Energetic Tricyclic Polynitropyrazole and Its Salts: Proton-Locking Effect of Guanidium Cations.
Inorg Chem
; 60(11): 8339-8345, 2021 Jun 07.
Article
em En
| MEDLINE
| ID: mdl-34014642
ABSTRACT
An axisymmetric polynitro-pyrazole molecule, 3,5-di(3,5-dinitropyrazol-4-yl)]-4-nitro-1H-pyrazole (5), and its salts (6-12) were prepared and fully characterized. These compounds not only show promising energetic properties but also show a unique tautomeric switch via combining different cations with the axisymmetric compound (5). Its salts (6-9) remain axisymmetric when the cations are potassium, ammonium, or amino-1,2,4-triazolium. However, when the cations are guanidiums, the salts (10-12) dramatically become asymmetric owing to the fixed proton. The introduction of guanidium cations breaks the tautomeric equilibrium by blocking the prototropic transformations and results in the switch-off effect to tautomerism. The structural constraints of 1H NMR and 13C NMR spectra provide strong evidence for the unusual structural constraint phenomenon. These stabilized asymmetric tautomers are very important from the point of molecular recognition, and this research may promote further developments in synthetic and isolation methodologies for novel bioactive pyrazole-based compounds.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article