Asymmetric assembly of pyrazole and 1,2,3-triazole with a methylene bridge: regioisomerism and energetic properties

Xiong, Jin; Cai, Jinxiong; Lai, Qi; Yin, Ping; Pang, Siping

doi:10.1039/d2cc02412h

Cited by 22 publications

(18 citation statements)

References 31 publications

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“…The synthesis routes of compounds DMPT are shown in Scheme 3 . Compound 1-(chloromethyl)-3,5-dinitro-1 H -pyrazol-4-amine ( CDPA ) was prepared according to similar procedures in the literature [ 28 ]. The reaction of intermediate CDPA , 5-aminotetrazoles, KOH and KI at 80 °C in acetonitrile for 12 h, subjected to silica gel column chromatography, gave rise to two methylene-bridged isomers 1-((4-amino-3,5-dinitro-1 H -pyrazol-1-yl)methyl)-1 H -tetrazol-5-amine ( DMPT-1 ) and 2-((4-amino-3,5-dinitro-1 H -pyrazol-1-yl)methyl)-2 H -tetrazol-5-amine ( DMPT-2 ).…”

Section: Resultsmentioning

confidence: 99%

N-Functionalization of 5-Aminotetrazoles: Balancing Energetic Performance and Molecular Stability by Introducing ADNP

Xiong

Chang

Cai

et al. 2022

IJMS

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5-aminotetrazole is one of the most marked high-nitrogen tetrazole compounds. However, the structural modification of 5-aminotetrazole with nitro groups often leads to dramatically decreased molecular stability, while the N-bridging functionalization does not efficiently improve the density and performance. In this paper, we report on a straightforward approach for improving the density of 5-aminotetrazole by introducing 4-amino-3,5-dinitropyrazole. The following experimental and calculated properties show that nitropyrazole functionalization competes well with energetic performance and mechanic sensitivity. All compounds were thoroughly characterized using IR and NMR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Two energetic compounds (DMPT-1 and DMPT-2) were further confirmed by implementing single-crystal X-ray diffraction studies. Compound DMPT-1 featured a high crystal density of 1.806 g cm−3, excellent detonation velocity (vD = 8610 m s−1), detonation pressure (P = 30.2 GPa), and impact sensitivity of 30 J.

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Section: Resultsmentioning

confidence: 99%

N-Functionalization of 5-Aminotetrazoles: Balancing Energetic Performance and Molecular Stability by Introducing ADNP

Xiong

Chang

Cai

et al. 2022

IJMS

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“…Therefore, the energy performance of the compounds could be enhanced by introducing modification groups. Among all the five-membered azole rings, the pyrazole ring has more modification sites and better thermal stability compared to the triazole and tetrazole rings. , Thus, the introduction of modification groups on the pyrazole ring can be used to achieve energetic compounds with good stability while taking into account the energy properties.…”

Section: Introductionmentioning

confidence: 99%

Bicyclic High-Energy and Low-Sensitivity Regioisomeric Energetic Compounds Based on Polynitrobenzene and Pyrazoles

Zhang

et al. 2023

Crystal Growth & Design

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With the development of synthetic methodology and crystallography of energetic materials, regiochemistry is becoming popular and vital in the design of versatile energetic compounds as well as in the thorough research on the relationship between structure and property. In this study, two regioisomeric bicyclic energetic compounds based on pyrazole and polynitrobenzene were synthesized simultaneously by a simple synthetic route, and the regioisomers could be purified by a facile approach. It is interesting to note that the ratio of the two compounds changed with temperature. From 80 to 110 °C, the proportion of compound 2 gradually enhanced with the increase in temperature. In addition, the nitramine product of compound 1 was also synthesized. The structural data of compounds 1, 2, and 3 were confirmed by X-ray single-crystal diffraction. The detonation velocities of the new compounds are in the range of 8436–8788 m s–1 and impact sensitivities are between 15 and 27.5 J, of which compounds 2 and 3 not only present superior sensitivities to those of the classical high-energy explosive RDX (7.5 J) but also exhibit comparable detonation velocities to the measured RDX powder (V D = 8796 m s–1), calculated by EXPLO5 as 8788 and 8526 m s–1, respectively. Moreover, compounds 1 and 2 show good thermal stability with decomposition temperatures up to 263 and 287 °C, which is higher than that of RDX (T dec: 204 °C). All of the above information indicates that these compounds are high-energy, low-sensitivity energetic materials featuring prospective applications.

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“…The critical role of positional isomerism is documented in nearly all other areas of the chemical enterprise . For example, in the field of medicine, the isomers maybe have similar pharmacological effects but different potencies or have distinct pharmacological mechanisms of action (Figure A). − Similarly, in the field of energetic materials, previous studies have shown that the arrangement of functional groups in isomers has a significant impact on physicochemical properties, including density, decomposition temperature, sensitivity, and so on. − For example, the isomer 1,5-diamino-2,4,6,8-tetranitronaphthalene (DATNN-1) has a high density, while the isomer 2,7-diamino-1,3,6,8-tetranitronaphthalene (DATNN-2) has high thermostability (Figure B). Therefore, it is very important and meaningful to study the positional isomers, which could help to understand the structure–property relationships and to accelerate the development of new materials.…”

Section: Introductionmentioning

confidence: 99%

Impact of Positional Isomerism on Melting Point and Stability in New Energetic Melt-Castable Materials

et al. 2023

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For an energetic material with a definite composition, the substituent position is the most crucial factor to influence its physicochemical properties. Thus, it is becoming increasingly important to understand the impact of positional isomerism on multidimensional properties differences. Herein, we reported two new potential energetic melt-castable molecules, a pair of positional isomers (4-MMDNP and 5-MMDNP). These two explosives exhibit obviously different properties, including densities (Δρ = 0.03 g cm −3 ), melting point (ΔT m = 47.2 °C), decomposition temperature (ΔT d = 27.3 °C), stability (IS = 20 J, FS = 160 N vs IS = 10 J, FS = 40 N), etc., even though they share similar compositions and structures. Simultaneously, by analyzing crystal packing, intermolecular interactions, and monomolecular parameters, we were able to uncover the roots of property differences. Altogether, our results provide comprehensive molecular and crystal level insight into the effect of positional isomerism, which may be useful for new molecular design.

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Asymmetric assembly of pyrazole and 1,2,3-triazole with a methylene bridge: regioisomerism and energetic properties

Abstract: An asymmetric N-bridged strategy was employed to link two different energetic building blocks. The resulting compounds not only exhibit good crystal density and low sensitivity, but also demonstrate the key...

Cited by 22 publications

References 31 publications

N-Functionalization of 5-Aminotetrazoles: Balancing Energetic Performance and Molecular Stability by Introducing ADNP

N-Functionalization of 5-Aminotetrazoles: Balancing Energetic Performance and Molecular Stability by Introducing ADNP

Bicyclic High-Energy and Low-Sensitivity Regioisomeric Energetic Compounds Based on Polynitrobenzene and Pyrazoles

Impact of Positional Isomerism on Melting Point and Stability in New Energetic Melt-Castable Materials

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