1,2,3-Benzodithiazolyl radicals formed by thermolysis and photolysis of 1,3,2,4-benzodithiadiazines

Vlasyuk, Ivan V.; Bagryansky, V. A.; Gritsan, Nina P.; Molin, Yuri N.; Makarov, Alexander Yu.; Gatilov, Yuri V.; Shcherbukhin, Vladimir V.; Zibarev, Andrey V.

doi:10.1039/b008408p

Cited by 35 publications

(39 citation statements)

References 14 publications

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“…8 A similar wavelength dependence was observed at cryogenic temperatures. We were unable to decompose 1 using light in the range of 425-700 nm, whereas a comparable amount of 1 was decomposed on excitation at 365 nm for 2 h and at 313 nm for 5 min although the optical densities of the samples at the excitation wavelengths (313 and 365 nm) were similar (0.9 and 1.2).…”

Section: Resultssupporting

confidence: 72%

Matrix Isolation and Computational Study of the Photochemistry of 1,3,2,4-Benzodithiadiazine

et al. 2007

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Photolysis of 1,3,2,4-benzodithiadiazine (1) at ambient temperature yields stable 1,2,3-benzodithiazolyl radicals. In order to reveal the mechanism of this unusual transformation, the photochemistry of 1 was studied in argon matrices using IR and UV-vis spectroscopy. A series of intermediates, including four-and fivemembered heterocyclic and o-quinoid acyclic species, were characterized spectroscopically with the help of quantum chemical calculations. With selective irradiation, these intermediates can be mutually interconverted as well as converted back to the starting compound 1.

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Section: Resultssupporting

confidence: 72%

Matrix Isolation and Computational Study of the Photochemistry of 1,3,2,4-Benzodithiadiazine

et al. 2007

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“…According to recent estimations of resonance energy, however, the destabilization of D 4h cyclooctatetraene due to the cyclic interaction of the π bonds (i.e., the antiaromaticity) is negligible. [30] Taking these findings into account, along with the fact that only the heterocyclic moieties of the compounds in series 1 are antiaromatic, whereas the carbocyclic moieties are aromatic (and the C4aϪC8a) bond belongs to both moieties at the same time), as well as other available data on these compounds' molecular and electronic structures [1Ϫ4,6Ϫ9,11] and thermal stabilities, [10,12] one can speculate that, in terms of the aromaticity/antiaromaticity concept, [5] 1,3λ 4 δ 2 ,2,4-benzodithiadiazines could reasonably be classified on the whole as conjugated nonaromatic substances.…”

Section: Antiaromaticitymentioning

confidence: 97%

“…At higher temperatures and in dilute hydrocarbon solutions, compounds 1 quantitatively yield persistent 1,2,3-benzodithiazolyl radicals (Scheme 1), [10,12] which are also the products of photolysis reactions of 1. [10,13] The key intermediates are singlet 1,2,3-benzodithiazol-2-ylnitrenes (Scheme 1), identified under matrix isolation conditions. [13] The other aspects of the heteroatom reactivity of 1 have been studied only to a limited extent.…”

Section: Introductionmentioning

confidence: 99%

Fluorinated 1,3λ⁴δ²,2,4‐Benzodithiadiazines − A Synthetic, Structural and Theoretical Study

et al. 2002

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The series of title compounds has been prepared through both electrophilic (C6HnF5−n−N=S=N−SiMe3 + SCl2) and nucleophilic (C6HF4−S−N=S=N−SiMe3 + CsF) intramolecular ortho‐cyclisation reactions, and the former route seems to be the more effective. High regioselectivity of the ring‐closing procedures is observed in both cases. The compounds were characterised by X‐ray crystallography and multinuclear (1H, 13C, 15N and 19F) NMR spectroscopy. In accordance with GIAO calculations, 15N{1H} experiments and the effects observed on complete substitution of hydrogen by fluorine, the high‐field signal in the 15N NMR spectra can be assigned to N‐4 and the low‐field signal to N‐2. In the crystal, 5,6,7‐trifluoro‐ (5) and 5,6,8‐trifluoro‐1,3λ4δ2,2,4‐benzodithiadiazine (6) are planar, whereas the 6,8‐difluoro derivative 3 is bent along the S1···N4 line by 8.3°. According to NICS calculations the heterocycle moiety in this compound class is antiaromatic while the carbocycle is aromatic. The fluorine substituents increase the aromaticity − and in some cases (especially when a fluorine atom is present in the 8‐position) the antiaromaticity − of the corresponding rings. The ortho‐fluoro‐containing starting material C6HnF5−n−N=S=N−SiMe3 (n = 2: 10) cyclises to the fluorinated 2,1,3‐benzothiadiazole 27 upon treatment with CsF instead of SCl2. For starting compound 6‐HC6F4−S−N=S=N−SiMe3 (14) the planar (Z,E) configuration features a short intramolecular H···N contact, as evidenced by X‐ray diffraction. Both the reaction pathways mentioned are also discussed. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)

