Imino-bridged N-rich energetic materials: C4H3N17and their derivatives assembled from the powerful combination of four tetrazoles

Article abstract of DOI:10.1039/d1ce00674f

This study reports the synthesis of a series of novel imino-bridged N-rich energetic compounds, namely C₄H₃N₁₇(N%: 82.4) and their derivatives, which were formed by four tetrazole (CN4) moieties. C₄N₁₇^3?could be acidified by different concentrations of HCl and N-rich anions such as C₄H₂N₁₇^?and the neutral compound3(C₄H₃N₁₇) could be obtained. The new compounds all exhibit good energetic performance (D: 8023-9668 m s^?1; Td: 169-277 °C; IS > 25 J; FS > 252 N). Remarkably, the ammonia oxide adduct compound8(C₄H₁₅N₂₁O₄) was exceedingly powerful (D: 9668 m s^?1) similar to CL-20 (9706 m s^?1) and showed good stability (Td: 168 °C; IS > 40 J; FS > 360 N). Moreover, compound11(C₄H₈NaN₁₉) exhibits not only the thermal stability and high density of metallic salts but also the mechanical stability of nonmetallic salts, which provides an important strategy for the design and synthesis of energetic materials. Among them, compounds3,4, and6-11were characterizedviasingle-crystal diffraction to further confirm their exact molecular structure and arrangement.

Full text of DOI:10.1039/d1ce00674f

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Imino-bridged N-rich energetic materials: C4H3N17
and their derivatives assembled from the powerful
combination of four tetrazoles†
Cite this: CrystEngComm, 2021, 23,
5377
*
Haiyan Li, Yaxin Liu and Zhiwen Ye
Yifei Liu,
Zhen Dong,
Rui Yang,
This study reports the synthesis of a series of novel imino-bridged N-rich energetic compounds, namely
3−
C4H3N17 (N%: 82.4) and their derivatives, which were formed by four tetrazole (CN4) moieties. C4N17
−
could be acidified by different concentrations of HCl and N-rich anions such as C4H2N17 and the neutral
compound 3 (C4H3N17) could be obtained. The new compounds all exhibit good energetic performance
(D: 8023–9668 m s−1; Td: 169–277 °C; IS > 25 J; FS > 252 N). Remarkably, the ammonia oxide adduct
compound 8 (C4H15N21O4) was exceedingly powerful (D: 9668 m s−1) similar to CL-20 (9706 m s−1) and
showed good stability (Td: 168 °C; IS > 40 J; FS > 360 N). Moreover, compound 11 (C4H8NaN19) exhibits
not only the thermal stability and high density of metallic salts but also the mechanical stability of
nonmetallic salts, which provides an important strategy for the design and synthesis of energetic materials.
Among them, compounds 3, 4, and 6–11 were characterized via single-crystal diffraction to further confirm
their exact molecular structure and arrangement.
Received 21st May 2021,
Accepted 15th June 2021
DOI: 10.1039/d1ce00674f
rsc.li/crystengcomm
building blocks for the synthesis of N-rich compounds.5
Among them, the tetrazole group, a typical N-rich aromatic
Introduction
Given the increasing demands for high performance and the
growing safety and environmental concerns, traditional
explosives such as RDX, HMX, and CL-20, which generate
energy through redox reactions, are increasingly unable to
meet the requirements for specific applications in the military
and civil fields. Therefore, the combination of these issues
has prompted numerous researchers to focus on the design
and synthesis of novel energetic materials (EMs), which must
fulfill several key requirements, such as tailored energetic
performance, insensitivity toward destructive stimuli, and
substantial thermal stability.1
From the standpoint of realizing excellent EMs, effective
synthesis strategies for energetic compounds mainly focus on
reducing sensitivity and increasing energy.2 At present, N-rich
compounds are prospective alternative energetic ingredients
because of their high heat of formation (HOF), high density,
and good oxygen balance.3 Compared to the traditional EMs
mentioned earlier (RDX, HMX and CL-20), N-rich energetic
compounds are environmentally friendly, mainly releasing N2
after decomposition.4 N-rich heterocyclic backbones such as
tetrazoles, triazoles, azines and oxadiazoles are essential
ring with surprisingly higher thermal stability and featuring
a high nitrogen content (N%: 80.0) and high positive HOF
(4.77 kJ g−1), is an important ingredient of energetic
compounds.6 Tetrazole energetic derivatives have been
studied widely because of their interesting energetic
properties and unique chemical structures.16a
In the research of energetic materials, many energetic
compounds with good energy performance have been
developed
based
on
tetrazole.
