1937-19-5Relevant articles and documents
Green Energetic Nitrogen-Rich Salts of 1,1′-Dinitramino-5,5′-bistetrazolate
He, Piao,Wu, Le,Wu, Jinting,Wang, Qianyou,Li, Zhimin,Gozin, Michael,Zhang, Jianguo
supporting information, p. 11159 - 11168 (2017/08/22)
A series of nitrogen-rich energetic salts of 1,1′-dinitramino-5,5′-bistetrazolate (DNABT) guanidinium (1), aminoguanidinium (2), diaminoguanidinium (3), triaminoguanidinium (4), diaminouronium (5), 3,4-diamino-1,2,4-triazolium (6), and ethylenediammonium (7) was synthesized by a metathesis strategy and characterized by elemental analysis, mass spectrometry, and IR spectroscopy as well as single-crystal X-ray diffraction and differential scanning calorimetry (DSC). The natural bond orbitals (NBOs) and electrostatic potentials (ESPs) were further computed for a better understanding of the structures of the DNABT molecule. The heats of formation were calculated based on the Born–Haber energy cycle. The detonation parameters were evaluated by using the EXPLO5 program, and the sensitivities were measured according to BAM standers. These new salts exhibit highly positive heats of formation (407.0–1377.9 kJ mol?1) and good thermal stabilities (180–211 °C). Most of these compounds possess detonation velocities comparable to RDX and acceptable detonation pressures. The high volumes of explosion gases of the salts 3 and 4 (921 and 933 L kg?1, respectively) further support their power as explosives. The enhancing performances, the fact of being free of metals, and the more moderate sensitivities than K2DNABT, suggest that the salts 4 (D=8851 m s?1, P=29.0 GPa), 5 (D=9053 m s?1, P=32.3 GPa), and 6 (D=8835 m s?1, P=30.2 GPa) might be potential environmentally friendly energetic materials.
Mechanism of general acid-base catalysis in transesterification of an RNA model phosphodiester studied with strongly basic catalysts
Corona-Martinez, David O.,Taran, Olga,Yatsimirsky, Anatoly K.
supporting information; body text, p. 873 - 880 (2010/06/20)
Using 80% vol aqueous DMSO as the reaction medium for transesterification of an RNA model substrate 2-hydroxypropyl 4-nitrophenyl phosphate allows one to observe catalysis in buffer mixtures composed of highly basic components such as guanidines, amidines or alkylamines, which provide up to 103-fold accelerations over the background reaction in the 0.01-0.1 M concentration range. The rate law kobs = k1[B] + k2[B] [BH+] was established indicating contributions from both simple general base catalysis and the reaction involving concerted action of neutral (B) and protonated (BH+) forms of the buffer. The catalytic efficiency of guanidinium and amidinium cations is 10 times larger than that of more acidic ammonium cations. Rate constants k1 and k2 obey the Bronsted equations with the slopes 0.77 and 0.69 respectively. Proton inventory for k2 (B = guanidine) in D2O/H 2O mixtures gives two fractionation factors φ1 = 0.48 and φ2 = 1.26 for normal and inverse isotope effects respectively. The former results from the proton transfer to B and the latter from the binding of guanidinium cation to the phosphate group as follows from observation of an inverse solvent isotope effect for the binding of guanidinium and amidinium cations to a phosphodiester anion. The results of kinetic studies together with analysis of transition state stabilization free energies for guanidinium and amidinium cations show that the protonated buffer component acts via electrostatic transition state stabilization rather than proton transfer, which may be possible for a guanidinium assisted hydroxide catalyzed reaction. The Royal Society of Chemistry 2010.
Thermodynamic and kinetic aspects of the reaction of aminoguanidine with malonic acid in acidic aqueous solutions
Chernysheva,Chernyshev,Korolenko,Taranushich
experimental part, p. 1813 - 1817 (2009/09/08)
Thermodynamic and kinetic features of the reaction of aminoguanidine with malonic acid in aqueous solutions at pH 0.5-1.3 to give mono-and diguanylhydrazides of malonic acid were examined, and the reaction mechanism was suggested.
