(Picrylamino)-1,2,4-triazole Derivatives - Thermally Stable Explosives

Article abstract of DOI:10.1002/ejic.201501435

3-(Picrylamino)-1,2,4-triazole (PATO) and 3-amino-5-(picrylamino)-1,2,4-triazole (APATO) were synthesized and analyzed. During the syntheses of the compounds, two interesting side-products were isolated. The reactions of PATO and APATO with different nitrogen-rich bases, such as ammonia, hydrazine, triethylamine, and triaminoguanidine, resulted in the deprotonation of both triazole compounds and the formation of the corresponding salts (cation/anion ratio = 1:1). The compounds were obtained at ambient temperature in H₂O or EtOH as qualitatively pure products with the characteristic properties of secondary explosives. The compounds were characterized by multinuclear NMR, IR, and Raman spectroscopy as well as mass spectrometry. The low-temperature structures of two compounds were determined by single-crystal X-ray diffraction. The thermal stabilities were measured by differential scanning calorimetry (DSC). The sensitivities were determined through the BAM drophammer and friction tests. The heats of formation were calculated by the atomization method from the CBS-4M enthalpies and the densities determined by X-ray diffraction or pycnometry. Several detonation parameters including the detonation pressure, detonation velocity, detonation energy, and detonation temperature were computed with the EXPLO5 code.

Full text of DOI:10.1002/ejic.201501435

DOI: 10.1002/ejic.201501435
Full Paper
Thermally Stable Explosives
(
Picrylamino)-1,2,4-triazole Derivatives – Thermally Stable
Explosives
[a]
[a]
[a]
[a]
Zoe L. Chioato, Thomas M. Klapötke,* Frank Mieskes, Jörg Stierstorfer, and
Michael Weyrauther[
a]
Abstract: 3-(Picrylamino)-1,2,4-triazole (PATO) and 3-amino-5- tinuclear NMR, IR, and Raman spectroscopy as well as mass
(
picrylamino)-1,2,4-triazole (APATO) were synthesized and ana- spectrometry. The low-temperature structures of two com-
lyzed. During the syntheses of the compounds, two interesting pounds were determined by single-crystal X-ray diffraction. The
side-products were isolated. The reactions of PATO and APATO thermal stabilities were measured by differential scanning calor-
with different nitrogen-rich bases, such as ammonia, hydrazine, imetry (DSC). The sensitivities were determined through the
triethylamine, and triaminoguanidine, resulted in the deproto- BAM drophammer and friction tests. The heats of formation
nation of both triazole compounds and the formation of the were calculated by the atomization method from the CBS-4M
corresponding salts (cation/anion ratio = 1:1). The compounds enthalpies and the densities determined by X-ray diffraction or
were obtained at ambient temperature in H O or EtOH as quali- pycnometry. Several detonation parameters including the deto-
2
tatively pure products with the characteristic properties of sec- nation pressure, detonation velocity, detonation energy, and
ondary explosives. The compounds were characterized by mul- detonation temperature were computed with the EXPLO5 code.
Introduction
methods.[7,8] Picryl chloride (2) was synthesized from picric acid
[
9]
[
1]
according to the literature method. Picryl chloride was then
reacted with 3-amino-1,2,4-triazole and 3,5-diamino-1,2,4-tri-
azole in N,N-dimethylformamide (DMF) to afford 3 and 13, re-
spectively. Furthermore, the side-product 4 could be identified
by XRD and NMR spectroscopy. Another side-product 14 could
by identified by XRD, but the structure could not be solved
properly so it is not discussed here. The reactions of 3 and 13
with bases resulted in the formation of salts containing the an-
ions of 3-(picrylamino)-1,2,4-triazole and 3-amino-5-(picryl-
Hexanitrostilbene (HNS) was developed by Shipp in 1964 by
treating trinitrotoluene (TNT) with sodium hypochlorite and is
one of the most commonly used explosives with a high thermal
stability. The most characteristic aspect of highly thermally sta-
ble explosives is a high decomposition point in the range 300–
400 °C. Therefore, HNS is used in space exploration, for example,
[
2–4]
as well as for drilling deep oil wells.
With the synthesis of
2,6-bis(picrylamino)-3,5-dinitropyridine (PYX), another interest-
ing and highly thermally stable explosive was developed by
1
13
[
5,6]
amino)-1,2,4-triazole. All compounds were analyzed by H, C,
Coburn in 1972.
Before this, Coburn synthesized two other
1
4
and N NMR spectroscopy; mass spectrometry; Raman and IR
spectroscopy; and elemental analysis.
interesting highly thermally stable explosives, namely, 3-(picryl-
amino)-1,2,4-triazole (PATO) and 3-amino-5-(picrylamino)-1,2,4-
[
7,8]
The eight different salts (shown in Scheme 1) of 3 that were
synthesized were the potassium (5), sodium (6), guanidinium
triazole (APATO).
These compounds consist of a nitrobenz-
ene ring and a triazole ring, both of which are typical building
blocks for explosives. To increase the thermal stability of explo-
sives, the formation of salts is a suitable strategy. In this paper,
we describe investigations of PATO (3), APATO (13), and the
formation of salts based on both compounds (Scheme 1).
(
(
7), aminoguanidinium (8), ammonium (9), triethylammonium
10), hydrazinium (11), and triaminoguanidinium (12) salts. The
four different salts of 13 that were synthesized were the potas-
sium (15), guanidinium (16), aminoguanidinium (17), and tri-
ethylammonium (18) salts.
Salts 5, 6, 9–11, 15, and 18 were synthesized from the free
bases or the corresponding hydroxides in water, aqueous eth-
anol, or methanol solution. Salts 7, 8, 16, and 17 were synthe-
sized from the corresponding carbonates and hydrogen carbon-
ates. Salt 12 was synthesized by a metathesis reactions with the
respective halide.
