- Carbazolyl nitrenium ion: Electron configuration and antiaromaticity assessed by laser flash photolysis, trapping rate constants, product analysis, and computational studies
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(Graph Presented) Laser flash photolysis of 1-(carbazol-9-yl)-2,4,6- trimethylpyridinium tetrafluoroborate generates the carbazolyl nitrenium ion (τ = 333 ns, kobs = 3.0 × 106 M -1S-1) having absorption bands at 570 and 620 nm in CH3CN. The nitrenium ion is found to have reactivity comparable to structurally similar closed-shell diarylnitrenium ions, but spectroscopic evidence favors an open-shell singlet diradical assignment for the observed nitrenium ion. The carbazolyl nitrenium ion is also more reactive than diarylnitrenium ions as a likely result of antiaromatic character. Ab initio and hybrid DFT calculations were performed to address the degree of antiaromaticity in this and similar nitrenium ions through analysis of optimized geometries, nucleus independent chemical shifts, and isodesmic reactions.
- Winter, Arthur H.,Gibson, Harry H.,Falvey, Daniel E.
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p. 8186 - 8195
(2008/02/13)
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- Synthesis of carbazoles from N-(N,N-diarylamino)phthalimides with aluminum chloride via diarylnitrenium ions
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Generation of diarylnitrenium ions from N-(N,N-diarylamino)phthalimides by treatment with AlCl3 in benzene or in 1,2-dichloroethane leads to formation of carbazoles by intramolecular C-C bond formation. The reaction proceeds in synthetically useful yields.
- Kikugawa,Aoki,Sakamoto
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p. 8612 - 8615
(2007/10/03)
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- Acid-Catalyzed Intermolecular Rearrangement of N-Chlorocarbazole
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The chlorination of carbazole with sodium hypochlorite in CH2Cl2, CHCl3, or CCl4 gave N-chlorocarbazole in 63-95percent yield.It rearranged in refluxing methanol to give carbazole, 3-chlorocarbazole, 1-chlorocarbazole, 3,6-dichlorocarbazole, and 1,6-dichlorocarbazole.These chlorocarbazoles were formed in an acid-catalyzed intermolecular reaction.In the presence of potassium carbonate dechlorination of N-chlorocarbazole was observed.No evidence for an intramolecular rearrangement was found.
- Rosa, Michael De,Quesada, Andres P.,Dodsworth, David J.
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p. 173 - 175
(2007/10/02)
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- PHOTOCHEMICAL REACTION OF CARBAZOLE AND SOME DERIVATIVES IN DICHLOROMETHANE
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By irradiation of carbazole and some derivatives in CH2Cl2 soln two different reaction pathways were observed depending on the substitution of the heterocyclic compound.
- Balsells, R. Erra,Frasca, A. R.
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p. 5363 - 5366
(2007/10/02)
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