For
example,
1-diazidocarbamoyl-5-azidotetrazole7 (C2N14, Fig. 1A) exhibits
a
density of 1.723
g
cm−3, thermal decomposition
temperature of 110 °C, HOF of 1459 kJ mol−1, detonation
School of Chemical Engineering, Nanjing University of Science and Technology,
Nanjing 210094, P.R. China. E-mail: yezw@njust.edu.cn
† Electronic supplementary information (ESI) available. CCDC 2034088,
2047779, 2050808, 2051823, 2051824, 2053784, 2072406 and 2079019. For ESI
and crystallographic data in CIF or other electronic format see DOI: 10.1039/
d1ce00674f
Fig. 1 Selected N-rich energetic compounds containing (A) azide, (B)
azo, or (C) nitro groups.
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velocity of 8960 m s−1 and detonation pressure of 33.9 GPa.
Similarly, 1,1′-azobis(tetrazole)8 (C2H2N10, Fig. 1B) and N-(1-
((1H-tetrazol-5-yl)methyl)-1H-tetrazol-5(4H)-ylidene) nitramide9
(C3H4O2N9, Fig. 1C) also have high detonation performance.
Unfortunately, high energetics and good stability are usually
mutually exclusive aspects.10 They show unacceptable
mechanical stability toward external stimuli which may be
related to the presence of [–N3], [–NO2], and [–NN–] in the
molecule.9,11,12 According to the previous reports, tetrazole
rings linked by [–NH–], [–CH2–], and [CO] bridges can form a
planar symmetric structure with better stability.13–15 From the
theoretical calculations of HOF for generating bistetrazoles,
C–N linked bistetrazoles compounds have higher energy
densities than the C–C linked ones.16 Herein, based on the
above theoretical basis as a guide, we designed and synthesized
a series of novel N-rich energetic compounds, namely C4H3N17
and their derivatives, which were formed by four tetrazole
moieties linked by the [–NH–] bridge and C–N bond. As
expected, they all have good energetic properties and stability.
Importantly, the facile procedure, high yield and low cost of
these compounds enable them to possess great potential for
practical applications.
such as KOH and NH3·H2O to form a series of novel energetic
metal–organic frameworks (10 and 11). The synthesis of
compound 11 provides an important strategy for the
development of novel energetic materials.
Structural analysis
To further study the exact molecular structure and
arrangement of these new compounds, colorless single
crystals of compounds 3, 4, and 6–11, suitable for X-ray
diffraction, were obtained by slowly evaporating the solvent
from the applicable saturated solution at 25 °C. The crystal
structures with 3D frameworks are shown in Fig. 2. Detailed
crystallographic data are provided in the ESI.†
Compound 3·2DMSO crystallizes in the monoclinic space
group C2 with two formula units in its asymmetric unit and
exhibits a calculated density of 1.568 g cm−3 at 296 K. The
presence of two DMSO molecules affects the tight
arrangement of the molecules, resulting in a low density. The
four tetrazole rings are almost coplanar which is evident
Results and discussion
Synthesis
The detailed synthetic pathway is shown in Scheme 1. To
introduce the tetrazole group, the sodium salt of compound
1 was reacted with cyanogen azide to yield trisodium di(1′H-
[1,5′-bitetrazol]-5-yl)amine compound 2. Compounds 3 and 9
were obtained after acidification to different extents with
hydrochloric acid. Compound 3 was deprotonated with a
base such as KOH, NH3·H2O, C2H10N6H2CO3, N2H4·H2O, and
NH2OH to form a series of high-energy ionic salts (4–8).