Results and Discussion
Syntheses
3
1
-(Picrylamino)-1,2,4-triazole (3) and 3-amino-5-(picrylamino)-
,2,4-triazole (13) were synthesized according to the literature
[
a] Department of Chemistry, Ludwig-Maximilian University of Munich,
Butenandtstraße 5–13 (D), 81377 München, Germany
E-mail: tmk@cup.uni-muenchen.de
Crystal Structures
http://www.hedm.cup.uni-muenchen.de/index.html
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/ejic.201501435.
The crystal structures of 4 and 7 were determined by X-ray
diffraction (Figures 1 and 2).
Eur. J. Inorg. Chem. 2016, 956–962
956
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
Scheme 1. Synthesis of ionic (picrylamino)-1,2,4-triazole derivatives under different reaction conditions: (a) KOH, EtOH, 3 h, reflux; (b) NaOH, EtOH, 3 h, 70 °C;
(
c) guanidinium carbonate, EtOH, 1 h, 70 °C; (d) aminoguanidinium hydrogen carbonate, EtOH, 3 h, 70 °C; (e) aqueous NH
3
, EtOH, 3 h, room temp.; (f)
triethylamine (TEA), EtOH, 2 h, 100 °C; (g) hydrazinium hydrate, EtOH, 3 h, r.t.; (h) triaminoguanidinium chloride, EtOH, 3 h, reflux; (i) KOH, EtOH, 3 h, 100 °C;
(
j) guanidinium carbonate, EtOH, 3 h, 100 °C; (k) aminoguanidinium hydrogen carbonate, MeOH, 3 h, 100 °C; (l) TEA, EtOH, 3 h, 100 °C.
Both structures show similar bond lengths and angles. In
each structure, the picryl moieties are twisted with respect to
the triazole ring plane (Figure 1).
Compound 4 includes one molecule of DMF in the structure
and crystalizes in the triclinic space group P 1¯ with two formula
units in the cell and a density of 1.557 g cm– at –100 °C.
Salt 7 crystallizes in the monoclinic space group C2/c with
eight formula units in the cell and a density of 1.697 g cm–3 at
3
–
100 °C.
From Equation (1), an average coefficient of volume expan-
sion α
of 1.42 × 10–
4
K
–1
was calculated for 7 to calculate its
Figure 1. Molecular structure of 4. Thermal ellipsoids are drawn at the 50 %
probability level.
v
density at room temperature. This value is similar to those of
other energetic materials such as hexogen (1.6 × 10– K ).
4
–1 [10]
ρ298K = ρ /[1 + α (298 – T )]
(1)
T
v
0
NMR Spectroscopy
The 1H, 13C, and 14N NMR spectra of 3–13 and 15–18 in
[
D ]dimethyl sulfoxide ([D ]DMSO) were recorded at room tem-
6
6
perature. The resonance for the carbon atom of the picryl moi-
ety next to the bridging nitrogen atom is observed at δ =
1
36.0 ppm for the neutral compound 3, whereas the signal is
observed at δ = 128.7 ppm for the side-product 4. For 13, the
signal for same carbon atom is observed at δ = 130.1 ppm. For
3, the signal for the carbon atom of the triazole moiety next to
the bridging nitrogen atom is observed at δ = 157.9 ppm,
whereas this signal is located at δ = 153.9 ppm for 13. The
signals for the carbon atoms in the picryl moieties in the corre-
sponding salts are shifted slightly to higher fields (δ = 135.8–
125.7 ppm) compared with those of 3. This signal is shifted to
Figure 2. Molecular structure of 7. Thermal ellipsoids are drawn at the 50 %
probability level.
Eur. J. Inorg. Chem. 2016, 956–962
www.eurjic.org
957
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
lower field for 6 only (δ = 141.4 ppm). The signals for the The other salts decompose in the range 195–317 °C. Compound
carbon atoms of the triazole moieties are observed at δ = 13 decomposes at 261 °C. With a decomposition point of
161.3–155.7 ppm. The signals for the carbon atoms in the picryl 145 °C, compound 17 exhibits the lowest decomposition point
moieties of the corresponding salts of 13 are shifted to low of all of the investigated salts of 13. The other salts decompose
field (δ = 142.7–140.2 ppm) compared with those of 13. The in the range 205–266 °C. A decomposition temperature of over
signals for the carbon atoms of the triazole moieties are ob- 200 °C is the unofficial minimum threshold value for new mili-
1
served at δ = 159.5–148.2 ppm. In the H NMR spectra, the tary explosives.
signal for the protons of the picryl moiety of the neutral com-
pounds 3, 4, and 13 are located at δ ≈ 8.89 (3), 9.22 (4), and were explored.
The sensitivities of 3, 5–13, and 15–18 to impact and friction
[
12–16]
The neutral compounds 3 and 13 are as-
8.83 ppm (13). Salts 6, 7, and 9–12 show signals shifted slightly sumed as insensitive to friction (360 N) and insensitive (3) and
to higher field (δ = 8.86–8.40 ppm) compared with that of 3. sensitive (13) to impact (40 and 25 J) according to the UN
[
17]
For salt 8, the signal shows a shift to low field (δ = 9.34 ppm). guidelines. Salts 5–10, 12, and 15–18 are assumed as insen-
Salts 15–18 show a shift for the signals to high field (δ = 8.70– sitive (360 N) to friction, and 11 is declared as sensitive (288 N)
8.30 ppm) compared with that of 13. For the neutral com- to friction. Regarding their impact sensitivities, 7–10, 12, and
pounds 3 and 13, the broad signals for the N–H hydrogen 16–18 are classified as insensitive (40 J), compounds 5, 6 and
atoms of the bridging nitrogen atoms are located at δ = 10.45 11 are classified as sensitive (7–15 J), and 15 is very sensitive
and 11.81 ppm, respectively, and this signal is absent for the (3 J).
salts. Compound 4 shows a signal for the amine group at δ =
6
.94 ppm, whereas the amine group in 13 exhibits a signal at
14
Heat of Formation
δ = 6.28 ppm. In the N NMR spectra, the nitro groups can be
observed at δ ≈ –12 ppm, the NH groups are located at δ ≈
The heats of formation of the compounds were computed theo-
retically by using the Gaussian 09 program package.
tain very accurate energies, the enthalpies (H) were calculated
by the CBS-4M method. The enthalpies of the gas-phase species
M were computed according to the atomization energy
–
–
200 ppm, and the amino groups are observed at δ ≈
350 ppm.
