Reactivities of bis(2-bromoethyl)selenium dibromide and its related compounds: formation of hypervalent T-shaped coordinated selenium compounds by reaction with pyridine and its derivatives

Miura, Masatsugu; Takanohashi, Yoshinori; Habata, Yoichi; Akabori, Sadatoshi

doi:10.1016/0040-4039(94)88285-1

Cited by 6 publications

(2 citation statements)

References 19 publications

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“…Structures containing the same pyridinium cation were not found in the CSD . However, structures with similar pyridinium cations have been reported, containing short alkyl chains of one carbon atom and a COOH, CH 3 , COH, CONH 2 or CSeH groups. − In these structures, interactions have also been observed between the C–H pyridinium ring atoms and the respective anions, together with additional interactions between the functionalizing groups and the respective anions.…”

Section: Resultsmentioning

confidence: 77%

Nitrile-Functionalized Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids

et al. 2011

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Two series of 1-alkylpyridinium and N-alkyl-N-methylpiperidinium ionic liquids functionalized with a nitrile group at the end of the alkyl chain have been synthesized. Structural modifications include a change of the alkyl spacer length between the nitrile group and the heterocycle of the cationic core, as well as adding methyl or ethyl substituents on different positions of the pyridinium ring. The anions are the bromide and the bis(trifluoromethylsulfonyl)imide ion. All the bis(trifluoromethylsulfonyl)imide salts as well as the bromide salts with a long alkyl spacer were obtained as viscous liquids at room temperature, but some turned out to be supercooled liquids. In addition, pyrrolidinium and piperidinium ionic liquids with two nitrile functions attached to the heterocyclic core have been prepared. The crystal structures of seven pyridinium bis(trifluoromethylsulfonyl)imide salts are reported. Quantum chemical calculations have been performed on model cations and ion pairs with the bis(trifluoromethylsulfonyl)imide anion. A continuum model has been used to take solvation effects into account. These calculations show that the natural partial charge on the nitrogen atom of the nitrile group becomes more negative when the length of the alkyl spacer between the nitrile functional group and the heterocyclic core of the cation is increased. Methyl or methoxy substituents on the pyridinium ring slightly increase the negative charge on the nitrile nitrogen atom due to their electron-donating abilities. The position of the substituent (ortho, meta, or para) has only a very minor effect on the charge of the nitrogen atom. The (15)N NMR spectra of the bis(trifluoromethylsulfonyl)imide ionic liquids were recorded with the nitrogen-15 nucleus at its natural abundance. The chemical shift of the (15)N nucleus of the nitrile nitrogen atom could be correlated with the calculated negative partial charge on the nitrogen atom.

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Section: Resultsmentioning

confidence: 77%

Nitrile-Functionalized Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids

et al. 2011

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“…[16] For instance, Kice and Favstritsky reported that nucleophilic substitution at a sulfur center is at least 10 9 -10 10 times faster than the corresponding nucleophilic substitution at an sp 3 carbon atom. [17] X-ray crystallographic evidence for the isolation of discrete selenium [18] and tellurium [19] "ate" complexes have also been reported. The formation of such intermediates is prevalent in halogen chemistry as well.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Anionic Hypervalent Cyclic Selenenate Esters: Relevance to the Hypervalent Intermediates in Nucleophilic Substitution Reactions at the Selenium(II) Center

Selvakumar

Singh

Goel

et al. 2011

Chemistry A European J

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The synthesis of a diaryl diselenide that contains 2,6-dicarboxylic acid groups, 2,2'-diselanediylbis(5-tert-butylisophthalic acid) (10), is described. Diselenide 10 undergoes intramolecular cyclization in methanol to form a cyclic selenenate ester, 5-tert-butyl-3-oxo-3H-benzo[c][1,2]oxaselenole-7-carboxylic acid (11). The cyclization reaction proceeds more rapidly in the presence of organic bases, such as pyridine, adenine, and 4,4'-bipyridine, to form pyridinium 5-tert-butyl-3-oxo-3H-benzo[c][1,2]oxaselenole-7-carboxylate (14), adeninium 5-tert-butyl-3-oxo-3H-benzo[c][1,2]oxaselenole-7-carboxylate (15), and 4,4'-bipyridiniumbis(5-tert-butyl-3-oxo-3H-benzo[c][1,2]oxaselenole-7-carboxylate) (16), respectively. However, 2,2'-diselanediyldibenzoic acid (22) does not undergo cyclization under similar conditions. Structural studies on cyclic selenenate esters 14-16 revealed that the Se···O (COO(-)) secondary distances (2.170, 2.075, and 2.176 Å) were significantly shorter than the corresponding Se···O distances (2.465, 2.472, and 2.435 Å) observed for the selenenate esters stabilized by the neutral donors (CHO, COOH, and COOEt). (1)H, (13)C, and (77)Se NMR spectroscopy of compounds 11 and 14-16 reveal that the aryl protons of compound 11 and the organic cations of compounds 14-16 exchange between the two carboxylate groups via a hypercoordinate intermediate. The corresponding hypercoordinate intermediate (14b, pyridinium selenuranide) for compound 14 was detected at low temperatures using (77)Se NMR spectroscopy. The presumed hypercoordinate intermediates in the carboxylate-exchange reactions at the selenium(II) center for a set of model reactions were optimized using DFT-B3LYP/6-311+g(d) calculations and their structural features compared with the X-ray structure of anionic selenenate esters 14-16.

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Molecular and crystal structures of N-(β-d-galactopyranosyl)pyridinium bromide and its per-O-acetylated derivative

Dmochowska¹,

Nowacki²,

Wojnowski³

et al. 2001

Carbohydrate Research

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Reactivities of bis(2-bromoethyl)selenium dibromide and its related compounds: formation of hypervalent T-shaped coordinated selenium compounds by reaction with pyridine and its derivatives

Cited by 6 publications

References 19 publications

Nitrile-Functionalized Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids

Nitrile-Functionalized Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids

Synthesis of Anionic Hypervalent Cyclic Selenenate Esters: Relevance to the Hypervalent Intermediates in Nucleophilic Substitution Reactions at the Selenium(II) Center

Molecular and crystal structures of N-(β-d-galactopyranosyl)pyridinium bromide and its per-O-acetylated derivative

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