Besides, the ammonia oxide adduct compound
8 was
synthesized via treating compound with excess
3
hydroxylamine. Compound 9 was deprotonated with a base
Fig.
2 Molecular structures of compounds (a) 3·2DMSO, (b)
4·2.25H2O, (c) 6, (d) 7·H2O, (e) 8·2H2O, (f) 9·3CH3OH, (g) 10·2.25H2O
and (h) 11·H2O.
Scheme 1 Preparation of compounds 2–9.
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from the torsion angles C2–N5–C1–N1 (2.2), N3–N2–C1–N1
(179.7), and N8–N9–C2–N5 (180.0). The bond length of C2–
N5 (1.398(4) Å) is slightly longer than that of C1–N1 (1.370(3)
Å), which is due to a π–π conjugation between the C2–N5
bond and two aromatic tetrazole rings.6
Compound 4·2.25 H2O crystallizes in the monoclinic space
group C2/c with two formula units in its asymmetric unit and
exhibits a high calculated density of 1.992 g cm−3. In the
entire molecular structure, three K joins with N to form a
chelate ring structure containing metal ions and each anion
can coordinate with twelve potassium cations.
3−
−
The other C4N17 and C4N17H2 salts (compounds 6,
¯
7·H2O and 8·2H2O) crystallize in the triclinic space group P1
with two formula units in the unit cell and exhibit crystal
densities of 1.625, 1.648, and 1.709 g cm−3 at 296 K,
respectively. Notably, the structure of compound 6 is non-
planar, which may be related to the rotation of the C1–N3
bond caused by the asymmetric hydrogen-bonding networks
formed by the C4N173− anion and guanidine cation (Fig. 3).
Compound 9·3CH3OH and compound 11·H2O crystallize
Fig. 4 (a–d) Packing diagrams for compounds 4, 9, 10 and 11.
Physical and chemical properties
In view of these novel compounds consisting of only four
tetrazoles linked to the [–NH–] bridge and having a high
nitrogen content, it would be interesting to study their key
physical and energetic properties such as thermal stability,
density, HOF, detonation performance, and mechanical
sensitivity to examine their potential for use as high-energy
density materials (HEDMs) (Table 2).
¯
in the triclinic space group P1 with two formula units in
their asymmetric unit and exhibit a calculated density of
1.517, 1.603 g cm−3 at 296 K, respectively, and the cations
are composed of a sodium ion and two ammonium ions in
compound 11. Compound 10·2.25 H2O crystallizes in the
triclinic space group C2/c with four formula units in its
asymmetric unit and exhibits a high calculated density of
1.946 g cm−3 at 296 K. In the entire molecular structure,
two K and one Na joins with N to form a chelate ring
structure containing metal ions. High energy MOFs (HE-
MOFs) (4 and 9–11) are synthesized by the assembly of
metal ions and high nitrogen bidentate and (or)
multidentate ligands. These derivative ligands are a unique
class of energetic compounds with a stable structure and
high nitrogen content (Fig. 4).17
The thermal stability was evaluated by using differential
scanning calorimetry (DSC) (ESI†). The results show that
neutral compound
compounds 2, 4, 9, 10, and 11 demonstrate
3
decomposes at 198 °C, whereas
high
a
decomposition temperature up to 251 °C, 241 °C, 249 °C, 247
°C, and 206 °C, respectively. In particular, compound 6
exhibits the highest decomposition temperature of 277 °C
and has the potential to be used as a heat-resistant energetic
material.20 Compounds 5, 7 and 8 possess slightly lower
decomposition temperatures of 191 °C, 176 °C, and 168 °C,
respectively. Among them, compound 8 exhibits a two-stage
Symmetric structures and the layer-by-layer assembly of
molecular arrangements are ubiquitous in nature and
possibly possess excellent balance and stability.18,19 As
expected, in all the structures discussed in this study except
for compound 6, their molecular structures are arranged in
layers, and the structure of C4H3N17 is clearly planar
−
3−
symmetric. Similarly, their anions, C4H2N17 and C4N17
,
with dihedral angles of 4.37° and 9.41°, also have nearly
planar structures (Fig. 5).