[18]
To ob-
Sensitivities and Thermal Stability
[19–22]
method; Equation (2).
The thermal capacities of 3–18 were tested through differential
Δ H°
= H(M,298) – ΣH°(atoms,298) + ΣΔ H°
(atoms,298)
(2)
f
(g,M,298)
f
–1 [11]
scanning calorimetry (DSC) measurements (5 °C min ).
cursor 3 exhibits a melting point of 178 °C and a decomposition
temperature of 316 °C, which is slightly higher than that re- porting Information. The lattice enthalpies (U ) and lattice en-
Pre-
All single values from the calculations are given in the Sup-
L
[
7,8]
ported previously (310 °C).
Compound 4 instead exhibits a thalpies (ΔH ) were calculated from the corresponding molec-
L
substantially lower decomposition temperature of 306 °C. With ular volumes (taken from the low-temperature X-ray structures)
[
23,24]
a decomposition point of 143 °C, compound 11 exhibits the according to equations developed by Jenkins and Glasser.
lowest decomposition point of all of the investigated salts of 3. With these values, the gas-phase enthalpies were converted
Table 1. Energetic properties and calculated detonation parameters of 3, 7–10, and HNS.
HNS
PATO (3)
7
8
9
10
Formula
FW /g mol
IS /J[
C
14
H
6
N
6
O
12
C
8
H
5
N
7
O
6
C
354.2
40
360
n.d.
39.5
–76.8
240
1.666
197.5
648.5
9
H
10
N
10
O
6
C
9
H
11
N
11
O
6
C
312.2
40
360
n.d.
35.9
–71.7
270
1.84
245.9
875.2
8
H
8
N
8
O
6
14 20 8 6
C H N O
396.15
40
360
n.d.
–
1
450.1
295.17
40
360
369.26
40
360
a]
[27]
5
[
b]
[27]
FS /N
240
0.8
[
c]
ESD /J
n.d.
n.d.
[
d]
N /%
Ω /%
T
18.67
–67.6
320
1.74
78.2
33.22
–67.7
316
1.94
147.1
573.9
41.7
–75.8
209
1.80
303.4
915.6
28.3
–129.2
263
[
e]
Dec. /°C[
f]
[27]
–
3[g]
[27]
[7]
[p]
[q]
[q]
[q]
ρ /g cm
1.53
–1[h]
Δ
Δ
f
H
m
°/kJ mol
68.6
279.5
–
1[i]
f
U°/kJ kg
239.76
EXPLO5_601 values
–
1[j]
–
Δ
ExU°/kJ kg
5142
3676
243
7612
602
4608
3185
313
8477
624
4391
3037
211
7543
732
4619
3050
268
8302
742
4931
3247
289
8400
697
4148
2537
158
6937
716
[
k]
Tdet /K
[
l]
–
P
V
CJ /kbar
Det. /m s
1[m]
–1[n]
o
V /L kg
F /kJ kg
–1[o]
752
675
756
769
769
618
[
14]
1 of 6). [b] Friction sensitivity (BAM friction tester,[14] 1 of 6). [c] Electrostatic discharge device (OZM); n.d.: not
[
a] Impact sensitivity (BAM drophammer,
[
28]
determined. [d] Nitrogen content. [e] Oxygen balance. [f] Decomposition temperature from DSC (ꢀ = 5 °C). [g] From X-ray diffraction at 173 K or pycnometry
at 298 K. [h] Calculated (CBS-4M) heat of formation. [i] Energy of formation. [j] Energy of explosion. [k] Explosion temperature. [l] Detonation pressure. [m]
Detonation velocity. [n] Assuming only gaseous products. [o] Specific energy. [p] Recalculated to 298 K. [q] Measured by gas (He) pycnometry at 298 K.
Eur. J. Inorg. Chem. 2016, 956–962
www.eurjic.org
958
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
Table 2. Energetic properties and calculated detonation parameters of 11–13 and 16–18.
11
12
APATO (13)
16
17
18
Formula
FW /g mol
IS /J[
C
327.1
7
288
n.d.
38.5
–70.9
143
8
H
9
N
9
O
6
C
9
H
13
N
13
O
6
C
8
H
6
N
8
O
6
C
9
H
11
N
11
O
6
C
9
H
12
N
12
O
6
14 21 9 6
C H N O
411.16
40
360
n.d.
–
1
399.29
40
360
310.19
25
360
369.09
40
360
384.10
40
360
a]
[
b]
FS /N
[
c]
ESD /J
n.d.
n.d.
n.d.
n.d.