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“…It should be emphasized that the thermolysis of 1,3λ 4 δ 2 ,2,4-benzodithiadiazines affords 1,2,3-benzodithiazolyls for which the corresponding 1,2,3-benzodithiazoliums, for example fluoro-containing ones, are unknown. [8,9] With dilute solutions of 1,3λ 4 δ 2 ,2,4-benzodithiadiazines, the yields of radicals estimated by means of ESR measurements are nearly quantitative. It is therefore of obvious interest to investigate whether the thermolysis of 1,3λ 4 δ 2 ,2,4-benzodithiadiazines can be a preparative approach to 1,2,3-benzodithiazolyls.…”

Section: Introductionmentioning

confidence: 98%

“…[8][9][10][11] Mild thermolysis [8,9,11] or photolysis [10,11] of their dilute (10 -3 ) hydrocarbon solutions results in persistent 1,2,3-benzodithiazolyls (Scheme 1), which are promising building blocks in the design and synthesis of organic molecular magnets and/ or organic molecular conductors. [12,13] The key intermediates of this transformation are R-S-N: ↔ R-SϵN nitrenoids (R = 1,2,3-benzodithiazol-2-yl), which can be identified under matrix isolation conditions.…”

Section: Introductionmentioning

confidence: 99%

New Polysulfur‐Nitrogen Heterocycles by Thermolysis of 1,3λ⁴δ²,2,4‐Benzodithiadiazines in the Hydrocarbon and Fluorocarbon Series

et al. 2005

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In contrast to thermolysis of 1,3λ4δ2,2,4‐benzodithiadiazine (1) and its 5,6,7,8‐tetrafluoro derivative 2 in dilute (10–3 M) hydrocarbon solutions, which leads to persistent 1,2,3‐benzodithiazolyls in nearly quantitative yields, the thermolysis of 1 and 2 (the 6‐6 bicyclic system) in concentrated (0.5 M) solutions at 150–170 °C results in complex mixtures of various polysulfur‐nitrogen heterocycles, in particular differently fused 5‐5‐6, 5‐6‐7 and 5‐6‐6‐6 polycyclic systems that were previously unknown. The products were isolated by column chromatography, and the structures of the 5‐5‐6 (11, 12), 5‐6‐7 (5, 13), and 5‐6‐6‐6 (6, 14, 15) polycyclic systems, as well as the 6‐7 (4) and 5‐6 (16) bicyclic derivatives, confirmed by X‐ray diffraction. The crystal packing of 6 and 11–16 is discussed with special emphasis on π‐stacking interactions. The fluorescent properties of the 5‐6‐6‐6 systems synthesized are reported. An alternative approach to the linear 5‐6‐6‐6 system 15 based on self‐condensation of an R–N=PPh3 precursor (R = 4,5,6,7‐tetrafluoro‐1,2,3‐benzodithiazol‐2‐yl) is described, and the free‐radical character of this new reaction is proved. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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1,2,3-Benzodithiazolyl radicals formed by thermolysis and photolysis of 1,3,2,4-benzodithiadiazines

Cited by 35 publications

References 14 publications

Matrix Isolation and Computational Study of the Photochemistry of 1,3,2,4-Benzodithiadiazine

Matrix Isolation and Computational Study of the Photochemistry of 1,3,2,4-Benzodithiadiazine

Fluorinated 1,3λ⁴δ²,2,4‐Benzodithiadiazines − A Synthetic, Structural and Theoretical Study

New Polysulfur‐Nitrogen Heterocycles by Thermolysis of 1,3λ⁴δ²,2,4‐Benzodithiadiazines in the Hydrocarbon and Fluorocarbon Series

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1,2,3-Benzodithiazolyl radicals formed by thermolysis and photolysis of 1,3,2,4-benzodithiadiazines

Cited by 35 publications

References 14 publications

Matrix Isolation and Computational Study of the Photochemistry of 1,3,2,4-Benzodithiadiazine

Matrix Isolation and Computational Study of the Photochemistry of 1,3,2,4-Benzodithiadiazine

Fluorinated 1,3λ4δ2,2,4‐Benzodithiadiazines − A Synthetic, Structural and Theoretical Study

New Polysulfur‐Nitrogen Heterocycles by Thermolysis of 1,3λ4δ2,2,4‐Benzodithiadiazines in the Hydrocarbon and Fluorocarbon Series

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Fluorinated 1,3λ⁴δ²,2,4‐Benzodithiadiazines − A Synthetic, Structural and Theoretical Study

New Polysulfur‐Nitrogen Heterocycles by Thermolysis of 1,3λ⁴δ²,2,4‐Benzodithiadiazines in the Hydrocarbon and Fluorocarbon Series