Fig. 3 (a) Molecular structure of compound 6; (b) packing diagram for
compound 6; hydrogen bonds are shown in sky-blue lines; (c) non-
covalent interactions (NCIs) surrounding C4N173− in compound 6.
Fig. 5 Comparison of the arrangement, symmetry and planarity of (a
3−
and d) C4H4N17, (b and e) C4H2N17− and (c and f) C4N17
.
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as RDX (0.42 kJ g−1) and HMX (0.25 kJ g−1),21 all these
Table
1 Bond angles, bond lengths, and densities of the selected
compounds have a better positive HOF (1.67–5.32 kJ g−1).
compounds 3, 4, 7, 8, 10 and 11
Compd Bond angles Value/° Bonds Lengths/Å Density/g cm−3
Detonation
performance
was
determined
by
comprehensive analysis of the molecular formula, density
and HOF of the compound using the EXPLO 5–6.05.02
program. Compounds 3 and 9 have a high detonation
velocity (8650 m s−1 and 8641 m s−1) close to RDX (8795 m
s−1) and compound 7 also has a high detonation velocity
(9063 m s−1) close to HMX (9144 m s−1).21 Remarkably, the
ammonia oxide adduct compound 8 exhibits the highest
detonation performance (D: 9668 m s−1; P: 35.10 GPa) similar
to CL-20 (9706 m s−1). To our knowledge, there are a few
reports on ammonia oxide adducts (Fig. 6). The presence of
ammonia oxide can produce more hydrogen bonds thus
improving the density and detonation properties of the
energetic compounds. They have the most promising
prospect of replacing the energetic materials in common
use.2a,22
3
4
C1–N1–C1′
C2–N9–C3
122.90 C1–N1 1.273
116.55 C2–N9 1.333
C3–N9 1.328
117.35 C1–N1 1.344
C3–N1 1.336
116.54 C1–N1 1.337
C3–N1 1.342
116.80 C1–N1 1.340
C3–N1 1.341
1.72
2.05
7
C1–N1–C3
C1–N1–C3
C1–N1–C3
C1–N1–C3
1.70
1.82
2.02
1.76
8
10
11
117.30 C1–N1 1.344
C3–N1 1.341
decomposition process which may be related to the presence
of hydroxylamine molecules in the molecule.26
The density of the samples was measured using a gas
pycnometer. The metal salts 2, 4, 9, 10 and 11 had higher
measured densities of 1.76–2.05 g cm−3. Compounds 3 and
5–8 do not have a tightly bound metallic bond structure
within the molecule as compared to the metal salts, and they
exhibit slightly lower measured densities, which were in the
range of 1.63–1.82 g cm−3. Density is inseparable from the
molecular structure of a compound. As shown in Table 1, the
bond angle of the [–NH–] group in compound 3 (C4H3N17) is
The mechanical sensitivities were evaluated using the
standard BAM method. As shown in Table 2, all the newly
synthesized compounds show low mechanical sensitivity. The
impact sensitivity and friction sensitivity of the
corresponding metal salts (IS > 25 J; FS > 252 N) show
slightly higher sensitivity than those of neutral compound 3
with an IS of 35 J and FS of 360 N. In particular, the good
mechanical stability (IS > 35 J; FS > 360 N) of compound 11
is related to the fact that the cation is composed of a sodium
ion and two ammonium ions, in which the ammonium ion
helps to form a complex hydrogen bond network and reduces
the mechanical sensitivity of the compound. By contrast, the
metal-free salt compounds (5, 7, and 8) exhibit significantly
lower mechanical sensitivities (IS > 37.5 J; FS > 360 N).
Additionally, the slightly lower FS (324 N) of compound 6
may be related to the fact that the molecular structure is not
planar.
3−
122.90°, while its bond angle range in C4N17 is 116.55° to
117.35°. In addition, the bond length of the C–N bond
directly connected with [–NH–] was also analyzed, and the
bond length ranged from 1.273 Å to 1.344 Å. A short bond
length and small angle can form a more compact molecular
structure, which is conducive to the high molecular density.
The energy source of the N-rich energetic materials
originates from the fracture of the nitrogen–nitrogen bonds.