N /%[
d]
45.6
–74.1
195
1.59
512.4
36.12
–67.1
261
1.85
147.4
554.9
41.73
–75.8
205
1.59
154.8
513.1
43.74
–74.9
145
1.66
260.6
775.0
30.64
–126.4
266
[
e]
Ω /%
T
Dec. /°C[
f]
3[g]
–
[p]
[p]
[7]
[p]
[p]
[p]
ρ /g cm
1.62
386.9
1273.4
1.50
–1[h]
Δ
Δ
f
H
m
°/kJ mol
25.9
171.4
–
1[i]
f
U°/kJ kg
1382.6
EXPLO5_601 values:
–
1[j]
–
Δ
ExU°/kJ kg
5137
3462
220
7640
745
4850
3229
208
7597
782
4473
3142
278
8178
664
4173
2947
185
7209
753
4379
2989
214
7657
764
3933
2460
151
6802
731
[
k]
Tdet /K
[
l]
–
P
V
CJ /kbar
Det. /m s
1[m]
–1[n]
o
V /L kg
F /kJ kg
–1[o]
877
859
709
755
777
611
[
14]
1 of 6). [b] Friction sensitivity (BAM friction tester,[14] 1 of 6). [c] Electrostatic discharge device (OZM); n.d.: not
[
a] Impact sensitivity (BAM drophammer,
[
28]
determined. [d] Nitrogen content. [e] Oxygen balance. [f] Decomposition temperature from DSC (ꢀ = 5 °C). [g] From X-ray diffraction at 173 K or pycnometry
at 298 K. [h] Calculated (CBS-4M) heat of formation. [i] Energy of formation. [j] Energy of explosion. [k] Explosion temperature. [l] Detonation pressure. [m]
Detonation velocity. [n] Assuming only gaseous products. [o] Specific energy. [p] Measured by gas (He) pycnometry at 298 K.
into the solid-state (standard conditions) enthalpies of forma- The salts showed lower calculated values than those of the neu-
tion Δ H ° (Tables 1 and 2). Lastly, the standard molar enthal- tral compounds 3 and 13. Only compound 9 is in the range of
f
m
pies of formation (ΔH ) were used to calculate the molar solid- its neutral parent compound 3. Compounds 3, 8, 9, and 13
m
–1
state energies of formation (ΔU ) according to Equation (3); Δn even reached more than 8000 m s .
m
is the change in the number of moles of gaseous components.
ΔUm = ΔHm – ΔnRT
(3)
Conclusions
The compound with the highest heat of formation is 12
From this experimental and theoretical study, the following
conclusions can be drawn:
–
1
–1
(
(
512.4 kJ mol ), followed by 11 (386.9 kJ mol ) and 8
–
1
303.4 kJ mol ). All of the compounds were calculated to show
(1) The neutral compounds 3-(picrylamino)-1,2,4-triazole (3)
positive heats of formation (i.e., endothermic). In comparison,
the calculated heats of formation for 1,3,5-trinitroperhydro-
and 3-amino-5-(picrylamino)-1,2,4-triazole (13) as well as the
starting materials could be synthesized by a facile and inexpen-
sive method. Two interesting side-products could also be iden-
tified.
–1
1
,3,5-triazine (RDX) and HNS are 70.3 and 78.2 kJ mol , respec-
tively, by the same theoretical method.
(2) Eight different salts [potassium (5), sodium (6), guanidin-
ium (7), aminoguanidinium (8), ammonium (9), triethylammon-
ium (10), hydrazinium (11), and triaminoguanidinium (12)] of
Detonation Parameters
The detonation parameters were calculated by using the EX- 3-(picrylamino)-1,2,4-triazole were synthesized from 3 by depro-
[
25,26]
PLO5 V6.01 computer code.
The input for EXPLO needs the tonation, followed by metathesis reactions involving the potas-
sum formula, density, and heat of formation. The calculations sium or sodium salt with the corresponding nitrogen-rich hal-
were performed with the maximum densities obtained from ide.
the low-temperature (173 K) crystal structures recalculated to
(3) Four different salts [potassium (15), guanidinium (16),
room temperature (298 K) and the pycnometric measurements. aminoguanidinium (17), and triethylammonium (18)] of 3-
The most important properties of a high explosive are its amino-5-(picrylamino)-1,2,4-triazole were synthesized from 13
detonation velocity VDet, detonation pressure p , and energy by deprotonation.
CJ
of explosion Δ U°. The properties of the commonly used explo-
(4) The side-product 4 and salt 7 were characterized by sin-
Ex
sives TNT, HNS, and RDX were also calculated with the EXPLO5 gle-crystal X-ray diffraction. The side-product shows a density
V6.01 code [VDet = 7450 (TNT), 7612 (HNS), 8815 m s– (RDX); of 1.557 g cm , whereas the nitrogen-rich salt 7 exhibits a den-
1
–3
–3
p
= 234 (TNT), 243 (HNS), 352 kbar (RDX); Δ U° = –5261 sity of 1.697 g cm .
CJ
Ex
(
TNT), –5142 (HNS), –5734 kJ kg–1 (RDX)].
In terms of their detonation velocities, 3, 7, 8, 9, 11, 13, ties and decompose at temperatures below 300 °C (except 3).
and 17 reached the values for commonly used highly thermally (6) The impact and friction sensitivities of the precursors and
(5) The investigated compounds show similar thermal stabili-
stable secondary explosives such as HNS. Compounds 3, 8, 9, salts were determined. According to UN recommendations, 3,
and 13 even exceed the calculated detonation velocity of HNS. 5–10, 12, 13, and 15–18 are classified as insensitive to friction,
Eur. J. Inorg. Chem. 2016, 956–962
www.eurjic.org
959
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
and 11 is classified as sensitive to friction. Towards impact, 3, δ = –12 (1 N, NO
), –269 (2 N, NH) ppm. BAM impact sensitivity
test: 40 J. Friction sensitivity test: 360 N.
2
7
–10, 12, and 16–18 are classified as insensitive; 5, 6, and 13
are classified as sensitive; and 15 is classified as very sensitive.
Compound 4: Yield 560 mg (28 %), orange-brown solid. DSC
–
1
1
(
7) On the basis of the crystallographic or pycnometric densi- (5 °C min ): 306 °C (dec.). H NMR (400 MHz, [D ]DMSO, 25 °C): δ =
6
1
3
9
.22 (s, 2 H, CH), 7.66 (s, 1 H, CH), 6.94 (s, 2 H, NH ) ppm. C NMR
ties and calculated (all endothermic) enthalpies of formation,
several detonation parameters were calculated. Compounds 3,
2
(
101 MHz, [D ]DMSO, 25 °C): δ = δ = 162.8 (1 C, CNH ), 157.2 (1 C,
6
2
NCN), 147.5 (1 C, CNO ), 147.1 (2 C, CNO ), 128.7 (1 C, CN), 125.1 (2
2
2
8
, 9, and 13 show the highest detonation velocities (3:
C, CH) ppm. 14N NMR (29 MHz, [D ]DMSO, 25 °C): δ = –10 (1 N,
–
1
6
8477 m s ). Compounds 3, 8, 9, and 13 also exceed the value
NO ), –349 (1 N, NH ) ppm.
