2). It had been shown much earlier by Stenhouse (3) that thiophenol, in forming a purple solution in H2SO4, was oxidized to diphenyl disulfide. This behavior was described in careful detail, subsequently, by Fries and Volk (4), who showed that the diphenyl disulfide was next converted into thianthrene. Fries and Volk deduced that the purple color of solutions of thiophenol and diphenyl disulfide in concentrated H 2 S0 4 was, in fact, caused by the thianthrene, the "magnificent purple" color of whose H 2 S0 4 solution had been already reported by Stenhouse (3). HGF were aware of these early works, and surmised, therefore, that the paramagnetic spectra of the thio compounds in H 2 S0 4 were caused by similar species. The paramagnetic spectra themselves were not given and the report ends with "we are attempting to ascertain what molecular species are responsible for the unusual paramagnetic resonance spectra that are observed in the thio compounds". As far as I am aware, nothing further was reported by HGF, however. Wertz and Vivo were shortly, thereafter, the first to report the characteristic five-line EPR spectrum that was to become so familiar later on (5). Wertz and Vivo obtained the five-line spectrum with solutions of thiophenol, diphenyl disulfide, and thianthrene in H 2 S0 4 . Recognizing that this 202 Foundations of Modern EPR Downloaded from www.worldscientific.com by NANYANG TECHNOLOGICAL UNIVERSITY on 10/02/15. For personal use only.

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Radikale und Radikal‐Reaktionen des ein‐ und zweibindigen Schwefels

Schmidt

1964

Angewandte Chemie

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Organische Radikale des einbindigen Schwefels sind bisher in Losung oder Schmelze nicht nachgewiesen worden. Sterische Abschirmung und Resonanzstabilisierung, welche die Stabilitat der Triarylmethyl-, Diphenylstickstofl-und Phenoxyl-Radilcale bedingen, sind ofenbar nicht mehr imstande, organische Radikale des einbindigen Schwefels in solchen Konzentrationen zu stabilisieren, daJ3 sie mit den heutigen physikalischen Methoden noch nachweisbar sind. -Erst 1963 gelang es, Amino-polyschwefel-Radikale (R2N--Sn-Sx ) in Liisung nachzuweiseri sowie Arylschwefel-Radikale (Ar-Sx ) iind das Phenylselen-Radikal bei ca. -180 "C zu isolieren. -Der Radikalzustand des organisch gebiindenen Schwefels la& sich stabilisieren, wenn man die Assoziation der organischen Schwefel-Radikale durch Fixierung des Radikals im Kristallgitter (,,Cystin-Radikal"), durch AbstoJlung zwischen Radikalionen (Sul'nium-Sake) oder durch Einjiieren (Arylschwefel-Radikale) verhindert. I. Einleitung Die Entdeckung aryl-substituierter Kohlenstoff-, Stickstoff-und Sauerstoff-Radikale hat unsere Vorstellungen von der chemischen Bindung maagebend beeinfluat und zusammen mit dem Nachweis kurzlebiger Alkyl-Radikale erst die Basis zur Erorterung radikalischer Reaktionsmechanismen geschaffen. -Obgleich man in der organischen Chemie des Siliciums, Phosphors und Schwefels zahlreiche Reaktionen kennt [ * *], die sicherlich nach einem radikalischen Mechanismus verlaufen, hat man bisher dreibindige Silicium-und Germanium-Radikale, zweibindige Phosphor-und Arsen-Radikale und einbindige Schwefel-und Selen-Radikale noch nicht gefunden. Nach dreibindigen Radikalen hoherer Elemente der 4. Gruppe haben Krause, Schlenk, Gilman und Selwood vergeblich gesucht [ 1 1. k e r e Beweise fur dreibindige Zinnund Blei-Radikale durch Molekulargewichtsniessungen bedurfen der Bestatigung durch die ESR-Spektroskopie [2]. -Einen der Tetraphenylhydrazin-Disso-[*] Radikal-Reaktionen des vier-und sechswertigen Schwefels werden in dieser Arbeit nicht beriicksichtigt. Fur eine Ubersicht iiber diese Reaktionen siehe [16], S . 326.

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Über organische Schwefelradikale, VIII. Über Phenoxthin ‐Radikalionen

Cited by 11 publications

References 5 publications

Ion radicals. XXXIV. Preparation of phenoxathiin cation radical perchlorate. Formation and reactions of S-iminophenoxathiin (phenoxathiin sulfilimine)

Ion radicals. XXXIV. Preparation of phenoxathiin cation radical perchlorate. Formation and reactions of S-iminophenoxathiin (phenoxathiin sulfilimine)

Epr and the History of the Thianthrene Cation Radical

Radikale und Radikal‐Reaktionen des ein‐ und zweibindigen Schwefels

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