Compounds 3 and 5–7 have high nitrogen contents up to
78.03–83.60%. Therefore, introducing tetrazole into the
energetic compounds can increase the HOF.21 Compared
with the currently commonly used energetic materials such
3−
The C4N17 anion presents a near-planar structure and
the hydrogen bonds (HBs, such as N–H⋯N, N–H⋯O and O–
H⋯N) can be formed between layers with cations such as
Table 2 Physical properties and energetic performance of compounds 2–9 compared with those of RDX, HMX and CL-20
db
Nc
ΔHfd
De
Pf
ISg
FSh
a
Compd
Td
2
3
4
5
6
7
8
9
251
198
238
191
277
179
168
249
247
206
230
280
221
1.88
1.72
2.05
1.69
1.63
1.70
1.82
1.84
2.02
1.76
1.80
1.91
2.04
67.05
82.34
59.02
82.33
78.03
83.61
69.82
76.52
61.47
77.08
37.84
37.84
38.36
256.48/0.72
1509.08/5.22
87.33/0.22
497.06/1.67
878.81/1.88
1017.37/2.64
877.669/2.08
1299.046/4.17
—
—
8650
—
8165
8023
9063
9668
8641
—
—
30.95
—
21.75
21.23
28.30
35.10
27.51
—
25
35
252
360
288
360
324
360
360
324
288
360
120
120
48
27.5
37.5
40
37.5
40
32.5
27.5
35
7.4
7.4
4
10
11
—
—
—
RDXi
HMXj
CL-20k
92.60/0.42
70.40/0.25
397.8/0.91
8795
9144
9706
34.9
39.2
45.2
a
b
c
Thermal decomposition temperature [°C] (onset, 5 K min−1). Density [g cm−3] (measured using a gas pycnometer; 298 K). Content of
nitrogen [%]. Heats of formation [kJ mol−1/kJ g−1]. Detonation velocity [m s−1]. Detonation pressure [GPa]. Impact sensitivity [J]. Friction
d
e
f
g
h
sensitivity [N]. Ref. 21a. j Ref. 21a. Ref. 21a.
i
k
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Fig.
6 (A and B) Selected N-rich energetic compounds and (C)
compound 8.
hydrazine or hydroxylamine. To further analyze the
differences in their stability, the non-covalent interactions
(NCIs) of compounds 3, 7 and 8 were studied using the
Gaussian,23 Multiwfn24 and VMD25 software programs. In
Fig. 7a–f, extensive hydrogen-bonding networks (sky-blue
lines) were observed in the packing system of compounds 3,
7 and 8. Compared to the bonds in neutral compound 3,
more strong hydrogen bonds were particularly observed in
the ammonia oxide adduct compound 8. A dense hydrogen-
bond-network is beneficial to the formation of compact
spatial structure, improving the mechanical stability of
materials.26
Fig.
8
(a–c) Hirshfeld surfaces of 3, 7, and 8, respectively; (d–f)
fingerprint plots for 3, 7, and 8, respectively; (g) individual atomic
contact percentage contribution to the Hirshfeld surfaces of 3, 7, and
8, respectively.
which are associated with hydrogen bonds, were present in
compounds 7 and 8 than in compound 3 (Fig. 8a–c). The
quantified non-covalent bond results are shown in Fig. 8g; in
the crystals of compounds 3, 7 and 8, the percentage of
hydrogen bonds was 53.6%, 59.3%, and 68.3%, respectively.
In contrast, the percentage of the N⋯N bond showed a
decreasing trend (17.6%, 13.50% and 10.80%). The
comprehensive analysis results are consistent with their
trend of increasing stability.
To further analyze the differences in their stability, the
associated Hirshfeld surfaces and the 2D fingerprint plots of
compounds 3, 7 and 8 were compared. More deep red dots,
Conclusions
In conclusion, highly ordered structures tend to exhibit
fascinating material properties. A family of novel N-rich high-
energetic compounds was synthesized based on four
tetrazoles and displayed a good balance between stability and
energy (D: 8023 m s−1–9668 m s−1; P: 23.95 GPa–35.10 GPa; IS
> 25 J; FS > 252 N). Furthermore, this work provides an
important strategy for the development of energetic
materials. Interestingly, compound 3 could be deprotonated
by excess hydroxylamine, and an ammonia oxide adduct
compound 8 was synthesized. It exhibits excellent energetic
preference (D = 9668 m s−1; P: 35.1 GPa; Td: 168 °C; IS > 40 J;
FS
potential as a captivating class of highly energetic materials.