2
2
for the detonation pressure of HNS (243 kbar). With respect to
their performance data, 3, 8, 9, and 13 could be of interest
as explosives with high thermal stabilities. On the basis of its
decomposition temperature and calculated energetic proper-
ties, compound 3 seems to be most promising.
Guanidinium-3-(picrylamino)-1,2,4-triazole (7): 3-(Picrylamino)-
,2,4-triazole (415 mg, 1.4 mmol) was dissolved in EtOH (10 mL),
1
and guanidinium carbonate (127.1 mg, 0.71 mmol) was added. The
mixture was heated for 1 h at 70 °C. The mixture was cooled and
the solvent was evaporated to yield 7 as a dark red solid, yield
–
1
3
95.0 mg (1.11 mmol, 79 %). DSC (5 °C min ): 240 °C (dec.).
C H N O (354.24): calcd. C 30.52, H 2.85, N 39.54; found C 30.51,
9
10 10 6
H 3.06, N 38.77. IR (ATR): ν˜ = 3473 (w), 3408 (m), 3254 (m), 3202
Experimental Section
(
(
(
(
(
m), 3084 (w), 2806 (w). 2360 (w), 2341 (w), 1651 (s) 1607 (m), 1558
s), 1476 (m), 1427 (m), 1386 (w), 1363 (m), 1318 (s), 1247 (s), 1159
m), 1112 (m), 1077 (m), 1008 (w), 966 (w), 932 (m), 910 (m), 882
CAUTION! Although we had no problems in the synthesis and han-
dling of the compounds described in this work, they are nevertheless
energetic materials with sensitivity to various stimuli. Proper protective
measures (face shield, ear protection, body armor, Kevlar gloves, and
earthed equipment) should be used at all times.
–1
w), 838 (w), 823 (w), 789 (m), 744 (m), 712 (s), 668 (w) cm . Raman
300 mW, 25 scans): ν = 3394 (2), 3264 (2), 3142 (2), 3082 (2),
˜
2
855 (2), 1803 (3), 1529 (57), 1500 (37), 1441 (7), 1339 (49), 1296
(
100), 1270 (93), 1187 (7), 1083 (7), 1010 (10), 976 (4), 944 (10), 870
The general procedures and analytical methods are described in
the Supporting Information. The values of the elemental analyses
differ slightly owing to the formation of adducts with variable num-
bers of solvent molecules. The experimental details for 5, 6, 8, 10–
(82), 821 (32), 741 (10), 713 (6), 532 (10), 496 (8), 458 (7), 338 (13),
–
1
+
2
39 (15), 117 (42) cm . MS (FAB+): m/z (%) = 60.1 (70) [CH N ] .
6 3
–
MS (FAB–): m/z (%) = 294.0 (100) [C H N O ] , 228.0 (10) [C H N O
–
C H N O ] , 122 (10) [C H N O – C H N O ] , 46 (7) [C H N O –
C H N O ] . H NMR (400 MHz, [D ]DMSO, 25 °C): δ = 12.77 (s, 1 H,
8
4
7
6
8 4 7 6
–
–
C H N ] , 199 (60) [C H N O – C H N O] , 151 (60) [C H N O –
2 2 3 8 4 7 6 2 2 4 8 4 7 6
12, 15, 17, and 18 can be found in the Supporting Information.
–
–
2
2
5
3
8
4
7
6
2
2
6
4
8 4 7 6
Picryl Chloride (2): Picryl chloride was prepared according to the
– 1
8
4
6
4
6
literature procedure.[
12]
13
NH), 8.40 (s, 2 H, CH), 7.42 (s, 1 H, CH), 6.90 (s, 6 H, NH ) ppm.
C
2
NMR (101 MHz, [D ]DMSO, 25 °C): δ = 160.0 (1 C, CNH ), 158.5 (1 C,
6
2
3
1
-(Picrylamino)-1,2,4-triazole (3) and 1-(2,4,6-Trinitrophenyl)-
H-1,2,4-triazol-3-amine (4): A mixture of 5-amino-1,2,4-triazole
CN), 149.5 (1 C, CH), 145.8 (2 C, CNO ), 141.4 (1C, CNO ), 125.8 (1
2
2
C, CN), 124.3 (2 C, CH) ppm. 14N NMR (29 MHz, [D ]DMSO, 25 °C,
6
(570.0 mg, 6.79 mmol) and picryl chloride (1.68 g, 6.79 mmol) in
ppm): δ = –14 (3 N, NO ), –187 (1 N, NH), –366 (1 N, NH ) ppm.
2
2
DMF (50 mL) was stirred for 5 h at 100 °C. The mixture was cooled
and poured into ice water, and the yellow solid was collected by
BAM impact sensitivity test: 40 J. Friction sensitivity test: 360 N.
filtration. The product mixture was dissolved in CHCl , and the solu-
Ammonium-3-(picrylamino)-1,2,4-triazole (9): 3-(Picrylamino)-
1,2,4-triazole (500 mg, 1.69 mmol) was dissolved in ethanol (10 mL),
and an aqueous ammonia solution (1.00 mL, 45.3 mmol, 25 % in
water) was added. The mixture was stirred for 3 h at room tempera-
ture and then cooled. The mixture was filtered, and the solvent was
removed. The product was obtained as a brown solid, yield
3
tion was filtered; product 3 was obtained as a bright yellow solid,
and product 4 remained in solution. After the evaporation of the
solvent, product 4 was obtained as light orange-brown solid, yield
(
total): 1.64 mg (82 %). C H N O (295.17): calcd. C 32.55, H 1.71, N
8 5 7 6
3
3.22; found C 32.75, H 1.75, N 33.45. IR [attenuated total reflec-
–
1
tance (ATR)]: ν˜ = 3443 (m), 3338 (m), 3250 (m), 3170 (m), 3139 (m),
323.0 mg (1.03 mmol, 64 %). DSC (5 °C min ): 270 °C (dec.).
