Pyrazoles. XIII. Lonisation (constants and UV spectra of mono‐and dinitropyrazoles

Janssen, Johann; Kruse, Claudia; Koeners, H. J.; Habraken, Clarisse L.

doi:10.1002/jhet.5570100635

Cited by 28 publications

(17 citation statements)

References 10 publications

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“…In the case of either 3,5-dinitro-or 3,3′,5-trinitro-4,4′bipyrazoles, significant differentiation of two pyrazole sites in the view of acidity (pK a = 14.63 for the parent pyrazole; 9.81 for 3(5)-nitro and 3.14 for 3,5-dinitropyrazoles) 16 provides total selectivity in the formation of singly charged anions. When combined with relatively weak bases, these bipyrazoles act as monobasic acids only, retaining weakly acidic pyrazole (nitropyrazole) group neutral.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…15 This may be relevant to many common types of nitro-functionalized molecules (e.g., polynitroazoles, nitroamines), since accumulation of explosophore nitro groups results in a dramatic increase of the acidity. 16 Such components as hydroxylammonium cations productively contribute to energy release of the salts due to inherently high nitrogen and oxygen contents and high heat of formation. From the perspective of crystal structure, higher energies of ionic lattices, together with extensive hydrogen bonding typically mediating structures of nitrogen-rich salts, are beneficial for higher densities and thermal stabilities of energetic materials.…”

Section: ■ Introductionmentioning

confidence: 99%

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Midway between Energetic Molecular Crystals and High-Density Energetic Salts: Crystal Engineering with Hydrogen Bonded Chains of Polynitro Bipyrazoles

Gospodinov

Domasevitch

Unger

et al. 2020

Crystal Growth & Design

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A new strategy for supramolecular synthesis of energetic salts is reported. It is still a challenge to address packing patterns and crystal morphologies of such materials due to the lack of reliable supramolecular synthons, which are applicable to polynitro substituted species. 3,5-Dinitro-4,4′-bipyrazole (1), 3,3′,5-trinitro-4,4′-bipyrazole (2), and 3,3′,5,5′-tetranitro-4,4′-bipyrazole (3) are excellent functional models that provide a higher degree of control over the structure by manipulating robust self-assembly molecular building blocks of lower dimensionality. A variety of K+, Cs+, and nitrogen-rich salts (e.g., ammonium, aminoguanidinium, hydrazinium, and hydroxylammonium) 4–17, prepared by single deprotonation of NH-acidic 1–3, are based upon polar anionic chains sustained with strong NH···N bonding of conjugate acidic and basic pyrazole/pyrazolate sites. A gradual increase of NH-acidity (dinitropyrazolyl > nitropyrazolyl ≫ pyrazolyl) productively contributes to the strength of NH···N bonds and reliability of such supramolecular synthon. New synthesized energetic materials were fully characterized by NMR (1H, 13C, and 14N) spectroscopy, infrared spectroscopy, differential thermal analysis (DTA), and elemental analysis, and the heats of formation were calculated using the atomization method based on CBS-4 M enthalpies. Several detonation parameters, such as detonation pressure, velocity, and energy, were calculated by using the X-ray densities and the calculated standard molar enthalpies of formation. The sensitivities toward external stimuli were tested according to the BAM standards. In addition, the toxicity toward Vibrio fischeri bacteria of the monopotassium salt 9·H 2 O is reported.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Midway between Energetic Molecular Crystals and High-Density Energetic Salts: Crystal Engineering with Hydrogen Bonded Chains of Polynitro Bipyrazoles

Gospodinov

Domasevitch

Unger

et al. 2020

Crystal Growth & Design

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“…The easy formation of such salts is conditioned by the appreciable acidity of polynitropyrazoles, c.f. pK a = 3.14 for 3,5-dinitropyrazole versus 14.63 for the parent pyrazole (Janssen et al, 1973), while for the crystallization of singly charged hydrogen bipyrazolate derivatives, the weakly polarizing, large Rb + and Cs + cations are important.…”