In addition, new method for synthesizing energetic
> 360) which highlights their practical application
a
materials was reported in this paper. Thus, compound 11
was obtained and had excellent physical and chemical
properties.
Experimental section
Experimental procedures
Cautions! There have been no explosions when dealing with
these compounds, but we strongly encourage to take strict
precautions because of their high energy and mechanical
sensitivity.
Fig. 7 (a–c) Packing diagrams for compounds 3, 7 and 8. HBs are
shown in sky-blue lines; (d–f) NCIs surrounding C4N17H3 and C4N173− in
compounds 3, 7 and 8.
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˜
General methods
DMSO-d6): δ = 158.70, 155.62. IR (KBr): v = 3464.32, 3318.03,
2117.82, 1624.87, 1553.96, 1488.39, 1337.65, 1283.19, 1148.62,
1093.47, 1015.91, 973.54, 909.50, 795.05, 742.59, 668.30 cm−1.
Elemental analysis calcd for C4K3N17 (402.94): C 11.91, N
59.02%; found: C 11.94; N 58.97%.
All reagents of analytical grade were purchased from Energy
Chemical and used strictly in accordance with regulations.
1H and 13C NMR spectra were recorded on a Bruker 500 MHz
nuclear magnetic resonance spectrometer operating at 500
and 126 MHz, respectively. IR spectra were recorded
using KBr pellets with a Thermo Nicolet iS10 spectrometer.
Elemental analyses were carried out on a Vario EL III CHNOS
elemental analyzer. The melting and decomposition (onset)
points were measured on a differential scanning calorimeter
(Mettler Toledo DSC823e) at a scan rate of 5 K min−1.
Densities were confirmed at room temperature by using a
Micromeritics AccuPyc 1340 gas pycnometer. Impact and
friction sensitivity were obtained using a standard BAM
Fallhammer and a BAM friction tester.
Triammonium di(1′H-[1,5′-bitetrazol]-5-yl)amine (5). At 25
°C, compound 3 (0.289 g, 1 mmol) was suspended in 15 mL
acetonitrile and 27% aqueous ammonia (0.21 mL, 3 mmol)
was added drop-wise at room temperature and stirred for 2
a white precipitate was filtered and washed with
acetonitrile to give an amorphous white solid. White solid,
h;
1
0.307 g, yield: 89.5%. H NMR (500 MHz, DMSO-d6): δ = 7.56
(s, 12H). 13C NMR (126 MHz, DMSO-d6): δ = 158.25, 155.43.
˜
IR (KBr): v = 3462.62, 3320.44, 2117.84, 1625.34, 1601.11,
1557.53, 1507.19, 1470.15, 1440.68, 1410.02, 1338.15, 1159.25,
1105.70, 1080.30, 1023.77, 1012.89, 973.37, 905.90, 797.46,
743.68 cm−1. Elemental analysis calcd for C4H12N20 (340.28):
C 14.12, H 3.55, N 82.33%; found: C 14.15, H 1.01, N 82.29%.