C H N O (312.20): calcd. C 30.78, H 2.58, N 35.89; found C 31.73, H
3
1
1
1
087 (s), 2865 (m), 2360 (w), 2337 (w), 1858 (w), 1712 (w), 1697 (m),
8
8 8 6
644 (s), 1615 (s), 1592 (s), 1520 (vs), 1427 (s), 1401 (m), 1389 (m), 2.32, N 34.73. IR (ATR): ν = 3434 (m), 3321 (m), 3085 (w), 1620 (m),
˜
335 (vs), 1311 (s), 1292 (s), 1275 (s), 1254 (s), 1234 (vs), 1202 (s), 1591 (s), 1523 (vs), 1454 (m), 1419 (m), 1348 (s), 1269 (vs), 1235 (vs),
168 (s), 1092 (s), 1051 (m), 979 (s), 958 (m), 949 (m), 942 (m), 924
1163 (m), 1090 (m), 1044 (m), 980 (m), 933 (m), 898 (m), 828 (m),
–
1
(
(
s), 919 (s), 858 (s), 824 (m), 815 (m), 785 (m), 779 (m), 766 (m), 740
m), 732 (s), 717 (s), 712 (vs), 667 (s), 660 (s) cm . Raman (300 mW,
777 (m), 737 (s), 728 (s), 710 (s), 684 (m) cm . Raman (300 mW, 25
–
1
scans): ν = 1632 (15), 1530 (43), 1340 (100), 1167 (16), 1093 (6),
˜
–
1
2
1
5 scans): ν˜ = 2939 (5), 1621 (25), 1576 (13), 1548 (26), 1497 (8), 942 (13), 823 (21), 711 (6), 341 (10), 86 (40) cm . MS (FAB+): m/z
+
–
434 (6), 1402 (12), 1350 (100), 1315 (32), 1294 (33), 1206 (6), 1175 (%) = 18.1 (20) [NH ] . MS (FAB–): m/z (%) = 294.3 (89) [M] , 278
4
–
–
–
(13), 1094 (5), 1018 (3), 981 (4), 945 (10), 867 (5), 825 (17), 735 (4),
(25) [M – O] , 247 (13) [M – NO ] , 228 (22) [M – C H N ] , 212 (7)
2 2 2 3
–
–
1
6
63 (3), 393 (7), 337 (11), 290 (7), 238 (10), 202 (20), 161 (24), 96 [M – C H N ] , 46.1 (34) [M – C H N O ] . H NMR (400 MHz,
2 2 4 8 4 6 4
–1
(
2
57) cm . MS [desorption electron ionization (DEI+)]: m/z (%) = [D ]DMSO, 25 °C): δ = 9.05 (s, 2 H, CH), 8.86 (s, 1 H, CH), 8.26 (s, 1
6
+
+
+
13
95.2 (100) [M] , 249.2 (21) [M – NO ] , 229 (30) [M – C HN ] , 212 H, NH), 7.69 (br s, 4 H, NH ) ppm. C NMR (101 MHz, [D ]DMSO,
2
2
3
4
6
+
+
+
(30) [M – C H N ] , 203 (20) [M – (NO ) ] , 84 (16) [M – C O N ] .
25 °C): δ = 155.7 (1 C, CN), 145.1 (1 C, CH), 143.6 (2 C, CNO ), 140.3
2
2
3
4
2 2
6
6
3
(1 C, CNO
[D ]DMSO, 25 °C): δ = –15 (N, NO
), 134.2 (1 C, CN), 125.5 (2 C, CH) ppm. 14N NMR (29 MHz,
), –271 (N, NH), –364 (N, NH )
4
–
1
2
Compound 3: Yield 1.06 g (53 %), yellow solid. DSC (5 °C min ):
1
6
2
1
78 (m.p.), 316 °C (dec.). H NMR (400 MHz, [D ]DMSO, 25 °C): δ =
6
ppm. BAM impact sensitivity test: 40 J. Friction sensitivity test:
360 N.
1
3.83 (s, 1 H, NH), 10.45 (s, 1 H, NH), 8.89 (s, 2 H, CH), 8.35 (s, 1 H,
13
C H) ppm. C NMR (101 MHz, [D ]DMSO, 25 °C): δ = 157.9 (1 C,
6
CN), 144.0 (1 C, NCN), 140.4 (2 C, CNO ), 138.0 (1 C, CNO ), 136.0 (1
3-Amino-5-picrylamino-1,2,4-triazole (13): A mixture of 3,5-di-
amino-1,2,4-triazole (2.00 g, 20.2 mmol) and picryl chloride (5.00 g,
2
2
1
4
C, CNH), 126.6 (2 C, CH) ppm. N NMR (29 MHz, [D ]DMSO, 25 °C):
6
Eur. J. Inorg. Chem. 2016, 956–962
www.eurjic.org
960
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
2
0.2 mmol) in DMF (20 mL) was stirred for 5 h at 100 °C. The mixture search, Development and Engineering Center (ARDEC) under
was cooled and poured into ice water, and the orange solid was
collected by filtration. The product mixture was dissolved in eth-
anol, and the solution was filtered; product 13 was obtained as an
orange solid, and product 14 remained in solution, yield 3.65 g
grant number W911NF-12-1-0467, and the Office of Naval Re-
search (ONR) under grant numbers ONR.N00014-10-1-0535 and
ONR.N00014-12-1-0538 is gratefully acknowledged. The authors
acknowledge collaborations with Dr. Mila Krupka (OZM Re-
search, Czech Republic) in the development of new testing and
evaluation methods for energetic materials and with Dr. Mu-
hamed Suceska (Brodarski Institute, Croatia) in the develop-
–
1
(
11.7 mmol, 58 %). DSC: (5 °C min ): 261 °C (dec.). C H N O
8 6 8 6
(310.19): calcd. C 30.98, H 1.95, N 36.12; found C 30.40, H 2.14, N
3
1
1
1
7
2
1
8
9
6.20. IR (ATR): ν˜ = 3471 (w), 3389 (w), 3265 (vw), 3090 (w), 2094 (m),
675 (w), 1624 (m), 1575 (m), 1553 (m), 1534 (s), 1515 (vs), 1449 (w),
411 (w), 1395 (w), 1347 (vs), 1297 (m), 1284 (m), 1174 (w), ment of new computational codes to predict the detonation
096 (vw), 1082 (m), 927 (m), 863 (vw), 829 (vw), 756 (w), 734 (s), and propulsion parameters of novel explosives. The authors are
–
1
18 (m) cm . Raman (300 mW, 25 scans): ν = 3088 (6), 2218 (5), indebted to and thank Drs. Betsy M. Rice and Brad Forch (ARL,
˜
124 (5), 1623 (27), 1583 (12), 1556 (27), 1540 (27), 1397 (11),
Aberdeen, Proving Ground, MD) for many inspired discussions.