Section: Structural Commentarymentioning

confidence: 99%

Isostructural rubidium and caesium 4-(3,5-dinitropyrazol-4-yl)-3,5-dinitropyrazolates: crystal engineering with polynitro energetic species

Domasevitch¹,

Ponomarova²

2021

Acta Cryst E

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In the structures of the title salts, poly[[μ4-4-(3,5-dinitropyrazol-4-yl)-3,5-dinitropyrazol-1-ido]rubidium], [Rb(C6HN8O8)] n , (1), and its isostructural caesium analogue [Cs(C6HN8O8) n , (2), two independent cations M1 and M2 (M = Rb, Cs) are situated on a crystallographic twofold axis and on a center of inversion, respectively. Mutual intermolecular hydrogen bonding between the conjugate 3,5-dinitopyrazole NH-donor and 3,5-dinitropyrazole N-acceptor sites of the anions [N...N = 2.785 (2) Å for (1) and 2.832 (3) Å for (2)] governs the self-assembly of the translation-related anions in a predictable fashion. Such one-component modular construction of the organic subtopology supports the utility of the crystal-engineering approach towards designing the structures of polynitro energetic materials. The anionic chains are further linked by multiple ion–dipole interactions involving the 12-coordinate cations bonded to two pyrazole N-atoms [Rb—N = 3.1285 (16), 3.2261 (16) Å; Cs—N = 3.369 (2), 3.401 (2) Å] and all of the eight nitro O-atoms [Rb—O = 2.8543 (15)–3.6985 (16) Å; Cs—O = 3.071 (2)–3.811 (2) Å]. The resulting ionic networks follow the CsCl topological archetype, with either metal or organic ions residing in an environment of eight counter-ions. Weak lone pair–π-hole interactions [pyrazole-N atoms to NO2 groups; N...N = 2.990 (3)–3.198 (3) Å] are also relevant to the packing. The Hirshfeld surfaces and percentage two-dimensional fingerprint plots for (1) and (2) are described.

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“…This is significant given that histone acetylation accounts for 74% of all acetylated lysines in mammalian cells. [ 75 ]…”

Section: Constraint‐based Modeling Can Predict and Interpret Metabolimentioning

confidence: 99%

Nutrient Sensing by Histone Marks: Reading the Metabolic Histone Code Using Tracing, Omics, and Modeling

Campit

Meliki²,

Youngson

et al. 2020

BioEssays

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Several metabolites serve as substrates for histone modifications and communicate changes in the metabolic environment to the epigenome. Technologies such as metabolomics and proteomics have allowed us to reconstruct the interactions between metabolic pathways and histones. These technologies have shed light on how nutrient availability can have a dramatic effect on various histone modifications. This metabolism–epigenome cross talk plays a fundamental role in development, immune function, and diseases like cancer. Yet, major challenges remain in understanding the interactions between cellular metabolism and the epigenome. How the levels and fluxes of various metabolites impact epigenetic marks is still unclear. Discussed herein are recent applications and the potential of systems biology methods such as flux tracing and metabolic modeling to address these challenges and to uncover new metabolic–epigenetic interactions. These systems approaches can ultimately help elucidate how nutrients shape the epigenome of microbes and mammalian cells.

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Pyrazoles. XIII. Lonisation (constants and UV spectra of mono‐and dinitropyrazoles

Cited by 28 publications

References 10 publications

Midway between Energetic Molecular Crystals and High-Density Energetic Salts: Crystal Engineering with Hydrogen Bonded Chains of Polynitro Bipyrazoles

Midway between Energetic Molecular Crystals and High-Density Energetic Salts: Crystal Engineering with Hydrogen Bonded Chains of Polynitro Bipyrazoles

Isostructural rubidium and caesium 4-(3,5-dinitropyrazol-4-yl)-3,5-dinitropyrazolates: crystal engineering with polynitro energetic species

Nutrient Sensing by Histone Marks: Reading the Metabolic Histone Code Using Tracing, Omics, and Modeling

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