Triguanidine di(1′H-[1,5′-bitetrazol]-5-yl)amine (6). At 25
°C, compound 3 (0.289 g, 1 mmol) was suspended in 15 mL
acetonitrile and guanidine carbonate (0.27 g, 1.5 mmol) was
added drop-wise at room temperature and stirred for 2 h; a
white precipitate was filtered and washed with acetonitrile to
give an amorphous white solid. White solid, 0.417 g, yield:
Syntheses
Trisodium di(1′H-[1,5′-bitetrazol]-5-yl)amine (2). At 0 °C,
cyanogen bromide (3.148 g, 30 mmol) was dissolved in 100
mL anhydrous acetonitrile to which sodium azide (6.825 g,
105 mmol) was added. The reaction mixture was stirred at 0
°C for 4 h. After the inorganic salt being filtered off, the
cyanogen azide solution was added to a solution containing
hydrated bis(1H-tetrazol-5-yl)amine (1.2825 g, 7.5 mmol)
which had been neutralized with sodium hydroxide (0.900 g,
22.5 mmol) in 40 mL water at ambient temperature. After
stirring over 6 h at ambient temperature, a white precipitate
was filtered and washed with acetonitrile to give an
amorphous white solid. White solid, 1.344 g, yield: 62%. 13C
89.4%. H NMR (500 MHz, DMSO-d6): δ = 7.12 (s, 18H). 13C
NMR (126 MHz, DMSO-d6): δ = 159.30, 158.03, 155.01. IR
1
˜
v = 3457.26, 3439.28, 3364.76, 3150.61, 1656.85,
(KBr):
1566.84, 1530.19, 1505.43, 1429.81, 1310.91, 1164.85, 1102.87,
1021.82, 737.55 cm−1. Elemental analysis calcd for C7H18N26
(466.47): C 18.03, H 3.89, N 78.08%; found: C 18.05, H 3.90,
N 78.04%.
˜
NMR (126 MHz, DMSO-d6): δ = 158.69, 155.62. IR (KBr): v =
3463.75, 3320.21, 2117.69, 1625.89, 1590.69, 1555.04, 1519.07,
1466.83, 1338.40, 1300.63, 1277.96, 1149.54, 1091.62, 1011.04,
970.74, 910.31, 796.99, 737.18 cm−1. Elemental analysis calcd
for C4Na3N17 (355.02): C 13.53, N 67.05%; found: C 13.56; N
67.01%.
Trihydrazinium di(1′H-[1,5′-bitetrazol]-5-yl)amine (7). At 25
°C, compound 3 (0.289 g, 1 mmol) was suspended in 15 mL
acetonitrile and 85% hydrazine hydrate (0.15 g, 3 mmol)
was added drop-wise at room temperature and stirred for 2
h;
a white precipitate was filtered and washed with
Di(2′H-[1,5′-bitetrazol]-5-yl)amine (3). At 0 °C, compound 2
(0.710 g, 2 mmol) was dissolved in 30 mL H2O. To this
solution, aq. 12 M HCl (1.5 mL) was slowly added dropwise
over 1 minute. The reaction mixture was stirred at 0 °C for 2
h, and a white precipitate was filtered and washed with
acetonitrile to give an amorphous white solid. White solid,
0.544 g, yield: 87%. 1H NMR (500 MHz, DMSO-d6): δ = 6.66
(s, 3H). 13C NMR (126 MHz, DMSO-d6): δ = 152.77, 152.02. IR
acetonitrile to give an amorphous white solid. White solid,
0.355 g, yield: 92.1%. 1H NMR (500 MHz, DMSO-d6): δ =
7.19 (s, 15H). 13C NMR (126 MHz, DMSO-d6): δ = 158.45,
˜
154.97. IR (KBr): v = 3462.62, 3320.44, 2968.75, 2117.47,
1622.94, 1602.29, 1551.84, 1503.63, 1469.73, 1338.40,
1286.41, 1157.66, 1148.29, 1120.83, 1089.05, 1025,77,
1012.16, 958.27, 944.82, 909.72, 733.80, 652.03 cm−1.
Elemental analysis calcd for C4H15N23 (385.33): C 12.47, H
3.92, N 83.61%; found: C 12.51, H 1.01, N 83.27%.
˜
v = 2172.99, 1680.48, 1647.97, 1607.10, 1557.19,
(KBr):
1480.44, 1404.99, 1352.81, 1125.82, 1080.44, 1034.62, 999.66,
918.91, 844.49, 769.01, 727.54, 709.44, 668.21 cm−1.
Elemental analysis calcd for C4H3N17 (289.19): C 16.61, H
1.05, N 82.34%; found: C 16.64, H 1.02, N 82.32%.
