A facile synthesis of energetic salts based on fully nitroamino-functionalized [1,2,4]triazolo[4,3-b] [1,2,4]triazole

Article abstract of DOI:10.1039/c9dt03829a

A novel family of fully nitroamino-functionalized [1,2,4]triazolo[4,3-b][1,2,4]triazole-based energetic salts were synthesized. All salts were characterized by IR and multinuclear NMR spectroscopy, thermal analysis and elemental analysis. The crystal structures of salts 5, 6, and 7 were confirmed by single-crystal X-ray diffraction. The densities of these salts are between 1.65 (4) and 1.89 g cm^-3 (3), whilst their oxygen balances are between -42.8% (7) and -11.3% (3). Theoretical performance calculations (Gaussian 09 and EXPLO 6.01) provided detonation pressures and velocities for salts 2-7 in the ranges of 27.6-41.1 GPa and 8519-9518 m s^-1, respectively, which make them competitive energetic materials.

Full text of DOI:10.1039/c9dt03829a

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A facile synthesis of energetic salts based on fully
nitroamino-functionalized [1,2,4]triazolo[4,3-
b][1,2,4]triazole†
Cite this: Dalton Trans., 2020, 49,
368
a
Chengming Bian, *a Wenjing Feng,a Qunying Lei,a Haifeng Huang, *b Xia Li,
Jianlong Wang,a Chuan Lic and Zhongliang Xiao*d
A novel family of fully nitroamino-functionalized [1,2,4]triazolo[4,3-b][1,2,4]triazole-based energetic salts
were synthesized. All salts were characterized by IR and multinuclear NMR spectroscopy, thermal analysis
and elemental analysis. The crystal structures of salts 5, 6, and 7 were confirmed by single-crystal X-ray
diffraction. The densities of these salts are between 1.65 (4) and 1.89 g cm−3 (3), whilst their oxygen bal-
ances are between −42.8% (7) and −11.3% (3). Theoretical performance calculations (Gaussian 09 and
EXPLO 6.01) provided detonation pressures and velocities for salts 2–7 in the ranges of 27.6–41.1 GPa
and 8519–9518 m s−1, respectively, which make them competitive energetic materials.
Received 27th September 2019,
Accepted 3rd December 2019
DOI: 10.1039/c9dt03829a
rsc.li/dalton
[4,3-b][1,2,4]triazole.9 Notably, the latter series focused on the
cation of the [1,2,4]triazolo[4,3-b][1,2,4]triazole backbone, but
Introduction
Nitrogen-rich fused heterocyclic compounds have recently the anion has seldom been investigated. Above all, these
been the focus of interest in the study of energetic materials.1 reported energetic materials based on [1,2,4]triazolo[4,3-b]
In addition to the benefits of high nitrogen and low carbon [1,2,4]triazole show poor oxygen balances, which are supposed
contents,2 these compounds possess high heats of formation, to be improved for achieving higher detonation performance.
considerable ring-strain energy, and enhanced densities result-
This study focused on fully nitro- and nitroamino-functio-
ing from the rigid fused-heterocycle coplanar backbone.3 All of nalized [1,2,4]triazolo[4,3-b][1,2,4]triazole with high oxygen
these factors contribute to their enhanced detonation perform- balances of 0% and −8.3%, respectively. Unfortunately, due to
ance and have led to the development of new high-energy- the poor solubility of 3,6,7-triamino-7H-[1,2,4]triazolo[4,3-b]
density materials (HEDMs).4 For example, 4,7-diamine-3,8- [1,2,4]triazole (TATOT)10 in H2SO4/H2O2 and other oxidation
dinitropyrazolo[5,1-c][1,2,4]triazine5 is superior to triaminotri- systems, the attempts to synthesize 3,6,7-trinitro-7H-[1,2,4]tria-
nitrobenzene (TATB) due to its thermal stability, low impact zolo[4,3-b][1,2,4]triazole proved unsuccessful. Therefore,
a
and friction sensitivities, and high density. Shreeve et al. have series of 3,6,7-trinitroimino-7H-[1,2,4]triazolo[4,3-b][1,2,4]tria-
recently reported energetic materials based on fused zolate salts were studied as potential energetic anions. The
triazole that exhibited good to excellent detonation perform-
ance, including 4-amino-3,7-dinitrotriazolo[5,1-c][1,2,4]triazine
(TTX),6 and the salts of 3,6-dinitramino-[1,2,4]triazolo[4,3-b]
[1,2,4,5]tetrazine,7 7-nitro-4-oxo-4,8-dihydro-[1,2,4]triazolo[5,1-
d][1,2,3,5]tetrazine 2-oxide,8 and 3,7-diamino-7H-[1,2,4]triazolo
aSchool of Science, North University of China, Taiyuan, Shanxi, 030051, P. R. China.