351 (100), 1300 (56), 1283 (40), 1175 (23), 1086 (9), 946 (17),
Stefan Huber is thanked for the sensitivity measurements.
30 (30), 735 (8), 375 (26), 337 (33), 278 (28), 205 (47), 121 (90),
–
1
+
2 (92) cm . MS (DEI+): m/z (%) = 310.1 (10) [M] , 264.1 (10) [M –
+
+
+
Keywords: Explosives · Energetic materials · Nitrogen
heterocycles · Calorimetry · Heats of formation
NO ] , 228.0 (90) [M – C H N ] , 213.1 (80) [M – C H N ] , 198.3
2
2
3
4
2 3 5
+
+
(45) [M – C H N O] , 136.1 (14) [M – C H N O ] , 120.1 (20) [M –
2 3 5 2 3 6 4
+
+
+
C H N O ] , 73.1 (90) [M – C H N O ] , 44.1 (60) [M – C H N O ] .
2
2
7
4
2
4
8
4
8 6 7 4
1
H NMR (400 MHz, [D ]DMSO, 25 °C): δ = 11.81 (br s, 1 H, NH), 10.21
6
[
[
1] K. G. Shipp, L. A. Kaplan, J. Org. Chem. 1966, 31, 857–861.
2] E. E. Kilmer, J. Spacecr. Rockets 1968, 5, 1216–19.
13
(br s, 1 H, NH), 8.83 (s, 2 H, CH), 6.28 (br s, 2 H, NH ) ppm. C NMR
2
(
101 MHz, [D ]DMSO, 25 °C): δ = 160.7 (1 C, CNH ), 153.9 (1 C, CN),
6
2
[3] T. Rieckmann, S. Volker, L. Lichtblau, R. Schirra, Chem. Eng. Sci. 2001, 56,
1327–1335.
[4] A. K. Sikder, N. Sikder, J. Hazard. Mater. 2004, 112, 1–15.
[5] M. D. Coburn, US 3678061, 1972.
1
42.6 (2 C, CNO ), 139.8 (1 C, CNO ), 130.1 (1 C, CN), 125.7 (2 C, CH)
2 2
14
ppm. N NMR (29 MHz, [D ]DMSO, 25 °C, ppm): δ = –9 (3 N, NO ),
6
2
–
235 (2 N, NH), –322 (1 N, NH ) ppm. BAM impact sensitivity test:
2
[
[
6] M. D. Coburn, United States Atomic Energy Commission, 1972, p. 2.
7] M. D. Coburn, T. E. Jackson, J. Heterocycl. Chem. 1968, 5, 199–203.
2
5 J. Friction sensitivity test: 360 N.
Guanidinium-3-amino-5-picrylamino-1,2,4-triazole
(16):
3-
[8] M. D. Coburn, United States Atomic Energy Commission, 1969, p. 1.
[9] K. C. Brown, M. El-Bermani, J. A. Weil, Spectrochim. Acta Part A 2010, 75,
381–388.
Amino-5-picrylamino-1,2,4-triazole (13) (420.0 mg, 1.35 mmol) was
dissolved in ethanol (10 mL), and guanidinium carbonate
[
10] C. Xue, J. Sun, B. Kang, Y. Liu, X. Liu, G. Song, Q. Xue, Propellants Explos.
Pyrotech. 2010, 35, 333–338.
(243.96 mg, 1.35 mmol) was added. The mixture was stirred for 3 h
at 100 °C and then cooled and filtered. After the evaporation of the
[
[
11] http://www.linseis.com (15.10.2015).
12] NATO Standardization Agreement (STANAG) on Explosives, Impact Sensi-
tivity tests, no. 4489, 1st ed., 1999.
solvent, 16 was obtained as a dark red solid, yield 476 mg
–
1
(
1.29 mmol, 95 %). DSC (5 °C min ): 205 °C (dec.). C H N O
8 5 7 6
(
3
369.25): calcd. C 29.27, H 3.00, N 41.73; found C 27.69, H 3.79, N
9.64. C H N O ·H O: calcd. C 27.91, H 3.38, N 39.78; found C 27.69,
[
13] WIWEB-Standardarbeitsanweisung, Nr. 4-5.1.02, Ermittlung der Explosions-
gefährlichkeit (impact sensitivity tests with a drophammer), Nov. 8, 2002.
8
5
7
6
2
H 3.79, N 39.64. IR (ATR): ν = 3329 (m), 3090 (m), 2770 (m), 1656 (s),
[14] a) http://www.bam.de; b) www.reichel&partner.de.