Tripotassium di(1′H-[1,5′-bitetrazol]-5-yl)amine (4). At 25
°C, compound 3 (0.289 g, 1 mmol) was suspended in 15 mL
acetonitrile and aqueous KOH (KOH: 0.168 g, 3 mmol; CH3-
CH2OH: 5 mL) was added drop-wise at room temperature
and stirred for 2 h; a white precipitate was filtered and
washed with acetonitrile to give an amorphous white solid.
White solid, 0.312 g, yield: 91.2%. 13C NMR (126 MHz,
Trihydroxylaminedi
(1′H-[1,5′-bitetrazol]-5-yl)amine
(hydroxylamine) (8). At 25 °C, compound 3 (0.289 g, 1 mmol)
was suspended in 15 mL acetonitrile and 50% hydroxylamine
hydrate (0.99 g, 15 mmol) was added drop-wise at room
temperature and stirred for 2 h; a white precipitate was
filtered and washed with acetonitrile to give an amorphous
1
white solid. White solid, 0.382 g, yield: 90.8%. H NMR (500
MHz, DMSO-d6): δ = 5.64 (s, 15H). 13C NMR (126 MHz,
˜
DMSO-d6): δ = 157.93, 155.45. IR (KBr): v = 3462.62, 3320.44,
2113.17, 1659.88, 1626.20, 1583,52, 1551,75, 1516.37, 1337.24,
1296.27, 1166.15, 1148.11, 1109.44, 1009.86, 998.97, 972,50,
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905.90, 795.05, 734.19 cm−1. Elemental analysis calcd for Notes and references
C4H15N21O4 (421.16): C 11.40, H 3.29, N 69.82, O 15.19%;
found: C 12.52, H 1.01, N 69.83, O 15.18%.
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0 °C,
compound 2 (0.710 g, 2 mmol) was dissolved in 30 mL H2O.
To this solution, aq. 12 M HCl (0.2 mL, 2 mmol) was slowly
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and washed with acetonitrile to give an amorphous white
1
solid. White solid, 0.616 g, yield: 86.6%. H NMR (500 MHz,
DMSO-d6): δ = 5.47 (s, 2H). 13C NMR (126 MHz, DMSO-d6): δ
˜
= 152.25, 151.79. IR (KBr): v = 3466.27, 3320.21, 2119.04,
1625.54, 1594.94, 1551.09, 1340.92, 1149.54, 1100.20, 1013.55,
973.26, 909.35, 791.95, 793.37, 580.70, 546.76 cm−1.
Elemental analysis calcd for C4H2NaN17 (311.17): C 15.44, H
0.65, N 76.52%; found: C 12.47, H 0.66, N 76.48%.
Bipotassium sodium di(1′H-[1,5′-bitetrazol]-5-yl)amine
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temperature and stirred for 2 h; a white precipitate was
filtered and washed with acetonitrile to give an amorphous
white solid. White solid, 0.306 g, yield: 91.5%. 13C NMR (126
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˜
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found: C 12.43, N 61.44%.
Biammonium sodium di(1′H-[1,5′-bitetrazol]-5-yl)amine
(11). At 25 °C, compound 9 (0.311 g, 1 mmol) was suspended
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1
0.306 g, yield: 88.6%. H NMR (500 MHz, DMSO-d6): δ = 7.66
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˜
v = 1632.95, 1584.70, 1553.32, 1520.45, 1424.11,
(KBr):
1163.56, 1078.19, 1030.06, 742.30, 563.12, 546.55 cm−1.
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2.34, N 77.09%; found: C 13.95, H 2.36, N 77.08%.
Conflicts of interest
14 (a) Y. A. Feng, H. Qiu, S. S. Yang, J. Du and T. L. Zhang,
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There are no conflicts to declare.
Acknowledgements
The authors are most grateful to Prof. Chong. Zhang (Nanjing
University of Science and Technology) for his help on the
detonation performance calculation and mechanical
sensitivity test. Special thanks to M.S. Ling Chen for her help
and professional advice on the NMR test and NMR spectral
analysis and we also sincerely thank Dr. Qi Sun (Beijing
Institute of Technology), M.S. Zhe. Xing and M.S. Siyuan.
Chen for their professional advice on article writing.
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