E-mail: biancm@nuc.edu.cn
bCAS Key Laboratory of Energy Regulation Materials, Shanghai Institute of Organic
Chemistry, Chinese Academy of Sciences, Ling Road 345, Shanghai, 200032,
P. R. China. E-mail: hfhuang@sioc.ac.cn
cSchool of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng,
252059, P. R. China
dSchool of Chemical Engineering, Nanjing University of Science and Technology,
Nanjing, Jiangsu, 210094, P. R. China. E-mail: xiaozhl2019@163.com
†Electronic supplementary information (ESI) available. CCDC 1947615–1947617.
For ESI and crystallographic data in CIF or other electronic format see DOI:
10.1039/C9DT03829A
Scheme 1 Fused-triazole energetic materials.
368 | Dalton Trans., 2020, 49, 368–374
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salts were fully characterized and their detonation properties fused-triazole backbone. The NMR chemical shifts of the
were calculated. Furthermore, the crystal structures of salts cations in this study are consistent with those of the previously
5·H2O, 6·0.72H2O and 7 were determined using single-crystal published ones.11
X-ray diffraction (Scheme 1).
Crystal structures
Yellow crystals of 5·H2O, 6·0.72H2O and 7, suitable for single-
Results and discussion
Synthesis
crystal X-ray analysis, were obtained by the slow evaporation of
water from the corresponding aqueous solution at room
temperature.
Due to the decomposition of TATOT in nitration systems,
3,6,7-trinitro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazole should be
synthesized at low temperature. As shown in Scheme 2, the
Compound 5·H2O crystallizes in the monoclinic space
group P1 with a calculated density of 1.725 g cm−3. The unit
ˉ
contains two fused-triazole anions, four guanidinium cations
starting material TATOT was dissolved in concentrated sulfuric
and two H2O molecules (Fig. 1). Crystallographic data and
acid/fuming nitric acid below −10 °C and stirred for 4 h at
refinement details are given in the ESI.†
−5 °C. The reaction mixture was quenched with crushed ice,
As shown in Fig. 1a, the deprotonation of the two –NHNO2
filtered and dried over CaCl2 to produce precursor 1.
groups at C3/4 and N20/19 is confirmed. Furthermore, the
tautomerism of the third nitroamine group with the single
hydrogen atom bonded at the C1/6 position produces two
intramolecular hydrogen bonds. These are represented in the
Direct reactions of compound 1 with two equivalents of
ammonia, hydroxylamine and hydrazine resulted in the for-
mation of salts 2, 3 and 4, respectively. The treatment of com-
pound 1 with bisguanidinium carbonate and aminoguanidine
form of two six-membered rings formed by the close proximity
bicarbonate resulted in the formation of salts 5 and 6, respect-
ively. Salt 7 was prepared by adding compound 1 to the
aqueous solution obtained by mixing two equivalents of
sodium hydroxide and 1,3-diaminoguanidine hydrochloride.
All of the energetic salts are soluble in hot water and stable in
air and could be stored for extended periods of time.
Spectroscopy
The chemical shifts in the 13C NMR spectra of compound 1
are identified at 156.63, 144.61 and 143.00 ppm, and the shifts
for its anionic form are in the 141.79 to 159.22 ppm range.
Due to the tautomerism of three protons in nitroamine moi-
eties, the 1H NMR spectrum of compound 1 shows a single
broad peak at 7.50 ppm. The peak at 13.82 ppm in the 1H
NMR spectra of the energetic salts is attributed to NH in the
Fig. 1 (a) Crystal structure of compound 5·H2O. The hydrogen atoms
are included but unlabeled for clarity. (b) Layer-by-layer structure in
5·H2O viewed along the c axis. The guanidinium cations and H2O mole-
Scheme 2 Preparation of 1 and its energetic salts.
cules are omitted for clarity.
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of N3–H3⋯O1 (2.104(1) Å) and N13–H13⋯O7 (2.087(1) Å),
respectively. The lengths of the C–N and N–N bonds connect-
ing the nitroamine groups to triazole range from 1.353(2) Å
(C6–N12) to 1.403(17) Å (N19–N21). This confirms that they lie
between the corresponding single and double bonds and indi-
cates the strong conjugation of the negative charge throughout
the aromatic rings. Most atoms of each anion are roughly
coplanar, with the exception of the nitro group in the nitro-
amine moiety at N19/N20. The largest torsion angle is
110.63(16)°, located among C5–N19–N21–N22. The dihedral
angles between the fused triazole backbone and the three
nitro groups are 5.13° (located at C1), 10.03° (C3) and 77.18°
(N20), respectively. The nitro groups are twisted out of the tri-
azole plane, similar to those of N–NHNO2-functionalized
compounds.4a,12 All the guanidinium cations are roughly
coplanar with the corresponding fused-triazole backbones,
with the largest dihedral angle of 12.39°.
As depicted along the c axis in Fig. 1b, the packing structure
of 5·H2O was built up and linked to a 2D double layer. The dis-
tances between the adjacent layers are 2.977 Å and 3.216 Å.
These distances are much shorter than the typical geometrical
parameters of aromatic π–π interactions (3.65–4.00 Å),13
suggesting strong π–π interactions in combination with hydro-
gen bonds which resulted in closer packing.
Compound 6·0.72H2O crystallizes in the monoclinic space
group P21/c with a calculated density of 1.716 g cm−3. The unit
cell contains one fused-triazole anion, two aminoguanidinium
cations and a disordered H2O molecule. With the exception of
the nitro group (O1–N1–O2), most atoms in the anion are
coplanar. The length of the intramolecular hydrogen bond
between N3–H3⋯O2 is 2.096(2) Å, while the lengths of the C–
N and N–N bonds that combine the nitroamine groups in tri-
azole are 1.348(3) Å, 1.365(3) Å and 1.412(3) Å, respectively.
The two nitro groups of the nitroamine moieties at the C1 and
C3 positions are nearly coplanar with the triazole ring, with di-
hedral angles of 0.58° and 5.17°, respectively. Notably, the
nitro group at N5 is nearly vertical to the fused-triazole plane,
with the largest dihedral angle (87.45°) among those of the
three confirmed analogous guanidine salts. The dihedral
angles between the triazole ring and the two aminoguanidi-
Fig. 2 (a) Crystal structure of compound 6·0.72H2O. (b) Packing
diagram of 6·0.72H2O viewed towards the planes h, k, and l = 0, 0, and
1. The aminoguanidinium cations and H2O molecules are omitted for
clarity.
neighbouring anions (67.73°) in the same layer is slightly
larger than that of salt 6·0.72H2O (61.92°).
Physical and computational properties
nium cations are 11.50° and 62.68°, respectively. As seen in Thermal stability is a key property to evaluate the application
Fig. 2b, 6·0.72H2O shows a wave-like stacking. Due to the per- potential of energetic materials. These new compounds 1–7
pendicular nitro group at N5 and the unparallel cations, the were examined using differential scanning calorimetry (DSC)
layer distance expanded to 3.153 Å and led to the lowest at a heating rate of 5 °C min−1. All decomposed violently
density (1.71 g cm−3) of the three single-crystal molecules.
without melting, with the exception of 2. Salt formation is
Compound 7 crystallizes in the monoclinic space group usually an efficient method to improve thermal stability. The
P21/n with a calculated density of 1.746 g cm−3. The salt was decomposition temperatures of the salts range from 151 °C (3)
formed by the transfer of protons from the N2 and N4 groups to 235 °C (5), which are much higher than that of compound 1
of precursor 1 to two diaminoguanidine molecules (Fig. 3a). (92 °C). Salt 5 exhibits the highest thermal stability, which was
The length of the intramolecular hydrogen bond between N3– found to be superior to that of 1,3,5-trinitro-1,3,5-triazinane
H3⋯O2 is 2.173(1) Å. The dihedral angles between the fused- (RDX) (Td = 204 °C). Moreover, increasing the amino substitu-
triazole backbone and the three nitro groups are 3.42°, 9.25°, ent in analogous guanidine cations gives rise to a decrease in
and 87.33°, respectively, while those between the backbone the thermal stability, as salts 5, 6 and 7 decompose at 235 °C,
and the two cations are 6.93°, and 33.35°, respectively. The 184 °C and 174 °C, respectively.14
packing structure of salt 7 also shows a wave-like stacking with
Density is one of the most important properties contribut-
a layer distance of 3.196 Å. The dihedral angle between the two ing to the performance of energetic materials. The density of
370 | Dalton Trans., 2020, 49, 368–374
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within the range of HEDMs, and are higher than that of RDX
(d = 1.80 g cm−3).
Oxygen balance (OB) indicates the degree to which an explo-
sive can be oxidized. All of the salts possessed negative OB
values ranging from −42.8 (7) to −11.3% (3), and high nitrogen
and oxygen contents up to 87.31%. The dihydroxylammonium
salt 3 has the highest negative OB value (−11.3%), which is
substantially higher than that of RDX (−21.6%). Despite an
excellent OB value (−8.3%), compound 1 is too acidic to be
applied in practical applications, due to the strong electron-
withdrawing inductive effect of the three nitroamine groups.
Heat of formation (ΔfH) is fundamentally important for
evaluating the energetic performance of explosives. More posi-
tive values lead to potentially better detonation properties. The
ΔfH of the anion is 460.18 kJ mol−1, as calculated based on the
isodesmic reactions (Scheme 3) using the Gaussian 09
(Revision A.02)16 software package (see the ESI†). The cation
values are provided in the literature.17 The positive ΔfH values of
all salts are much higher than that of RDX (ΔfH = 92.6 kJ mol−1),
and range from 382.5 (2) to 869.9 kJ mol−1 (7) as computed using
the Born–Haber energy cycle (Scheme 4, ESI† for details).
The detonation pressures (P) and velocities (vD) of the new
energetic salts were determined using the EXPLO5 program
(Version 6.01), and calculated based on the density and ΔfH.18
The detonation pressures range from 27.6 (5) to 41.1 GPa (3),
while the detonation velocities range from 8519 (5) to
9518 m s−1 (3). Despite the low density of the dihydrazinium
salt 4 (d = 1.65 g cm−3), its detonation velocity (vD = 8739 m
Fig. 3 (a) Crystal structure of compound 7. (b) Packing diagram of 7
viewed towards the planes h, k, and l = 0.56, 0.01, and 17.06. The
cations are omitted for clarity.
compound 1 is 1.85 g cm−3, while the densities of the salts
range from 1.65 (4) to 1.89 g cm−3 (3), as measured using a gas
pycnometer (Table 1). The low density of salt 4 is attributed to
its shaggy feather-like shape when recrystallized from hot
water. In contrast, the high densities of salts 2 and 3 fall
Scheme 3 Isodesmic reaction for the anion of compound 1.
Table 1 Physiochemical properties and detonation parameters of compounds 1–7
Comp.
1
2
3
4
5
6
7
RDXm
HMXm
Tm a (°C)
Td b (°C)
ρc (g cm−3
Nd (%)
dec
92
1.85
53.29
86.49
−8.3
—
—
—
—
—
122
172
dec
151
dec
189
dec
235
dec
184
dec
174
dec
204
dec
280
)
1.86
56.34
86.04
−22.3
1330.4
382.5
36.9
9292
8
1.89
51.27
87.31
−11.3
1291.6
507.6
41.1
9518
5
1.65
59.48
86.66
−24.9
1226.6
773.5
30.2
8739
6
1.73
58.47
82.04
−41.3
1183.8
428.2
27.6
8519
6
1.71
60.86
82.81
−42.1
1147.4
647.6
28.4
8646
5
1.75
62.94
83.48
−42.8
1128.3
869.9
31.2
9017
4
1.80
37.84
81.06
−21.6
—
70.3
34.9
8795
7
1.91
37.84
81.06
−21.6
—
70.4
39.2
9144
7
N + Oe (%)
OBf (%)
ΔfHL g (kJ mol−1
)
ΔfHsal h (kJ mol−1
)
Pi (GPa)
vD (m s−1
)
j
ISk (J)
FSl (N)
—
192
108
140
252
192
120
120
120
a Melting point (onset temperature). b Thermal decomposition temperature (peak temperature). c Measured density (gas pynometer). d Nitrogen
content. e The sum of nitrogen and oxygen contents. f Oxygen balance. g Calculated molar lattice energy. h Calculated molar enthalpy of the for-
mation of salts (ΔfH anion = 460.18 kJ mol−1 calculated from Gaussian 09). i Detonation pressure. j Detonation velocity. k Impact sensitivity.
l Friction sensitivity (BAM friction apparatus). m From ref. 15.
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General methods
1H, 13C NMR spectra were recorded on a 600 MHz nuclear
magnetic resonance spectrometer operating at 600 and
150 MHz, respectively. Chemical shifts are reported relative to
TMS for 1H and 13C NMR spectra. The solvent was [D6]
dimethyl sulfoxide ([D6]DMSO) unless otherwise specified. The
melting and decomposition points were recorded using a
differential scanning calorimeter (DSC) and a NETZSCH STA
449F3 equipment at a heating rate of 5 °C min−1 in a dynamic
nitrogen atmosphere (flow rate = 50 mL min−1). The infrared
spectra were recorded using KBr pellets. Densities were
measured at 25 °C using a Micromeritics AccuPyc II1340 gas
pycnometer. Elemental analyses were performed using an
Elementar Vario MICRO CUBE (Germany) elemental analyzer.
Scheme 4 Born–Haber cycle for the formation of salts.
s−1) was comparable to that of RDX (vD = 8795 m s−1). This is
likely due to the high heat of formation (ΔfH = 773.5 kJ mol−1
)
of salt 4. With the highest ΔfH value (869.9 kJ mol−1), salt 7
displays a detonation velocity of 9017 m s−1, slightly lower
than that of HMX (vD = 9144 m s−1) but exceeds that of RDX.
The diammonium salt 2 possesses a high density of d = 1.86 g
cm−3 and a good OB of −22.3%, thus confirming its excellent
detonation performance (vD = 9292 m s−1 and P = 36.9 GPa),
which is superior to that of RDX (vD = 8795 m s−1 and P = 34.9
GPa). Due to the highest density (d = 1.89 g cm−3) and OB
(−11.3%), dihydroxylammonium salt 3 exhibits excellent deto-
nation performance (vD = 9518 m s−1 and P = 41.1 GPa), which
is superior to that of HMX (vD = 9144 m s−1 and P = 39.2 GPa).
Friction sensitivity (FS) and impact sensitivity (IS) measure-
ments were determined using friction testing and standard
BAM drop hammer techniques, respectively.19 All of the ener-
getic salts are less sensitive than CL-20 (IS = 4 J and FS = 94 N),
with IS values ranging from 4 (7) to 8 J (2), and FS values
ranging from 108 (3) to 252 N (5).
X-ray crystallography
Crystals of 5·H2O, 6·0.72H2O and 7 were removed from the
flask and covered with a layer of hydrocarbon oil. A suitable
crystal was then selected, attached to a glass fiber, and placed
in the low-temperature nitrogen stream. Data for 5·H2O were
collected at 189 K (λ = 1.54184 Å), and for 6·0.72H2O (λ =
0.71076 Å) and 7 (λ = 1.54184 Å) were collected at 150 K. Data
collection and reduction were performed and the unit cell was
initially refined by using the CrystalClear-SM Expert 2.0 r2 soft-
ware.20 The reflection data were also corrected for Lp factors.
The structure was solved by direct methods and refined by the
least squares method on F2 using the SHELXTL-97 system of
programs.21 The structures were solved in the space group P1
ˉ
for 5·H2O, P21/c for 6·0.72H2O, and P21/n for 7, by an analysis
of systematic absences. In this all-light-atom structure the
value of the Flack parameter did not allow the direction of
polar axis to be determined and Friedel reflections were then
merged for the final refinement. Details of the data collection
and refinement are given in Table S1 (ESI†). CCDC 1947617
(5·H2O), CCDC 1947615 (6·0.72H2O) and CCDC 1947616 (7)
contain the supplementary crystallographic data for this
paper.†
3,6,7-trinitro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazole (1). 3,6,7-
Triamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazole (TATOT) was
prepared according to the procedure described in the litera-
ture.10 At 0 °C, 1.54 g (10.0 mmol) TATOT was dissolved in
conc. sulfuric acid (15 g). Then fuming nitric acid (4.5 mL) was
added below −10 °C. After stirring over 4 h at −5 °C, the reac-
tion mixture was poured into crushed ice. The precipitate was
filtered, washed with acetonitrile and dried over CaCl2 to offer
1 (yield 80%). Yellow solid, d.p. 89 °C. 1H NMR ([D6]DMSO,
600 MHz, 25 °C, TMS): δ = 7.50 (s, br) ppm. 13C NMR ([D6]
DMSO, 150 MHz, 25 °C): δ = 156.63, 144.61, 143.00 ppm. IR
(KBr): 3333, 2985, 2788, 1674, 1624, 1584, 1542, 1480, 1440,
1393, 1325, 1264, 1131, 1085, 1009, 951, 831, 805, 713, 631,
582 cm−1. MS (ESI): 288 (M − H)−. Anal. calcd for C3H3N11O6:
C 12.46, H 1.05, N 53.29; found C 12.39, H 1.14, N 53.40.
General procedures for the preparation of energetic salts
Conclusions
A facile approach to synthesize energetic 3,6,7-trinitroimino-
7H-[1,2,4]triazolo[4,3-b][1,2,4]triazolate salts was explored. The
structures of salts 5, 6 and 7 were determined by single crystal
X-ray diffraction. The densities of these salts are between 1.65
(4) and 1.89 g cm−3 (3), whilst their oxygen balances are
between −42.8% (7) and −11.3% (3). All new salts show good
thermal stabilities (>170 °C) except 3. Most of them have
acceptable sensitivities and attractive detonation properties to
compete positively with RDX. The detonation performance
and sensitivity of salt 2 (vD = 9292 m s−1, P = 36.9 GPa, IS = 8 J,
and FS = 192 N) are superior to those of RDX. Salt 3 exhibits
acceptable sensitivity (IS = 5 J and FS = 108 N) and excellent
detonation performance (vD = 9518 m s−1 and P = 41.1 GPa)
which are superior to those of HMX. These advantages suggest
that these materials may well have promising applications as
high-energy-density materials.
Experimental section
Caution! Although we experienced no difficulties in handling
these energetic materials, small scale and best safety practices 2–4. Compound 1 (578 mg, 2 mmol) was dispersed in 20 mL
(leather gloves and face shield) are strongly encouraged!
water at room temperature followed by adding two equivalents
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of free base (ammonium hydroxide (25%) or hydroxylamine
Bis(diaminoguanidinium)
3,6,7-trinitroimino-7H-[1,2,4]
(50%) or hydrazine hydrate (99%)) in one portion. After stir- triazo lo[4,3-b][1,2,4]triazolate (7). 1,3-Diaminoguanidine
ring at 70 °C for 4 h, the solvent was evaporated in vacuo and monohydrochloride (502 mg, 4 mmol) was added to a solution
the residue was crystallized from water.
Diammonium
of NaOH (160 mg, 4 mmol) in H2O (20 mL) and the resulting
3,6,7-trinitroimino-7H-[1,2,4]triazolo[4,3-b] mixture was stirred at room temperature for 10 min. Then
[1,2,4]-triazolate (2). Yellow solid (549 mg, 85%). 1H NMR ([D6] compound 1 (578 mg, 2 mmol) was added and the mixture
DMSO, 600 MHz, 25 °C, TMS): δ = 7.14 (s) ppm. 13C NMR ([D6] was stirred at 70 °C for 4 h. The hot solution was evaporated in
DMSO, 150 MHz, 25 °C): δ = 159.22, 145.64, 141.85 ppm. IR vacuo and the residue was crystallized from water. Yellow stick
1
(KBr): 3599, 3544, 3451, 3206, 1644, 1571, 1527, 1477, 1422, crystal (869 mg, 93%). H NMR ([D6]DMSO, 600 MHz, 25 °C,
1278, 1239, 1138, 1064, 1002, 952, 842, 802, 764, 742, 716, TMS): δ = 13.82 (s, 1H), 8.58 (s, 4H), 7.15 (s, 4H), 4.60 (s, 8H),
582 cm−1. Anal. calcd for C3H9N13O6: C 11.15, H 2.81, N 56.34; ppm. 13C NMR ([D6]DMSO, 150 MHz, 25 °C): δ = 160.17,
found C 11.17, H 2.78, N 56.30.
159.11, 145.59, 141.79 ppm. IR (KBr): 3451, 3337, 3240, 1676,
Dihydroxylammonium 3,6,7-trinitroimino-7H-[1,2,4]triazolo 1572, 1535, 1472, 1417, 1292, 1183, 1080, 1004, 953, 842, 800,
[4,3-b][1,2,4]triazolate (3). Recrystallization from ethanol gave 767, 713, 639, 575 cm−1. Anal. calcd for C5H17N21O6: C 12.85,
1
yellow powder (483 mg, 68%). H NMR ([D6]DMSO, 600 MHz, H 3.67, N 62.94; found C 12.86, H 3.64, N 62.95.
25 °C, TMS): δ = 10.52 (s, br) ppm. 13C NMR ([D6]DMSO,
150 MHz, 25 °C): δ = 159.14, 145.59, 141.76 ppm. IR (KBr):
3075, 2725, 1623, 1548, 1469, 1414, 1329, 1152, 1085, 1008, 963, Conflicts of interest
866, 813, 766, 706, 685, 634 cm−1. Anal. calcd for C3H9N13O8: C
10.14, H 2.55, N 51.27; found C 10.08, H 2.59, N 51.29.
There are no conflicts to declare.
Dihydrazinium
3,6,7-trinitroimino-7H-[1,2,4]triazolo[4,3-
b][1,2, 4]triazolate (4). White solid (579 mg, 82%). 1H NMR
([D6]DMSO, 600 MHz, 25 °C, TMS): δ = 7.26 (s, br) ppm. 13C
NMR ([D6]DMSO, 150 MHz, 25 °C): δ = 159.12, 145.66,
141.80 ppm. IR (KBr): 3339, 3282, 3147, 2625, 1649, 1616,
1576, 1541, 1479, 1428, 1398, 1340, 1282, 1236, 1202, 1101,
1072, 1001, 967, 862, 809, 770, 704, 632, 469 cm−1. Anal. calcd
for C3H9N13O8: C 10.20, H 3.14, N 59.48; found C 10.22, H
3.18, N 59.39.
Acknowledgements
The authors gratefully acknowledge the support of the NSFC
(No. 21602209), the Applied Basic Research Programs of
Science and Technology Department of Shanxi Province (No.
201701D221049), the STIP of Higher Education Institutions in
Shanxi (No. 201658), the Science Foundation of North
University of China (No. 2016018), and the Open Fund of State
Key Laboratory of Deep Buried Target Damage, North
University of China (No. DXMBJJ2018-06).
Bis(guanidinium) 3,6,7-trinitroimino-7H-[1,2,4]triazolo[4,3-
b][1,2, 4]triazolate (5). Compound 1 (578 mg, 2 mmol) was dis-
persed in 40 mL of water at room temperature followed by
adding 360 mg of bisguanidinium carbonate in portions
(2 mmol). After stirring at 70 °C for 4 h, the solvent was evap-
orated in vacuo and the residue was crystallized from water.
Yellow stick crystal (773 mg, 95%). 1H NMR ([D6]DMSO,
Notes and references
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(b) G. Zhao, C. He, P. Yin, G. H. Imler, D. A. Parrish and
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(c) C. He, H. Gao, G. H. Imler, D. A. Parrish and
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(d) Y. Liu, C. Shen and M. Lu, CrystEngComm, 2019, 21,
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600 MHz, 25 °C, TMS): δ = 13.82 (s, 1H), 6.96 (s, 12H) ppm. 13
C
NMR ([D6]DMSO, 150 MHz, 25 °C): δ = 159.09, 158.33, 145.58,
141.80 ppm. IR (KBr): 3423, 3189, 1648, 1591, 1529, 1451,
1410, 1322, 1139, 1084, 1009, 987, 956, 859, 806, 770, 737, 709,
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58.47; found C 14.74, H 3.25, N 58.45.
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zolo [4,3-b][1,2,4]triazolate (6). Compound 1 (578 mg, 2 mmol)
was dispersed in 40 mL of water at room temperature followed
by adding 544 mg of bisguanidinium carbonate in portions
(4 mmol). After stirring at 70 °C for 4 h, the solvent was evap-
orated in vacuo and the residue was crystallized from water.
Yellowish-brown stick crystal (830 mg, 95%). 1H NMR
([D6]DMSO, 600 MHz, 25 °C, TMS): δ = 13.82 (s, 1H), 8.61 (s,
2H), 7.27 (s, 4H), 6.77 (s, 4H), 4.70 (s, 4H) ppm. 13C NMR
([D6]DMSO, 150 MHz, 25 °C): δ = 159.19, 159.09, 145.57,
141.80 ppm. IR (KBr): 3447, 3263, 1671, 1574, 1528, 1473,
1409, 1270, 1200, 1145, 1075, 1006, 953, 837, 800, 767, 741,
712, 638, 602, 494 cm−1. Anal. calcd for C5H15N19O6: C 13.73,
H 3.46, N 60.86; found C 13.70, H 3.48, N 60.90.
This journal is © The Royal Society of Chemistry 2020
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