α-1<i>H</i>-1,2,3,4-Tetrazole

Goddard, Richard; Heinemann, Oliver; Krüger, Christoph

doi:10.1107/s0108270197000772

Cited by 50 publications

(55 citation statements)

References 5 publications

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“…[74] In solution, the more polar 1H-tetrazole tautomer is more favoured by polar solvents, [75,76] and in the solid state, where hydrogen bonding must be considered, only the 1H-tetrazole tautomer is known. [77] Transition states and reaction paths: The transition state structures (Table 5) show lengthening of the N1ÀN5 and N3ÀN4 bonds by about 0.2 ä and shortening of the N4ÀN5 distance by about 0.1 ä, in accordance with a 1,3-dipolar cycloreversion. The N1ÀN5 distance is shorter than the N3ÀN4 distance, and this implies an asymmetric ring opening.…”

Section: Resultsmentioning

confidence: 81%

Azolylpentazoles as High‐Energy Materials: A Computational Study

Hammerl

Klapötke

Schwerdtfeger

2003

Chemistry A European J

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The structures of highly energetic substituted pentazole compounds and their decomposition to give dinitrogen and the corresponding azide were investigated by ab initio quantum chemical methods. The substituents include azolyl groups (five-membered aromatic rings with different numbers of nitrogen atoms), CH(3), CN, and F. The decomposition pathway was followed for several substituted azolyl- and phenylpentazoles and compared to the known experimental and theoretical results. The NMR parameters of most of the as-yet unknown pentazole compounds were predicted. The activation energy for the decomposition increases, while the decomposition energy of the substituted pentazole decreases with greater electron-donating character of the substituent of the pentazole. Thus, anionic pentazoles are more stable than neutral pentazoles. Methylpentazole is predicted to be among the most stable pentazoles, even though it does not contain an aromatic system.

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Section: Resultsmentioning

confidence: 81%

Azolylpentazoles as High‐Energy Materials: A Computational Study

Hammerl

Klapötke

Schwerdtfeger

2003

Chemistry A European J

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] From a fundamental point of view, tetrazoles are also particularly interesting systems, especially because of the tautomerism they may exhibit and their diversified photochemistry. 1,[21][22][23][24][25][26][27][28][29] Unsubstituted tetrazole, for example, was found to exist exclusively in the crystalline phases as the 1H-tautomer, [30][31][32] whereas in solution and gas phase 1H-and 2H-tautomers coexist, the population of the most polar 1H form increasing with the polarity of the solvent. 21,[33][34][35][36][37] According to the experimental findings, 2H-tetrazole was found to be the lowest energy tautomer in media with a dielectric constant smaller than about 7, while in media with a larger dielectric constant, a reversal of energy takes place and 1H-tetrazole becomes the tautomeric ground state.…”

Section: Introductionmentioning

confidence: 99%

Tautomer Selective Photochemistry in 1-(Tetrazol-5-yl)ethanol

et al. 2010

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A combined matrix isolation FTIR and theoretical DFT/B3LYP/6-311++G(d,p) study of the molecular structure and photochemistry of 1-(tetrazol-5-yl)ethanol [1-TE] was performed. The potential energy surface landscapes of the 1H and 2H tautomers of the compound were investigated and the theoretical results were used to help characterize the conformational mixture existing in equilibrium in the gas phase prior to deposition of the matrices, as well as the conformers trapped in the latter. In the gas phase, at room temperature, the compound exists as a mixture of 12 conformers (five of the 1H tautomer and seven of the 2H tautomer). Upon deposition of the compound in an argon matrix at 10 K, only three main forms survive, because the low barriers for conformational isomerization allow extensive conformational cooling during deposition. Deposition of the matrix at 30 K led to further simplification of the conformational mixture with only one conformer of each tautomer of 1-TE surviving. These conformers correspond to the most stable forms of each tautomer, which bear different types of intramolecular H-bonds: 1H-I has an NH · · · O hydrogen bond, whereas 2H-I has an OH · · · N hydrogen bond. Upon irradiating with UV light (λ > 200 nm), a matrix containing both 1H-I and 2H-I forms, an unprecedented tautomer selective photochemistry was observed, with the 2H tautomeric form undergoing unimolecular decomposition to azide + hydroxypropanenitrile and the 1H-tautomer being photostable.

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“…7,8 Besides, tetrazoles also receive application in agriculture, as plant growth regulators, herbicides and fungicides, 9 as stabilizers in photography and photoimaging 10 and as gasgenerating agents for airbags. 11 From a more fundamental point of view, tetrazoles are also particularly interesting molecules, because they have been shown to exhibit tautomerism [12][13][14][15][16][17][18][19][20][21][22][23] and a very rich photochemistry. [24][25][26][27] The parent compound of the tetrazole series, unsubstituted tetrazole, CN 4 H 2 , exhibits tautomerism.…”

Section: Introductionmentioning

confidence: 99%

Molecular Structure, Vibrational Spectra and Photochemistry of 2-Methyl-2H-Tetrazol-5-Amine in Solid Argon

et al. 2005

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In this work, the molecular structure, infrared spectrum and UV photochemistry of 2-methyl-2H-tetrazol-5-amine (2MTA) isolated in solid argon (10 K) were investigated. The experimental studies were supported by extensive DFT(B3LYP)/6-311++G(d,p) calculations. The infrared spectrum of matrix-isolated 2MTA was fully assigned and correlated with structural properties. Taking into consideration the observed frequency of the NH 2 wagging mode, it is suggested that, in the matrixes, the amine group becomes slightly more planar than in the gas phase, due to matrix-packing effects. In situ UV irradiation (λ > 235 nm) of the matrixisolated 2MTA monomer is shown to induce three main primary photochemical processes: (1) tautomerization to mesoionic 3-methyl-1H-tetrazol-3-ium-5-aminide; (2) nitrogen elimination, with production of 1-methyl-1H-diazirene-3-amine; (3) ring cleavage leading to production of methyl azide and cyanamide. Following the primary photoproducts, secondary reactions were observed, leading to spectroscopic observation of methylenimine and isocyanidric acid.

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α-1H-1,2,3,4-Tetrazole

Cited by 50 publications

References 5 publications

Azolylpentazoles as High‐Energy Materials: A Computational Study

Azolylpentazoles as High‐Energy Materials: A Computational Study

Tautomer Selective Photochemistry in 1-(Tetrazol-5-yl)ethanol

Molecular Structure, Vibrational Spectra and Photochemistry of 2-Methyl-2H-Tetrazol-5-Amine in Solid Argon

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