[15] NATO Standardization Agreement (STANAG) on Explosives, Friction Sensitiv-
ity Tests, no. 4487, 1st ed., 2002.
˜
1
(
601 (m), 1536 (s), 1427 (w), 1380 (m), 1343 (vs), 1256 (vs), 1164
–
1
vs), 1077 (s), 918 (M), 879 (m), 801 (S), 737 (m), 718 (s), 665 (s) cm .
[
16] WIWEB-Standardarbeitsanweisung, Nr. 4-5.1.03, Ermittlung der Explosions-
gefährlichkeit or der Reibeempfindlichkeit mit dem Reibeapparat, Nov. 8,
Raman (300 mW, 25 scans): ν = 3091 (2), 2116 (2), 1542 (64), 1486
˜
(
30), 1341 (72), 1306 (87), 1279 (100), 1167 (14), 1083 (13), 1009 (8),
2002.
9
49 (12), 868 (4), 823 (55), 727 (17), 507 (12), 390 (10), 328 (6), 229
[
17] Impact: insensitive: 40 J, less sensitive: ca. 35 J, sensitive: ca. 4 J, very
sensitive: ca. 3 J. Friction: insensitive: >360 N, less sensitive: ca. 360 N,
sensitive: <360 N, very sensitive: >80 N, extremely sensitive: >10 N. Ac-
cording to the UN Recommendations on the Transport of Dangerous
Goods, (+) indicates “Not safe for transport”.
–1
+
(11), 97 (39) cm . MS (FAB+): m/z (%) = 60.1 (22) [guanidinium] .
–
–
MS (FAB–): m/z (%) = 309.1 (26) [M] , 228.0 (10) [M – C H N ] , 199.3
2
3 4
–
–
(45) [M – C H N O] , 168.2 (50) [M – C HN O ] , 153.2 (50) [M –
2 3 5 2 5 3
–
–
– 1
C HN O ] , 122 (22) [M – C H N O ] , 46 (38) [M – C H N O ] . H
2
6
3
2
3
7
4
8 5 7 4
NMR (400 MHz, [D ]DMSO, 25 °C): δ = 8.68 (br s, 1 H, NH), 8.35 (s,
[18] M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R.
Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G. A. Petersson, H. Nak-
atsuji, M. Caricato, X. Li, H. P. Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng,
J. L. Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa,
M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, J. A. Mont-
gomery Jr., J. E. Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers,
K. N. Kudin, V. N. Staroverov, R. Kobayashi, J. Normand, K. Raghavachari,
A. Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J. M.
Millam, M. Klene, J. E. Knox, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo,
R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli,
J. W. Ochterski, R. L. Martin, K. Morokuma, V. G. Zakrzewski, G. A. Voth,
P. Salvador, J. J. Dannenberg, S. Dapprich, A. D. Daniels, Ö. Farkas, J. B.
Foresman, J. V. Ortiz, J. Cioslowski, D. J. Fox, Gaussian 09, revision A.02,
Gaussian, Inc., Wallingford CT, 2009.
6
13
2
H, CH), 7.29 (br s, 6 H, NH ), 4.96 (br s, 2 H, NH ) ppm. C NMR
2
2
(
101 MHz, [D ]DMSO, 25 °C): δ = 162.8 (1 C, CNH ), 159.5 (1 C, CN),
6
2
1
58.4 (1 C, CNH ), 144.5 (2 C, CNO ), 142.7 (1 C, CN), 141.1 (1 C,
2 2
1
4
CNO ), 124.2 (1 C, CH) ppm. N NMR (29 MHz, [D ]DMSO, 25 °C):
2
6
δ = –15 (3 N, NO ), –181 (1 N, NH), –370 (4 N, NH ) ppm. BAM
2
2
impact sensitivity test: 40 J. Friction sensitivity test: 360 N.
CCDC 1433585 (for 4·DMF) and 1433586 (for 7) contain the supple-
mentary crystallographic data for this paper. These data can be ob-
tained free of charge from The Cambridge Crystallographic Data
Centre.
[
[
19] E. F. C. Byrd, B. M. Rice, J. Phys. Chem. A 2006, 110, 1005–1013.
20] L. A. Curtiss, K. Raghavachari, P. C. Redfern, J. Pople, J. Chem. Phys. 1997,
Acknowledgments
1
06, 1063–1079.
Financial support of this work by the Ludwig-Maximilian Univer-
sity of Munich (LMU), the U.S. Army Research Laboratory (ARL)
under grant number W911NF-09-2-0018, the Armament Re-
[
[
21] B. M. Rice, S. V. Pai, J. Hare, Combust. Flame 1999, 118, 445–458.
22] T. Altenburg, T. M. Klapoetke, A. Penger, J. Stierstorfer, Z. Anorg. Allg.
Chem. 2010, 636, 463–471.
Eur. J. Inorg. Chem. 2016, 956–962
www.eurjic.org
961
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
[
23] H. D. B. Jenkins, H. K. Roobottom, J. Passmore, L. Glasser, Inorg. Chem.
999, 38, 3609–3620.
[28] a)
http://www.ozm.cz/testing-instruments/smallscaleelectrostatic-
1
discharge-tester.htm; b) V. Pelik, OZM research, Czech Republic, private
communication.
[24] H. D. B. Jenkins, D. Tudela, L. Glasser, Inorg. Chem. 2002, 41, 2364–2367.
[25] M. Suceska, Propellants Explos. Pyrotech. 1991, 16, 197–202.
[26] M. Sućeska, EXPLO5, v. 6.01, Brodarski Institute, Zagreb, Croatia, 2013.
[27] R. Meyer, J. Köhler, A. Homburg, Explosives, Wiley-VCH, Weinheim, Ger-
many, 2008.
Received: December 10, 2015
Published Online: January 27, 2016
Eur. J. Inorg. Chem. 2016, 956–962
www.eurjic.org
962
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim