A study of cyanotetrazole oxides and derivatives thereof

Article abstract of DOI:10.1002/asia.201200903

In this work we report on the syntheses of energetic salts of cyanotetrazolate-1- and -2-oxides; this offers a unique ability to compare the effects of tetrazole 1- versus 2-oxidation. 5-Cyanotetrazolate-2-oxide can be synthesized by oxidation of the 5-cyanotetrazolate anion with Oxone, while the corresponding 1-oxide was synthesized by the rearrangement of azidoaminofurazan. Both chemical (multinuclear NMR, IR, and Raman spectroscopies, mass spectrometry, etc.) as well as explosive (impact, friction, and static sensitivities) properties are reported for these energetic salts. Calculated explosive performances using the EXPLO5 computer code are also reported. We furthermore detail the chemistry of these two anions, and their ability to form tetrazole-carboxamides, dihydrotetrazines, and tetrazines. The ability to hydrolyze cyanotetrazole oxides to their amides was demonstrated by two copper complexes. Several crystal structures of these species are presented in addition to full chemical characterization. Finally, the unique 1,4,-bis(2-N- oxidotetrazolate)-1,2,4,5-tetrazine anion was characterized as an energetic material as its ammonium salt. Copyright

Full text of DOI:10.1002/asia.201200903

FULL PAPER
DOI: 10.1002/asia.201200903
A Study of Cyanotetrazole Oxides and Derivatives thereof
Franziska Boneberg, Angie Kirchner, Thomas M. Klapçtke,* Davin G. Piercey,
Maximilian J. Poller, and Jçrg Stierstorfer[a]
Abstract: In this work we report on the
syntheses of energetic salts of cyanote-
trazolate-1- and -2-oxides; this offers
a unique ability to compare the effects
of tetrazole 1- versus 2-oxidation. 5-Cy-
anotetrazolate-2-oxide can be synthe-
sized by oxidation of the 5-cyanotetra-
zolate anion with Oxone, while the cor-
responding 1-oxide was synthesized by
the rearrangement of azidoaminofura-
zan. Both chemical (multinuclear
NMR, IR, and Raman spectroscopies,
mass spectrometry, etc.) as well as ex-
plosive (impact, friction, and static sen-
sitivities) properties are reported for
these energetic salts. Calculated explo-
sive performances using the EXPLO5
computer code are also reported. We
furthermore detail the chemistry of
these two anions, and their ability to
form tetrazole-carboxamides, dihydro-
tetrazines, and tetrazines. The ability to
hydrolyze cyanotetrazole oxides to
their amides was demonstrated by two
copper complexes. Several crystal
structures of these species are present-
ed in addition to full chemical charac-
terization. Finally, the unique 1,4,-
bis(2-N-oxidotetrazolate)-1,2,4,5-tetra-
zine anion was characterized as an en-
ergetic material as its ammonium salt.
Keywords: crystal structures · ener-
getic materials · N-oxides · tetra-
zines · tetrazoles
Introduction
compounds is the addition of a zwitterionic N-oxide to the
nitrogen system. The removal of s electron density can sta-
bilize systems as is seen in 1,2,3,4-tetrazine dioxides,[13–15]
and N-oxides also increase densities[16] and oxygen balances,
thus leading to increased energetic performances. Addition-
ally, the increased intermolecular interactions afforded by
the very polar N-oxide often stabilize these materials to-
wards physical impact, thereby making them safer to
handle.[17,18] The utility of N-oxides is illustrated in the varie-
ty of energetic materials possessing this functionality such as
5,7-dinitrobenzo-1,2,3,4-tetrazine-1,3-dioxide (DNBTDO),[19]
TKX50,[20] and dinitroazofuroxan (DDF)[21] (Figure 1).
The development of new energetic materials for practical
use is an area of intense research.[1–5] Many strategies in the
design of new energetic materials have been extensively ex-
plored, differing only in the source of energy content. Tradi-
tional energetic materials such as RDX (1,3,5-trinitro-1,3,5-
triazacyclohexane) and TNT (2,4,6-trinitrotoluene) rely on
the oxidation of a carbon backbone by oxygen present in
the molecule, ring- or caged-strained compounds such as oc-
tanitrocubane or trinitroazetidine, which introduce addition-
al energy content from their strained bonds and high heat of
formation, or nitrogen-rich compounds, for which the ener-
getic driving force originates from nitrogen–nitrogen double
and single bonds to produce nitrogen gas.
However, these energetic strategies have drawbacks: ni-
troaromatics and nitramines are toxic,[6,7] compounds with
excessive ring or cage strain have very long synthetic
routes,[8,9] and nitrogen-rich compounds lose thermodynamic
and mechanical stability as the number of nitrogen atoms
per heterocycle or chain becomes too large.[10,11,12] A possi-
ble solution to the problem of stability of very nitrogen-rich
Figure 1. Energetic N-oxides.
[a] F. Boneberg, A. Kirchner, Prof. Dr. T. M. Klapçtke, D. G. Piercey,
M. J. Poller, J. Stierstorfer
Within the area of tetrazole-N-oxides we have previously
detailed the preparation of salts of nitro-,[17] azido-,[18] and
bistetrazole[20] oxides, and the general trends for N-oxides
have held true; they are of higher density, lower sensitivity,
and higher performance than the non-oxidized parent com-
pounds; however, they possess a slightly lowered thermal
stability. We have been limited previously by the lack of an
easy comparison between 1- and 2-tetrazole oxides as nitro-
Department of Chemistry
Energetic Materials Research
Ludwig-Maximilian University
Butenandtstr. 5–13 (D), 81377 Mꢀnchen (Germany)
Fax : (+49)89-2180-77492
E-mail: tmk@cup.uni-muenchen.de
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/asia.201200903.
Chem. Asian J. 2013, 8, 148 – 159
148
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
and azidotetrazole are known as their 2-oxides, whereas bis-
tetrazole is known as its 1-oxide. In this work, we detail the
preparation and characterization of both salts of cyanotetra-
zole 1- and 2-oxides, thereby allowing for the comparison of
the effect of N1- versus N2-oxidation. Additionally, we
report on the reactions of cyanotetrazole oxides to give tet-
razole oxides functionalized with carboxamide, 1,4-dihydro-
1,2,4,5-tetrazines, and 1,2,4,5 tetrazine.
rich salts (aminoguanidinium cyanotetrazolate-2-oxide (5),
diaminoguanidinium cyanotetrazolate-2-oxide (6), triamino-
guanidinium cyanotetrazolate-2-oxide (7), aminoguanidini-
um cyanotetrazolate-1-oxide (8), and triaminoguanidinium
cyanotetrazolate-1-oxide (9)) of the cyanotetrazolate-1 and
-2 oxides after filtering off the corresponding silver halide as
by-product. Crystals were grown by the slow diffusion of
ether into a methanolic solution of the salt.
When copper(II) chloride was attempted to be reacted
with silver salts 1 and 3, instead of obtaining the desired salt
of cyanotetrazolate oxide, the cyano group of the tetrazole
was found to hydrolyze to the amide, thus yielding the
copper salts of the carboxamidetetrazole oxides as the dihy-
drates (Scheme 3). These salts, unlike the other salts, were
heated during synthesis, and we suspect that this is the
reason for hydrolysis. The hydrolysis of cyanoazoles in aque-
ous media has been observed previously.[23]
Results and Discussion
Synthesis
Prior to this work, the cyanotetrazolate-2-oxide anion was
unknown. The preparation of the cyanotetrazolate-2-oxide
anion was based on an extrapolation of our previous
work.[17,18] An aqueous solution of sodium 5-cyanotetrazo-
late was oxidized with potassium peroxymonopersulfate
(Oxone) overnight at 408C (Scheme 1). By pouring the reac-
Scheme 1. Oxidation of the cyanotetrazolate anion.
Scheme 3. Hydrolysis of cyanotetrazole oxides to their amides.
tion mixture into acetone and filtering the precipitate,
a crude solution of the cyanotetrazolate-2-oxide in acetone
was obtained. After purification by recrystallization, the
crude cyanotetrazolate-2-oxide salts were precipitated with
silver nitrate, thus yielding pure silver cyanotetrazolate-2-
oxide (1) as a white powder. In the case of the ammonium
salt (2), extraction of the crude reaction mixture with ethyl
acetate after the addition of aqueous sodium tributylammo-
nium sulfate yielded the tributylammonium salt. Ion ex-
change led to the isolation of ammonium cyanotetrazolate-
2-oxide (2) as colorless crystals.
It is known in the literature[24] that upon treatment of 5-
cyanotetrazole with hydrazine in ethanol, a dihydrotetrazine
is formed, thereby bridging the tetrazole rings. When cyano-
tetrazole 1- and 2-oxides were protonated with nitric acid
yielding 5-cyano-2-hydroxytetrazole and 5-cyano-1-hydroxy-
tetrazole, the subsequent treatment with hydrazine gave the
corresponding dihydrotetrazines as their hydrazinium salts
(12, 13; see Scheme 4).
Unlike the cyanotetrazolate-2-oxide, the cyanotetrazolate-
1-oxide anion has been reported in one study[22] as the
sodium salt from the reaction of azidoaminofurazan with
sodium nitrite (Scheme 2). This sodium salt was precipitated
as the silver salt (3) by addition of aqueous silver nitrate, or
transformed to the ammonium salt (4) by ion exchange
chromatography performed after extracting the tributylam-
monium salt from solution.
Compounds 12 and 13 were then protonated with hydro-
chloric acid in water yielding the 1- and 2-hydroxy species
as hydrates, 14·2H2O and 15·H2O. Determination of hydra-
tion waters was based on ꢂbest fitꢃ of the elemental analyses.
14·2H2O and 15·H2O were then deprotonated with ammonia
yielding ammonium salts 16 and 17·H2O, respectively. With
Using silver salts 1 and 3, metathesis reactions with ami-
noguanidinium chloride, diaminoguanidinium iodide, or tria-
minoguanidinium chloride gave the corresponding nitrogen-
Scheme 2. Rearrangement of azidoaminofurazane to the cyanotetrazo-
late-1-oxide anion.
Scheme 4. Formation of dihydrotetrazines.
Chem. Asian J. 2013, 8, 148 – 159
149
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
the free dihydrotetrazines 14·2H2O and 15·H2O in hand, the
goal was to oxidize them to the corresponding tetrazines
(Scheme 5).
trazine, respectively. After oxidation of the dihydrotetrazine
tetrazole-2-oxide and formation of the ammonium salt 20,
the carbon resonances are found at 158.2 and 150.9 ppm.
15NNMR spectroscopy was also performed, and the assign-
ment of resonances was made based on a calculated spec-
trum using MPW1PW91/aug-cc-pVDZ, Gaussian 09.[25] All
resonances were readily assigned with the exception of N2
and N3 in the cyanotetrazolate-2-oxide anion, for which the
resonances were too similar to assign them with certainty.
Assignments are presented in Figure 2.
Scheme 5. Oxidation of dihydrotetrazines to tetrazines.
Initially, 18 was prepared by bubbling NO2 through an
aqueous solution of 14·2H2O. The solution instantly turned
deep red due to formation of the tetrazine; however, analy-
sis of the NMR spectra indicated extensive decomposition.
When a dilute solution of NO2 in acetonitrile was added to
a slurry of 14·2H2O in acetonitrile until no more solid dis-
solved, a product of higher purity was obtained. The
13CNMR spectrum only possessed two resonances, whereas
1
in the HNMR spectrum decomposition was still observed,
thus precluding assignment. After addition of the NO2 solu-
tion in acetonitrile, the remaining insolubles were filtered
off and the red filtrate was concentrated. Unfortunately, 18
proved to be hygroscopic, and therefore it was dried under
high vacuum at 408C. The obtained red material, when
freshly dried, was a highly sensitive explosive: it exploded
when a 150 g hammer impacted it from only 1 cm. By react-
ing this material with aqueous ammonia, the ammonium salt
20 was obtained and fully characterized. Crystals of 20 were
grown by diffusing ether into a methanolic solution of 20.
The oxidation of 15·H2O to 19 by a similar methodology
proved unsuccessful. Oxidation in a manner analogous to
that of the 2-oxide led to a red material that lost color upon
standing in MeOH or DMSO and decomposed. Attempts
using chlorine or ozone as oxidants also failed.
Figure 2. 15N NMR spectrum of cyanotetrazolate-1 and ꢀ2-oxides.
The IR and Raman spectra of all cyanotetrazolate oxide
salts were collected and assigned using frequency analysis
from an optimized structure of B3LYP/cc-pVDZ calcula-
tions using the Gaussian 09 software[25]. All calculations
were performed at the DFT level of theory; the gradient-
corrected hybrid three-parameter B3LYP[26,27] functional
theory was used with a correlation-consistent p-VDZ basis
set.[28–31]
In the IR spectra, the cyanotetrazolate-1-oxide salts gen-
erally contain a strong band around 1406 cmꢀ1. The calculat-
ed value for this band is 1503 cmꢀ1 and it arises from N O
ꢀ
ꢀ1
stretching. At 2247–2255 cmꢀ1 (calc. 2312 cm ), the C N
ꢁ
stretch is seen. At 1429 cmꢀ1 (calc. 1458 cmꢀ1), N1-C1-N4
symmetric tetrazole ring deformation occurs. Finally, the
N1-C1-N4 asymmetric tetrazole deformation with minor N-
O stretching occurs at 1241–1257 cmꢀ1 (calc. 1278 cmꢀ1).
Spectroscopy
Multinuclear NMR spectroscopy, especially 13C and
15NNMR spectroscopy proved to be a useful tool for the
characterization of the energetic anions and their salts. In
the case of the cyanotetrazolate-1- and 2-oxide anions, the
resonance of the tetrazole ring carbon was more downfield
for the 2-oxide at 131.1 ppm versus 123.7 ppm for the 1-
oxide. The cyano groups exhibit less of a shift difference,
with resonances at 112.3 ppm and 110.5 ppm for the 2-oxide
and the 1-oxide, respectively. When the cyano groups of
both compounds were cyclized to give salts of dihydrotetra-
zines (12, 13, 16, and 17), the 2-oxide possesses resonances
at 148.1 and 140.5 ppm and the 1-oxide at 140.4 and
134.3 ppm. Unfortunately, these resonances are too similar
to assign them to the tetrazole oxide and to the dihydrote-
The IR spectrum of the cyanotetrazolate-2-oxides possess-
ꢀ1
ꢀ
es an N O O stretch between 1430 and 1674 cm (calc.
ꢀ1
ꢀ1
ꢁ
1533 cm ). The C N stretch occurs at 2251–2259 cm (calc.
2315 cmꢀ1). Between 950 and 979 cmꢀ1 (calc. 950 cmꢀ1), the
tetrazole N2-N3 stretch is observed, and finally between
1133 and 1360 cmꢀ1 (calc. 1401 cmꢀ1), the N3-N4 stretch is
seen.
The Raman spectra of all salts of cyanotetrazolate-1-oxide
adopt a characteristic pattern of two bands of high intensity.
The band between 2249 and 2257 cmꢀ1 (calc. 2312 cmꢀ1) is
ꢁ
caused by C N stretching. The final stretching occurring at
1458–1465 cmꢀ1(calc. 1458 cmꢀ1) corresponds to a N1-C1-N4
symmetric tetrazole ring deformation.
Chem. Asian J. 2013, 8, 148 – 159
150
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
In the Raman spectra of the cyanotetrazolate-2-oxide
salts, a characteristic pattern of three diagnostic bands is ob-
served. The strongest band at 2256–2261 cmꢀ1(calc.
ꢀ1
ꢁ
2315 cm ) arises from the C N stretch. The second band
corresponds to a tetrazole N2-N3 stretch and occurs be-
tween 1001 and 1019 cmꢀ1 (calc. 950 cmꢀ1). The final diag-
nostic stretch ranging from 1436 to 1442 cmꢀ1 (calc.
1407 cmꢀ1) belongs to C1-N4 asymmetric tetrazole deforma-
tion.
Figure 4. Molecular unit of 4 and its labeling scheme. Ellipsoids are
drawn at the 50% probability level.
Single Crystal X-ray Analysis
Several herein described compounds (2, 4, 5, 6, 7, 9, 10, 11,
and 20) were also characterized by low-temperature single-
crystal X-ray diffraction. Selected data and parameters of
the measurements and solutions are gathered in Tables S1
and S2 in the Supporting Information.
oclinic in the space groups P21/n and P21/c, respectively. The
diaminoguanidinium salt 6 (1.534 gcmꢀ3) shows a slightly
higher density in comparison to 5 (1.504 gcmꢀ3). Both struc-
tures again are dominated by an intense hydrogen bond net-
work.
The structures of triaminoguanidinium 1- (9) and 2-oxido-
5-cyanotetrazolate (7) could also be determined. The triami-
noguanidinium cations follow structures published numer-
ously in the literature such as, for example, triaminoguanidi-
nium nitrate.[33] The densities of 1.550 gcmꢀ3 (7) and
1.583 gcmꢀ3 (9) are higher than those of 2 and 4–6. The mo-
lecular units of both structures are shown in Figures 7 and 8.
Ammonium 2-oxido-5-cyanotetrazolate (2) crystallizes in
the non-centrosymmetric space group Pca21 with four
cation/anion pairings in the unit cell. In comparison with the
corresponding ammonium 1-oxido-5-cyanotetrazolate (4)
(monoclinic, P21/c), 2 has a slightly higher density of
1.553 gcmꢀ3 (vs. 1.526 gcmꢀ3 for 4). Basically, the oxido-cya-
notetrazolate anions are formed as planar anions, in agree-
ment with non-oxidized 2H-cyanotetrazole.[32] Within the
planar aromatic tetrazolate rings, bond lengths between
single and double bonds are observed. The bond lengths be-
tween the cyano group and the C1 atom lie between 1.42
and 1.44 ꢄ, while the CN bond length in the cyano group is
between 1.13 and 1.15 ꢄ. These two bond lengths are not af-
fected by deprotonation as well as oxygenation of the tetra-
zole ring system. Detailed bond lengths and angles are gath-
ered in Table S3 in the Supporting Information.
The structures of 2 and 4 are dominated by several strong
hydrogen bonds involving all hydrogen atoms of the ammo-
nium cations coordinating to the atoms N2, N4, and O1 (2)
and N1, N2, N3, N4, and O1 (4), respectively. Depictions of
the molecular units are presented in Figures 3 and 4.
Amino- (5) and diaminoguanidinium 2-oxido-5-cyanote-
trazolate (6), shown in Figures 5 and 6, both crystallize mon-
Figure 5. Molecular unit of 5 and its labeling scheme. Ellipsoids are
drawn at the 50% probability level.
Figure 3. Molecular unit of 2 and its labeling scheme. Ellipsoids are
Figure 6. Molecular unit of 6 and its labeling scheme. Ellipsoids are
drawn at the 50% probability level.
drawn at the 50% probability level.
Chem. Asian J. 2013, 8, 148 – 159
151
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
Figure 7. Molecular unit of 7 and its labeling scheme. Ellipsoids are
drawn at the 50% probability level.
Figure 10. Molecular unit of 11 and its labeling scheme. Ellipsoids are
drawn at the 50% probability level. Selected bond lengths [ꢄ]: Cu1–O2
1.935(2), Cu1–O1 1.980(2), Cu1–O3 2.396(3), N5–C2 1.313(4), N4–C1
1.335(4), N4–N3 1.345(3), N3–N2 1.305(4), N2–N1 1.338(3), N1–O2
1.328(3), N1–C1 1.341(4), O1–C2 1.245(4), C2–C1 1.481(4); selected coor-
dination angles [8]: O2-Cu1-O1 94.62(9), O2-Cu1-O3 89.80(10), O1-Cu1-
O3 92.51(9).
nation sphere of complex 11 is a typical example of an elon-
gated octahedron formed by Jahn–Teller distortion and de-
scribed for several copper(II) tetrazolates in the litera-
ture.[34]
Compound 20 could only be obtained crystalline as its tri-
hydrate. A depiction of a molecular unit is given in
Figure 11. The asymmetric unit consists of two transected
Figure 8. Molecular unit of 9 and its labeling scheme. Ellipsoids are
drawn at the 50% probability level.
Single crystals could be obtained after the reaction of 1-
and 2-oxido-5-cyanotetrazolate with copper sulfate. In both
cases, the corresponding CuII complexes of the hydrolyzed
CN moiety were formed as dihydrates. In both compounds,
an expected distorted coordination sphere of d9 copper cen-
ters was observed; however, the coordination modes of the
oxido-tetrazolates were different. In the case of 10
(Figure 9), the bidentate coordination (5-membered ring) is
formed by the ring nitrogen atom N1 and the carboxy
oxygen atom O1. In the case of 11 (Figure 10), a six-mem-
bered ring is formed by coordination of the N-oxide oxygen
atom O2 as well as the carboxy oxgen atom O1. The coordi-
Figure 11. View on one molecular unit of 20 and its labeling scheme. El-
lipsoids are drawn at the 50% probability level.
dianions. All water and ammonium protons participate in
hydrogen bonds. The density of 20 (1.627 gcmꢀ3), which
ꢀ
crystallizes in the triclinic space group P1, is the highest ob-
served for the crystalline CHNO compounds within this
work. The oxido-tetrazolate dianions have a planar structure
similar to that of recently published energetic salts of the
3,6-bis(tetrazole-5-ylate)-1,2,4,5-tetrazine dianion.[35] The
dianions are orientated in bands connected by hydrogen
bonds involving crystal water and atom O4. Gaps are filled
with the ammonium cations and two further crystal water
molecules, as shown in Figure 12.
Figure 9. Molecular unit of 10 and its labeling scheme. Ellipsoids are
drawn at the 50% probability level. Selected bond lengths [ꢄ]: Cu1–N1
1.957(2), Cu1–O3 2.181(3), Cu1–O1 2.191(2), N1–N2 1.326(3), N1–C1
1.335(3), O2–N3 1.284(3), N3–N2 1.330(3), N3–N4 1.337(3), N5–C2
1.312(4), O1–C2 1.245(4), N4–C1 1.327(4), C1–C2 1.489(4); selected coor-
dination angles [8]: N1-Cu1-O3 90.65(10), N1-Cu1-O1 78.48(8), O3-Cu1-
O1 92.32(9).
Chem. Asian J. 2013, 8, 148 – 159
152
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
Table 1. CBS-4M results and gas-phase enthalpies
Formula
ꢀH298[a]/a.u.
DfH (g)[b] [kJmolꢀ1
]
HCT2X[c]
CT2Xꢀ[d]
HCT1X[e]
CT1Xꢀ[f]
TT2X2ꢀ[g]
C2HN5O
C2HN5Oꢀ
C2HN5Oꢀ
C2N5Oꢀ
425.116700
424.625696
425.105680
424.615667
958.510314
56.796608
260.701802
315.949896
371.197775
484.7
240.3
513.6
266.7
864.6
635.8
671.6
772.7
874.3
2ꢀ
C4N12O2
+[h]
+
NH4
NH4
AG +[i]
CH7N4
CH8N5
CH9N6
+
DAG+[j]
TAG +[k]
+
+
[a] CBS-4M enthalpy at room temperature; [b] calculated gas-phase heat
of formation by using the atomization equation; [c] cyanotetrazolate-2-
oxide, protonated; [d] cyanotetrazolate-2-oxide, deprotonated; [e] cyano-
tetrazolate-1-oxide, protonated; [f] cyanotetrazolate-1-oxide, deprotonat-
ed; [g] 1,4,-bis(2-N-oxidotetrazolate)-1,2,4,5-tetrazine; [h] ammonium;
[i] aminoguanidinium cation; [j] diaminoguanidinium cation; [k] triamino-
guanidinium cation.
Figure 12. View on the layer-like packing of 20. One unit cell is drawn.
Only these compounds were calculated as they have experi-
mental densities for energetic performance calculations.
With the calculated lattice enthalpy (Table 2), the gas-phase
enthalpy of formation was converted into the solid-state
(standard conditions) enthalpy of formation. These molar
standard enthalpies of formation (DHm) were used to calcu-
late the molar solid-state energies of formation (DUm) ac-
cording to Eq. 2 (Table 2).
Energetic Properties
Often, energetic materials tend to explode in bomb calori-
metric measurements. Consequently, doubtful combustion
energies can potentially be obtained. Therefore, heats of for-
mation of energetic materials are mostly calculated theoreti-
cally. In our group, we combine the atomization energy
method (Eq. 1) with CBS-4M electronic energies (Table 1),
which has been shown suitable in many recently published
studies.[36] CBS-4M energies of the atoms, cations, and
anions were calculated with the Gaussian 09 (revision A1)
software package[25] and checked for imaginary frequencies.
Values for DfH8 (atoms) were taken from the NIST data-
base.[37]
DUm ¼ DHmꢀDn RT
ð2Þ
in which Dn denotes the change of moles of gaseous com-
ponents.
Density is one of the most important parameters for per-
formance calculations. Therefore, only compounds with pre-
cise X-ray densities have been studied for their performan-
ces. The detonation and propulsion parameters of 2, 4–7, 9,
and 20 were calculated using the program EXPLO5 V5.05[39]
and are gathered in Table 3. The program is based on the
steady-state model of equilibrium detonation and uses the
Becker–Kistiakowsky–Wilson equation of state (BKW
E.O.S) for gaseous detonation products and Cowan–Fickett
E.O.S. for solid carbon.[40] The program is designed to
enable the calculation of detonation parameters at the
Chapman–Jouguet point. The calculations were performed
X
X
DfHꢂ
¼ HðMolecule, 298Þ
ꢀ
HꢂðAtoms, 298Þ þ
DfHꢂ
ðAtoms, 298Þ
ðg, M, 298Þ
ð1Þ
For calculation of the solid-state energy of formation
(Table 2) of 2, 4–7, 9, and 20, the lattice energy (UL) and lat-
tice enthalpy (DHL) were calculated from the corresponding
molecular volumes (obtained from X-ray elucidations) ac-
cording to the equations provided by Jenkins and Glasser.[38]
Table 2. Solid state energies of formation (DfU8).
b
[c]
[d]
DfH8 (g)[a]
[kJmolꢀ1
VM
nm3
/
UL
[kJmolꢀ1
DHL
[kJmolꢀ1
DfH8(s)[e]
[kJmolꢀ1
Dn[f]
DfU8(s)[g]
[kJmolꢀ1
Formula
M
A
DfU8(s)[h]
[kJkgꢀ1
G
]
E
]
G
]
E
]
G
]
[gmolꢀ1
]
N
]
2
4
5
6
7
9
20
876.1
902.5
911.9
1013.0
1114.6
1140.9
1411.5*
0.137
0.139
0.204
0.217
0.231
0.226
0.318
559.0
556.2
502.0
494.4
486.4
489.1
1437.4
563.9
561.2
507.0
499.3
491.4
494.0
1452.3
312.2
341.3
404.9
513.6
623.2
646.9
ꢀ40.8
5.5
5.5
8.5
9.5
10.5
10.5
16.5
325.9
354.9
426.0
537.2
649.2
672.9
0.1
C2H4N6O
C2H4N6O
C3H7N9O
C3H8N10O
C3H9N11O
C3H9N11O
C4H14N14O5
128.09
128.09
185.15
200.16
215.18
215.18
338.24
2543.3
2770.3
2300.3
2683.0
3016.5
3126.6
0.4
[a] Gas-phase enthalpies of formation (those of the ionic compounds are taken as the respective sums of the non-interacting component ions);* gas-
phase enthalpy of three water molecules were subtracted; [b] molecular volume of the molecular unit in the crystal structure; [c] lattice energy calculated
by the Glasser–Jenkins equation; [d] lattice enthalpy calculated by the Glasser–Jenkins equation; [e] solid-state molar heat of formation; [f] change of
moles of gaseous components; [g] molar energy of formation; [h] energy of formation (mass-dependent).
Chem. Asian J. 2013, 8, 148 – 159
153
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
Table 3. Energetic properties and detonation parameters of 2, 4–7, 9, and 20.
2
4
5
6
7
9
20
TNT
Formula
C2H4N6O
128.09
15
216
0.30
65.61
ꢀ62.45
184
1.554
325.9
2543.3
C2H4N6O
128.09
35
360
0.75
65.61
ꢀ62.45
172
1.526
354.9
2770.3
C3H7N9O
185.15
40
324
1.5
68.09
ꢀ73.54
228
1.504
426.0
2300.3
C3H8N10O
200.16
40
324
0.50
69.98
ꢀ71.93
152
1.534
537.2
2683.0
C3H9N11O
215.18
40
324
0.55
71.60
ꢀ70.63
160
1.550
649.2
3016.5
C3H9N11O
215.18
40
216
0.50
71.60
ꢀ70.63
150
1.583
672.9
3126.6
C4H14N14O5
338.24
40
240
0.50
57.97
ꢀ47.30
189
1.627
ꢀ40.8
0.4
C7H5N3O6
227.13
15[41]
353
3.5
18.50
ꢀ73.96
290
Molecular Mass [gmolꢀ1
IS [J][a]
]
FS [N][b]
ESD-test [J][c]
N [%][d]
W [%][e]
Tdec. [8C][f]
Density [gcmꢀ3
]
1.713
N
[g]
DfHm8 [kJmolꢀ1
]
ꢀ55.5
[h]
DfU8 [kJkgꢀ1
]
ꢀ168.0
[i]
EXPLO5.05:
[j]
ꢀDEU8 [kJkgꢀ1
]
4609
3288
222
7749
762
4831
3412
220
7730
762
3957
2842
196
7451
771
4277
2971
219
7790
788
4559
3060
237
8044
803
227
4666
3084
251
8214
803
229
3715
2746
227
7799
840
195
5258
3663
235
7459
569
TE [K][k]
pCJ [kbar][l]
[m]
D [msꢀ1
]
[n]
Gas vol. [Lkgꢀ1
]
IS [s][o]
222
228
207
218
205
[a] impact sensitivity (BAM drop hammer, 1 of 6); [b] friction sensitivity (BAM friction tester, 1 of 6); [c] electrostatic discharge device (OZM); [d] ni-
trogen content; [e] oxygen balance;[43] [f] decomposition temperature from DSC (b=58C); [g] estimated from X-ray diffraction; [h] calculated (CBS-4M)
heat of formation; [i] calculated energy of formation; [j] Energy of explosion; [k] explosion temperature; [l] detonation pressure; [m] detonation velocity;
[n] assuming only gaseous products; [o] specific impulse calculated at isobaric (60 bar) rocket conditions.
using the maximum densities according to the crystal struc-
tures at low temperatures and the calculated energies of for-
mation.
with the known cyanotetrazolate-1-oxide gave energetic
salts of both oxide-containing anions after metathesis reac-
tions. These nitrogen-rich salts show energetic performances
in the range of TNT; however, only salts 2 and 5 show ther-
mal stabilities above 1808C. NMR, IR, and Raman spectros-
copies proved useful for characterizing these materials. In
the presence of copper, the cyano group of both the 1- and
2-oxides hydrolyze to the corresponding carboxamide. The
protonated forms of both cyanotetrazolate-1- and 2-oxides
were able to form dihydrotetrazines upon reaction with hy-
drazine. In the case of the 2-oxide, the dihydrotetrazine can
be oxidized to the tetrazine, the ammonium salt of which
was fully characterized, illustrating the unique heterocyclic
system containing both tetrazole oxides and a 1,2,4,5-tetra-
zine ring. These compounds may provide base materials or
synthetic strategies to new energetic materials.
With respect to their detonation performance the best
values were obtained for triaminoguanidinium salts 7 and 9,
with 9 being slightly higher (8044 and 8214 msꢀ1, respective-
ly), thus indicating higher performance for the 1-oxides.
However, when ammonium salts 2 and 4 are compared,
there is no appreciable difference between the two (7749
and 7730 msꢀ1, respectively). All compounds prepared are
of comparable or higher performance than trinitrotoluene
(TNT), but lower than those of the commonly used military
explosives like hexogen (RDX) and octogen (HMX).
We also calculated the specific impulse IS (using the pure
compound at 60 bar isobaric rocket conditions), which can
be related to the potential use as propellant ingredient. The
highest IS was computed for compounds 4, 7, and 9 (228,
227, and 229 s, respectively).
The sensitivities of all compounds were determined by
standard methods (see the Experimental Section). The only
highly sensitive compound is compound 18, which when
completely dry can explode from only slight impacts. How-
ever, due to its high hygroscopicity, this compoundꢃs sensi-
tivity rapidly decreases upon standing at ambient conditions.
The remainder of compounds in this work are of much
lower sensitivity, generally being classified as “less sensitive”
to “sensitive” energetic materials according to the UN Rec-
ommendations on the Transport of Dangerous Goods.[44]
Experimental Section
General
All reagents and solvents were used as received (Sigma–Aldrich, Fluka,
and Acros Organics) unless stated otherwise. Sodium cyanotetrazolate-1-
oxide was prepared according to the literature procedure.[22] Melting and
decomposition points were measured with a Linseis PT10 differential
scanning calorimeter using heating rates of 58Cminꢀ1 1H, 13C and
.
15N NMR spectra were measured with a JEOL Eclipse 270 or 400 MHz
instrument. All chemical shifts are given in ppm relative to TMS (1H,
13C) or nitromethane (15N). Infrared spectra were measured with
a Perkin–Elmer FT-IR Spectrum BXII instrument equipped with a Smith
Dura SampIIR II ATR unit. Transmittance values are described as
strong (s), medium (m), and weak (w). Mass spectra were measured on
a JEOL MStation JMS 700 instrument. Raman spectra were measured
Conclusions
with
a Perkin–Elmer Spectrum 2000R NIR FT-Raman instrument
equipped with a Nd:YAG laser (1064 nm). The intensities are reported as
percentages of the most intensive peak and are given in parentheses. Ele-
mental analyses were performed with a Netsch STA 429 simultaneous
The direct oxidation of the cyanotetrazolate anion with
Oxone gave the cyanotetrazolate-2-oxide anion. This, along
Chem. Asian J. 2013, 8, 148 – 159
154
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
thermal analyzer. Sensitivity data were determined using a BAM drop
hammer and a BAM friction tester. The electrostatic sensitivity tests
were carried out using the electric spark tester ESD 2010 EN (OZM Re-
search) operating with the “Winspark 1.15” software package. XRD was
performed on an Oxford Xcalibur3 diffractometer with a Spellman gen-
erator (voltage 50 kV, current 40 mA) and a KappaCCD detector using
MoKa radiation (l=0.71073 ꢄ) at low temperature (173 K). The data col-
lection and reduction was carried out using the CrysAlisPro software.[45]
The structures were solved either with SHELXS-97[46] or SIR-92,[47] re-
fined with SHELXL-97[48], and finally checked using the PLATON[49]
software integrated in the WINGX[50] software suite. All hydrogen atoms
were found and freely refined. Friedel pairs of non-centrosymmetric
space groups have been merged using the MERG3 command. The ab-
sorptions were corrected with a Scale3 Abspack multi-scan method.[51]
CCDC 899950 (2), CCDC 899952 (4), CCDC 899957 (5), CCDC 899956
(6), CCDC 899951 (7), CCDC 899953 (9), CCDC 899955 (10),
CCDC 899954 (11), and CCDC 899949 (20) contain the supplementary
crystallographic data for this paper. These data can be obtained free of
charge from the Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
2544 (w), 2349 (w), 2259 (m), 2179 (w), 2136 (w), 1807 (w), 1708 (w),
1692 (m), 1591 (w), 1546 (w), 1472 (s), 1455 (w), 1438 (s), 1430 (s), 1401
(m), 1387 (m), 1370 (w), 1344 (s), 1226 (s), 1111 (w), 1073 (m), 1013 (m),
792 (m), 723 (m), 698 cmꢀ1 (w); Raman (1064 nm): n˜ =3047 (3), 2261
(100), 1700 (1), 1484 (1), 1442 (21), 1389 (8), 1356 (1), 1228 (3), 1109
(14), 1078 (1), 797 (4), 607 (1), 725 (3), 575 (3), 501 (5), 486 (1), 343 cmꢀ1
(1);1H NMR ([D6]DMSO): d=7.2 ppm (brs, 4H, NH4); 13C NMR
([D6]DMSO): d=132.6 (s, 1C, CN4O), 112.2 (s, 1C, CN); MS m/z:
(FABꢀ) 110.0 ppm (C2N5O); (FAB+) m/z: 18.1 (NH4); elemental analysis
calcd (%) for C2N6H4O (128.09): C 18.75, N 65.61, H 3.15; found: C
19.02, N 65.36, H 3.01; BAM impact: 15 J; BAM friction: 216 N; ESD:
300 mJ.
Silver cyanotetrazolate-1-oxide (3)
Sodium cyanotetrazolate-1-oxide (200 mg, 1.4 mmol) was dissolved in
10 mL of distilled water. Under constant stirring in the dark, a solution
of silver nitrate (238 mg, 1.4 mmol) in 10 mL water was added, and 3
started to precipitate immediately. The light yellow suspension was
stirred for 20 min, filtered under suction, and washed with distilled water.
After drying in the dark, 3 was obtained as a white solid (220 mg, 72%).
DSC (58Cminꢀ1): 201 (Tdec); IR: n˜ =3619 (w), 3448 (w), 2248 (w), 1572
(w), 1470 (s), 1444 (m), 1427 (m), 1413 (m), 1378 (w), 1330 (w), 1257 (s),
1241 (s), 1225 (w), 1208 (m), 1159 (w), 1096 (w), 1019 (w), 784 (s),
700 cmꢀ1 (w); 13C NMR ([D6]DMSO): d=123.8 (s); 110.7 ppm (s); MS
(FABꢀ) m/z: 110.0 (C2N5Oꢀ); elemental analysis calcd (%) for AgC2N5O
(217.92): C 11.02, H 0.00, N 32.14; found: C 11.23; H 0.00, N 31.52; BAM
impact: >4 J; BAM friction: 120 N; ESD: 80 mJ.
CAUTION! The described compounds are energetic materials with sensi-
tivity to various stimuli. While we encountered no issues in the handling of
these materials, proper protective measures (face shield, ear protection,
body armor, Kevlar gloves, and earthened equipment) should be used at
all times. Compound 18 is extremely sensitive when dry and should only
be handled in small quantities or wet.
Silver cyanotetrazolate-2-oxide (1)
Ammonium cyanotetrazolate-1-oxide (4)
Sodium cyanotetrazolate·1.5H2O (5 g, 34.7 mmol) was dissolved in 70 mL
of distilled water, and potassium acetate (29.8 g, 304 mmol) was added.
The solution was heated to 408C, and Oxone (66.8 g, 98 mmol) was
added slowly. After stirring of the suspension for 20 h at 408C, the solu-
tion was poured into 1.6 L of acetone and precipitated salts were filtered
off. After evaporation of the solvent under reduced pressure, the remain-
ing solid was dissolved in ethanol. The insoluble residues were filtered
off, and the filtrate was evaporated under vacuum. The colorless solid
was dissolved in 100 mL of distilled water, and a solution of silver nitrate
(5.9 g, 34.7 mmol) in 100 mL of distilled water was added in the dark
while stirring. Still in the dark, the colorless suspension was stirred for
15 min, filtered, and washed with 20 mL of distilled water. After drying
Sodium tributylammoniumsulfate (30 mL, 0.8m, 24 mmol) was added to
a
solution of sodium cyanotetrazolate-1-oxide (0.93 g, 6.6 mmol) in
20 mL of distilled water. After stirring for 30 min, the solution was ex-
tracted six times with 15 mL of ethyl acetate. The combined ethyl acetate
fractions were then evaporated under reduced pressure. The remaining
slightly yellow oil was dissolved in methanol and passed through
a column of Amberlyst 15 ion-exchange resin loaded with ammonium
cations at a slow rate (ca. 1.5 h). The yellow eluent was evaporated to
dryness and recrystallized from 1-propanol to yield 4 as a white solid
(0.205 g, 24%). DSC (58C min ꢀ1): 1608C (mp), 1728C (dec); IR: n˜ =
3171 (w), 2995 (w), 2829 (w), 2255 (w), 2159 (w), 1695 (w), 1534 (w),
1463 (m), 1429 (s), 1406 (vs), 1241 (s), 1219 (m), 1148 (w), 1080 (w), 1007
(w), 768 (m), 692 cmꢀ1 (w); Raman (1064 nm): n˜ =2257 (100), 1466 (50),
1415 (2), 1392 (2), 1246 (3), 1221 (20), 1147 (10), 1091 (6), 1010 (14), 771
(15), 638 (8); 547 (3), 495 (10), 413 (2), 1079 (1), 182 (21), 109 (11), 718
(2), 697 cmꢀ1 (1); 13C NMR ([D6]DMSO): d=123.9 (s, -CN4); 110.8 ppm
in the dark,
1 was obtained as a white solid (5.5 g, 73%). DSC
(58Cminꢀ1): 2248C (dec); IR: n˜ =3627 (w), 3464 (w), 2921 (m), 2242 (m),
1596 (w), 1441 (m), 1428 (m), 1403 (m), 1365 (s), 1340 (m), 1267 (w),
1225 (m), 1090 (w), 1013 (m), 812 (s), 710 cmꢀ1 (s); 13C NMR
([D6]DMSO): d=132.0 (s, 1C, CN4O), 112.3 ppm (s, 1C, CN); MS
(FABꢀ) m/z: 110.0 (C2N5O); (FAB+) m/z 107.0 (Ag); elemental analysis
calcd (%) for AgC2N5O (217.92): C 11.02, N 32.14, H 0.00; found: C
11.32, N 31.96; H 0.00. BAM impact: 8 J; BAM friction: 240 N; ESD:
50 mJ.
1
(s, -CN); H NMR ([D6]DMSO): d=7.14 ppm (s, 4H, NH4+); MS (FAB+
) m/z: 18.0 (NH4+); (FABꢀ) m/z: 110.0 (C2N5Oꢀ); elemental analysis
calcd (%) for NH4C2N5O (128.09): C 18.75, H 3.15, N 65.61; found: C
19.26, H 2.96, N 64.68; BAM impact: 35 J; BAM friction: 360 N; ESD:
0.75 J.
Ammonium cyanotetrazolate-2-oxide (2)
Aminoguanidinium cyanotetrazolate-2-oxide (5)
Sodium cyanotetrazolate·1.5H2O (10 g, 69.4 mmol) was dissolved in
240 mL of distilled water. Next, potassium acetate (59.6 g, 608 mmol) was
added and the solution heated to 408C. Subsequently, Oxone (120 g,
196 mmol) was added in small portions during the course of 1 h. The sus-
pension was stirred for 20 h at 408C, followed by the addition of suffi-
cient water to dissolve all solids. The solution was then allowed to slowly
cool down to room temperature, and an excess of sodium tributylammo-
nium sulfate (NaBu3NHSO4; 0.8m, 300 mL) was added. The solution was
extracted with ethylacetate (5ꢅ200 mL), and the combined organic phase
was combined and dried over anhydrous magnesium sulfate followed by
the evaporation of the solvent under vacuum to give a colorless oil. The
oil was mixed with 12 mL of methanol, and the solution was passed
through a column of Amberlyst 15 ion exchange resin loaded with am-
monium ions. The colorless eluent was evaporated to dryness and recrys-
tallized from acetonitrile to give ammonium 5-cyanotetrazolate-2-oxide
as colorless crystals (4.9 g, 55%) . DSC (58Cminꢀ1): 1768C (mp), 1848C
(dec); IR: n˜ =3697 (w), 3141 (m), 3020 (s), 2918 (w), 2890 (w), 2856 (w),
To a stirred solution of aminoguanidinium chloride (127 mg, 1.15 mmol)
in 20 mL of distilled water, finely powdered 1 (250 mg, 1.15 mmol) was
added. The suspension was stirred for 30 min and was filtered in the
dark. The filtrate was evaporated to dryness to give 5 as colorless crystals
(197 mg, 93%). DSC (58Cminꢀ1): 2288C (dec); IR: n˜ =3540 (w), 3321
(m), 3262 (m), 3158 (m), 2869 (w), 2774 (w), 2353 (w), 2256 (m), 2198
(w), 1998 (w), 1660 (s), 1613 (w), 1461 (w), 1434 (w), 1421 (w), 1393 (w),
1360 (m), 1326 (w), 1243 (m), 1213 (w), 1512 (w), 1106 (w), 1070 (w),
1049 (w), 1011 (w), 973(w), 953 (m), 824 (w), 798 (w), 771 (w), 741 (w),
718 (w), 672 cmꢀ1 (w); Raman (1064 nm): n˜ =3367 (1), 3334 (1), 3274 (4),
3232 (1), 2259 (100), 1683 (3), 1620 (2), 1569 (1), 1436 (30), 1399 (1),
1379 (1), 1238 (1), 1217 (2), 1095 (10), 1074 (4), 1019 (43), 959 (6), 802
(6), 719 (2), 614 (3), 571 (7), 518 (2), 502 (8), 484 (4), 337 cmꢀ1 (2);
1H NMR ([D6]DMSO): d=8.63 (s, 1H, C-NH-N), 7.37 (brs, 2H, C-NH2),
7.04 (brs, 2H, C-NH2), 4.77 ppm (s, 2H, N-NH2); 13C NMR
([D6]DMSO): d=159.4 (s, 1C, CACTHNUGTRENNUG(NH2)2ACHTUGNTRNE(NUGN NHNH2), 132.0 (s, 1C, CN4O),
Chem. Asian J. 2013, 8, 148 – 159
155
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
112.6 ppm (s, 1C, CN); MS (FABꢀ) m/z: 110.0 (C2N5O); (FAB+) m/z:
Triaminoguanindinium cyanotetrazolate-1-oxide (9)
75.1 (CN4H7); elemental analysis calcd (%) for CN4H7C2N5O (200.16): C
19.46, N 68.09, H 3.81; found: C 19.07, N 64.00, H 3.62. BAM impact:
40 J; BAM friction: 324 N; ESD: 1.5 J.
In the dark, 3 (250 mg, 1.15 mmol) was added to a solution of triamino-
guanidinium chloride (160 mg, 1.15 mmol) in 20 mL of distilled water.
The solution was shaken for about 10 min and filtered. The yellow filtrate
was evaporated by blowing a N2 flow on the liquid surface to afford 9 as
colorless crystals (0.19 g, 77%). DSC (58Cminꢀ1): 1348C (m.p.), 1508C
(dec); IR: n˜ =3343 (m), 3230 (m), 3095 (w), 3008 (w), 2782 (w), 2659 (w),
2248 (w), 1841 (w), 1674 (vs), 1611 (w), 1590 (w), 1536 (m), 1458 (w),
1418 (m), 1387 (w), 1345 (m), 1246 (s), 1210 (w), 1190 (m), 1131 (s), 1073
(w), 1014 (w), 995 (m), 942 (s), 928 (s), 793 (w), 770 (w), 684 cmꢀ1 (w);
Raman (1064 nm): n˜ =3345 (4), 3239 (8), 2249 (98), 2194 (2), 1678 (4),
1646 (1), 1459 (47), 1391 (2), 1350 (3), 1248 (2), 1211 (16), 1202 (3); 1138
(9), 1074 (18), 1011 (10), 880 (10), 771 (15), 696 (1), 647 (10), 548 (4), 494
(12), 429 (6), 313 (1), 257 cmꢀ1 (4); 13C NMR ([D6]DMSO): d=159.6 (s,
TAG +); 123.9 (s, CN4); 110.8 ppm (s, CN); 1H NMR ([D6]DMSO): d=
8.58 (s, 3H, NH-NH2); 4.48 ppm (s, 6H, NH-NH2); MS (FAB+) m/z:
105.1 (CN6H9+); (FABꢀ) m/z: 110.0 (C2N5Oꢀ); elemental analysis calcd
(%) for CN6H9C2N5O (215.18): C 16.75, H 4.22, N 71.60; found: C 16.87,
H 4.12, N 70.13; BAM impact: 40 J; BAM friction: 216 N; ESD: 0.5 J.
Diaminoguanidinium cyanotetrazolate-2-oxide (6)
Finely powdered 1 (250 mg, 1.15 mmol) was added to a solution of diami-
noguanidinium iodide (249 mg, 1.15 mmol) in 20 mL of distilled water.
The suspension was slowly shaken by hand for 15 min and filtered in the
dark. The filtrate was evaporated to dryness to yield 6 as colorless crys-
tals (193.6 mg, 84%). DSC (58Cminꢀ1): 1358C (mp), 1528C (dec); IR:
n˜ =3310 (w), 3234 (s), 3174 (s), 3000 (w), 2889 (w), 2251 (m), 1986 (w),
1913 8w), 1736 (w), 1668 (s), 1649 (w), 1596 (w), 1461 (w), 1436 (m),
1421 (w), 1394 (m), 1358 (s), 1272 (w), 1232 (m), 1215 (w), 1177 (m),
1120 (w), 1066 (w), 968 (s), 930 (w), 800 (m), 767 (m), 713 cmꢀ1 (w);
Raman (1064 nm): n˜ =3791 (2), 3341 (1), 3240 (7), 2256 (100), 1689 (2),
1637 (3), 1437 (24), 1409 (3), 1367 (1), 1322 (1), 1234 (2), 1184 (4), 1090
(12), 1069 (2), 1010 (38), 931 (9), 802 (6), 719 (2), 572 (7), 549 (3), 499
(11), 479 (4), 396 (1), 366 (2), 265 cmꢀ1 (4); 1H NMR ([D6]DMSO): d=
8.54 (brs, 2H, C-NH-NH2), 7.13 (s, 2H, C-NH2), 4.58 ppm (s, 4H, N-
NH2); 13C NMR ([D6]DMSO): d=160.3 (s, 1C, C
ACHTUNGRTENN(UG NH2)AHCUTNGTREN(NUNG NHNH2)2), 131.6
Copper(II) bis(carboxamide-tetrazolate-2-oxide) dihydrate (10)
(s, 1C, CN4O), 112.8 ppm (s, 1C, CN); MS (FABꢀ) m/z: 110.0 (C2N5O);
(FAB+) m/z: 90.0 (CN5H8); elemental analysis calcd (%) for
CN5H8C2N5O (200.16): C 18.00, N 69.98, H 4.03; found: C 18.55, N 67.93,
H 4.01. BAM impact: 40 J; BAM friction: 324 N; ESD: 500 mJ.
To a solution of copper (II) chloride dihydrate (78 mg, 0.46 mmol) in
15 mL of distilled water, finely powdered 1 (200 mg, 0.92 mmol) was
added in the dark. The suspension was carefully shaken by hand for
15 min in the dark followed by filtration. The filtrate was evaporated
under heating (408C) to give 10 as green single crystals (89.3 mg, 55%).
IR: n˜ =3854 (w), 3752 (w), 3377 (w), 3341 (w), 3270 (w), 3068 (m), 2782
(w), 2362 (w), 2333 (w), 2206 (w), 1734 (w), 1670 (s), 1590 (m), 1522 (m),
1444 (m), 1406 (w), 1387 (m), 1333 (s), 1246 (m), 1150 (w), 1119 (w),
1069 (w), 999 (w), 981 (w), 894 (w), 872 (w), 822 (m), 784 (w), 703 (m),
Triaminoguanidinium cyanotetrazolate-2-oxide (7)
Finely powdered 1 (250 mg, 1.15 mmol) was added to a solution of tria-
minoguanidinium chloride (161.2 mg, 1.15 mmol) in 20 mL of distilled
water in the dark. The suspension was carefully shaken for 15 min, fil-
tered, and rinsed with 10 mL of distilled water in the dark. The filtrate
was evaporated to yield 7 as colorless crystals (214.2 mg, 87%). DSC
(58C min ꢀ1): 1498C (m.p.), 1668C (dec); IR: n˜ =33614 (w), 3325 (w),
3208 (m), 3119 (w), 2354 (w), 2327 (w), 2256 (m), 1723 (w), 1674 (s),
1587 (w), 1554 (w), 1437 (m), 1400 (m), 1372 (w), 1332 (m), 1246 (w),
1224 (w), 1207 (w), 1133 (s), 1068 (w), 979 (s), 799 (m), 734 (w), 718 cmꢀ1
(w); Raman (1064 nm): n˜ =3234 (10), 2258 (97), 1680 (4), 1644 (2), 1439
(15), 1410 (4), 1384 (3), 1322 (2), 1208 (3), 1140 (6), 1075 814), 1001 (36),
886 (9), 801 (8), 734 (1), 719 (3), 680 (4), 639 (3), 600 (2), 571 (8), 503
(8), 477 (7), 410 (4), 354 cmꢀ1 (3); 1H NMR ([D6]DMSO): d=8.58 (brs,
3H, C-NH-NH2), 4.48 ppm (brs, 6H, N-NH2); 13C NMR ([D6]DMSO):
687 cmꢀ1 (m); elemental analysis calcd (%) for Cu
ACHTUNGTRNE(UNG C2N5H4O3)2 (355.65):
C 13.51, N 39.38, H, 2.27; found: C 14.08, N 41.28, H 2.2.
Copper(II) bis(carboxamide-tetrazolate-1-oxide) dihydrate (11)
3 (200 mg, 0.92 mmol) was added to a solution of copper(II) chloride di-
hydrate (78 mg, 0.46 mmol) in 20 mL of distilled water. The solution was
shaken for 10 min and filtered in the dark. The light blue filtrate was
evaporated under heating (408C) to yield 11 as green crystals (124 mg,
0.35 mmol). IR: n˜ =3854 (w), 3746 (w), 3651 (w), 3447 (w), 3377 (w),
3298 (w), 3220 (w), 3170 (w), 2361 (m), 2338 (m), 2111 (w), 1734 (w),
1674 (vs), 1653 (s), 1610 (s), 1560 (w), 1530 (m), 1473 (w), 1457 (w), 1435
(w), 1419 (w), 1378 (m), 1338 (w), 1251 (m), 1208 (m), 1118 (w), 1092
(w), 1016 (w), 820 (w), 784 (m), 732 (w), 706 (m), 684 (w), 668 cmꢀ1 (w);
elemental analysis calcd (%) for CuC4N10O6H8 (355.72): C 13.51, H 2.27,
N 39.38; found: C 13.78, H 2.23, N 40.63.
d=159.6 (s, 1C, C
ACHTUNGTRENNUNG
CN); MS (FABꢀ) m/z: 109.9 (C2N5O); (FAB+) m/z:105.1 (C
AHCTUNGTRENNUNG
elemental analysis calcd (%) for CN6H9C2N5O (215.18): C 16.74, N 71.6,
H 4.21; found: C 16.72, N 70.77, H 4.19. BAM impact: 40 J; BAM fric-
tion: 324 N; ESD: 550 mJ.
Hydrazinium 1,4-bis(2-N-oxidotetrazolate)-dihydro-1,2,4,5-tetrazine (12)
Aminoguanidinium cyanotetrazolate-1-oxide (8)
Sodium-5-cyano-tetrazolate·1.5H2O (5.00 g, 34.7 mmol, 1.0 equiv) was
dissolved in 25 mL water. The solution was cooled to 08C and nitric acid
(18.5 mL, 2m, 37.0 mmol, 1.1 equiv) was added. The mixture was stirred
for 30 min before it was allowed to warm up to room temperature. The
solvent was then removed under reduced pressure at room temperature
and the residue was dissolved in ethanol. Remaining solids were filtered
off, and the ethanol was evaporated at room temperature under reduced
pressure to yield crude 5-cyanotetrazole. The crude product was dissolved
in 66 mL water. Subsequently, 2m potassium hydroxide (17.5 mL,
35.0 mmol, 1.0 equiv), potassium acetate (29.80 g, 303.6 mmol, 8.7 equiv),
and Oxone (66.03 g, 107.4 mmol, 3.1 equiv) were added. The solution was
stirred at 408C overnight. The solution was then poured into acetone
(1.60 L) and stirred, followed by filtration of precipitated salts. After
evaporation of the acetone under reduced pressure, the remaining solids
were dissolved in hot ethanol. The insoluble remains were filtered off,
and the ethanol was removed under reduced pressure. The residue was
then dissolved in 15 mL water. The solution was cooled to 08C before 2m
nitric acid (17.4 mL, 34.7 mmol, 1.0 equiv) was added. After stirring the
mixture for 30 min, the solvent was evaporated under high vacuum at
room temperature. The solid residue was dissolved in dry ethanol, and in-
soluble remains were filtered off. Next, hydrazine hydrate (2.96 mL,
To a solution of aminoguanidinium chloride (102 mg, 0.92 mmol) in
20 mL of distilled water, 3 (200 mg, 0.92 mmol) was added in the dark,
and the mixture was shaken for 10 min. After filtration, the filtrate was
evaporated to dryness to yield 8 as a white solid (0.16 g, 94%). DSC
(58Cminꢀ1): 668C (m.p.), 1648C (dec); IR: n˜ =3467 (w), 3361 (m), 3143
(w), 3060 (w), 2972 (w), 2853 (w), 2643 (w), 2251 (w), 2171 (w), 1655
(vs), 1625 (m), 1463 (m), 1413 (m), 1245 (s), 1221 (m), 1144 (w), 1093
(w), 1007 (w), 973 (w), 889 (w), 772 (m), 682 cmꢀ1 (w); Raman
(1064 nm): n˜ =3282 (5), 3229 (1), 3197 (1), 3336 (1), 3355 (1), 2490 (1),
2432 (2), 2253 (98), 2198 (2), 1682 (2), 1631 (5), 1564 (2), 1466 (82), 1417
(3), 1387 (2), 1252 (2), 1223 (35), 1145 (18), 1091 (14), 1009 (18), 973
(21), 776 (25), 717 (2), 694 (1), 639 (12), 550 (4), 492 (15), 416 (3), 360
(2), 246 cmꢀ1 (1); 13C NMR ([D6]DMSO): d=159.4 (s, AG+); 123.9 (s,
CN4); 110.9 ppm (s, CN); 1H NMR ([D6]DMSO): d=8.58 (s, 1H, NH-
NH2); 7.01 (brs, 2H, NH2); 6.99 (brs, 2H, NH2); 4.51 ppm (brs, 2H, NH-
NH2); m/z (FAB+): 75.1 (CN4H7+); m/z (FABꢀ): 110.0 (C2N5Oꢀ); ele-
mental analysis calcd (%) for CN4H7C2N5O (185.15): C 19.46, H 3.81, N
68.09; found: C 19.14, H 3.72, N 64.67; BAM impact: 40 J; BAM friction:
216 N; ESD: 0.5 J.
Chem. Asian J. 2013, 8, 148 – 159
156
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
3.06 g, 60.9 mmol, 1.8 equiv) was added and the mixture was refluxed at
about 858C for 2 h before additional hydrazine hydrate (2.96 mL, 3.06 g,
60.9 mmol, 1.8 equiv) was added. Subsequently, the mixture was refluxed
for another 22 h. The precipitate was filtered off and rinsed with dry eth-
anol to yield 12 as a white solid (4.38 g, 13.9 mmol, 79.8% relative to the
amount of sodium 5-cyanotetrazolate sesquihydrate). DSC: 1768C (dec.);
IR: n˜ =3306 (w), 3272 (w), 3187 (w), 3148 (w), 3079 (w), 2945 (w), 2877
(w), 2649 (w), 2520 (w), 2151 (w), 2119 (w), 1637 (w), 1613 (w), 1545 (w),
1512 (w), 1461 (w), 1448 (w), 1406 (m), 1396 (m), 1372 (s), 1302 (w),
1246 (m), 1193 (w), 1100 (m), 1038 (w), 1014 (w), 993 (w), 972 (m), 864
(w), 783 (m), 749 (w), 724 (w), 701 (w), 650 cmꢀ1 (m); Raman (1064 nm):
n˜ =1662 (95), 1625 (8), 1589 (34), 1544 (46), 1515 (2), 1455 (31), 1414 (2),
1399 (6), 1374 (3), 1301 (2), 1237 (9), 1194 (2), 1119 (26), 1051 (5), 1030
(66), 975 (14), 843 (2), 763 (2), 787 (1), 749 (10), 702 (1), 646 (4), 597 (2),
541 (3), 456 (3), 333 cmꢀ1 (3); 13C NMR ([D6]DMSO,): d=148.10 (s)
140.54 ppm (s); MS (FAB+): m/z=33.1 (N2H5+), MS (FABꢀ, glycerine):
m/z=251.1 (C4H3N12O2ꢀ); elemental analysis calcd (%) for
(N2H5)2C4N12O2H2 (316.24): N 70.87, C 15.19, H 3.82; found: N 64.81, C
15.49, H 3.62; BAM impact: 35 J; BAM friction: 360 N; ESD 250 mJ.
(288.18): N 58.32, C 16.67, H 2.80; found: N 63.54, C 16.46, H 3.31; BAM
impact: 40 J; BAM friction: 360 N; ESD: 250 mJ.
1,4-Bis(1-hydroxytetrazole)-dihydro-1,2,4,5-tetrazine hydrate (15·H2O)
13 (1.84 g, 5.5 mmol, 1.0 equiv) was dissolved in as little hot water as pos-
sible, and insoluble material was filtered off. Subsequently, concentrated
hydrochloric acid (37 wt.%, 4 mL, 4.76 g, 48.3 mmol, 8.8 equiv) was
added and the solution was cooled to 68C. The precipitating product was
isolated by suction filtration and rinsed with cold water to yield 15·H2O
as a white solid (0.91 g, 61.1%). DSC: 1448C (dec.); IR: n˜ =3556 (w),
3329 (m), 3317 (m), 3234 (m), 3190 (m), 3048 (m), 2952 (w), 2933 (w),
2746 (w), 2651 (w), 2623 (w), 2365 (w), 2337 (w), 2198 (w), 2083 (w),
2048 (w), 1831 (w), 1695 (m), 1641 (m), 1594 (m), 1530 (m), 1469 (w),
1433 (s), 1320 (w), 1308 (w), 1265 (w), 1247 (w), 1230 (w), 1191 (w), 1148
(m), 1138 (m), 1114 (w), 1096 (m), 1062 (w), 1037 (m), 1003 (w), 975 (w),
962 (m), 922 (m), 857 (m), 786 (s), 757 (m), 735 (s), 717 (m), 694 (m),
686 cmꢀ1 (m); Raman (1064 nm): n˜ =3243 (4), 1671 (71), 1646 (15), 1567
(95), 1542 (4), 1464 (9), 1411 (1), 1392 (1), 1286 (4), 1244 (17), 1178 (2),
1138 (8), 1090 (15), 1024 (5), 1005 (1), 973 (1), 863 (8), 790 (3), 727 (12),
693 (12), 640 (4), 536 (3), 384 (3), 319 (3), 234 cmꢀ1 (2); 1H NMR
([D6]DMSO): d=9.78 (brs, N-H), 4.10 ppm (brs, O-H and H2O);
13C NMR ([D6]DMSO,): d=138.70 (s), 136.43 ppm (s); MS (DEI+): m/
z=252.3 (M+); elemental analysis calcd (%) for C4N12O2H4·H2O
(270.17): N 62.21, C 17.78, H 2.24; found: N 59.22, C 17.19, H 2.88; BAM
impact: 17 J; BAM friction: 192 N; ESD: 700 mJ.
Hydrazinium 1,4-bis(1-N-oxidotetrazolate)-dihydro-1,2,4,5-tetrazine (13)
Sodium cyanotetrazolate-1-oxide (2.00 g, 14.1 mmol, 1.0 equiv) was dis-
solved in 12 mL of water. The solution was then cooled to 08C before 2m
nitric acid (7.04 mL, 14.1 mmol, 1.0 equiv) was added. After stirring the
mixture for 30 min, the solvent was evaporated under reduced pressure
at room temperature. The solid residue was dissolved in dry ethanol, and
insoluble remains were filtered off. Subsequently, hydrazine hydrate
(1.20 mL, 1.24 g, 24.7 mmol, 1.8 equiv) was added and the mixture was
refluxed at 858C for 2 h before another portion of hydrazine hydrate
(1.20 mL, 1.24 g, 24.7 mmol, 1.8 equiv) was added. The mixture was re-
fluxed for another 22 h. The precipitate was filtered off and rinsed with
dry ethanol to yield 13 as a white solid (1.84 g, 82.5%). DSC: 1348C
(m.p.), 1808C (dec.); IR: n˜ =3589 (w), 3260 (s), 3183 (m), 3111 (m), 2968
(m), 2909 (m), 2726 (w), 2635 (w), 2298 (w), 2202 (w), 2056 (w), 1988
(w), 1954 (w), 1903 (w), 1653 (m), 1615 (m), 1538 (w), 1514 (s), 1457 (s),
1445 (s), 1411 (m), 1346 (w), 1318 (m), 1243 (s), 1167 (m), 1150 (w), 1103
(s), 1082 (s), 1005 (m), 988 (s), 951 (m), 853 (s), 782 (m), 737 (m), 725
(s), 698 (m), 654 cmꢀ1 (w); Raman (1064 nm): n˜ =3256 (13), 3220 (3),
3002 (3), 2929 (5), 1950 (4), 1907 (3), 1855 (3), 1806 (3), 1770 (3), 1732
(2), 1655 (94), 1594 (43), 1547 (48), 1518 (3), 1473 (28), 1437 (2), 1400
(4), 1354 (4), 1317 (2), 1299 (8), 1277 (2), 1243 (35), 1159 (16), 1143 (2);
1098 (28), 1044 (3), 1014 (16), 989 (2), 974 (4), 845 (16), 760 (6), 736 (11),
698 (5), 634 (7), 599 (3), 542 (4), 432 (7), 408 (2), 377 (3), 331 (3),
281 cmꢀ1 (3); 1H NMR ([D6]DMSO): d=10.04 (s, N-H), 7.07 ppm (s,
N2H5+); 13C NMR ([D6]DMSO,): d=140.44 (s), 134.26 ppm (s); MS
(FABꢀ, glycerin): m/z=251.1 (C4H3N12O2ꢀ); elemental analysis calcd (%)
for (N2H5)2C4N12O2H2 (316.24): N 70.87, C 15.19, H 3.82; found: N 65.55,
Ammonium 1,4-bis(2-N-oxidotetrazolate)-dihydro-1,2,4,5-tetrazine (16)
14·2H2O (200 mg, 0.79 mmol) was dissolved in 50 mL of distilled water,
and then 2m ammonia (0.8 mL, 1.59 mmol) was added. Subsequently,the
solvent was removed under reduced pressure to yield 16 as a solid
(185.5 mg, 82%). IR: n˜ =3262 (m), 3170 (m), 3026 (m), 2853 (m), 2119
(w), 1681 (w), 1604 (w), 1534 (w), 1512 (w), 1430 (m), 1403 (s), 1368 (s),
1274 (w), 1236 (m), 1200 (m), 1154 (w), 1124 (w), 1107 (w), 1048 (w),
1009 (m), 994 (m), 973 (w), 866 (w), 789 (m), 734 (m), 694 cmꢀ1 (w);
Raman (1064 nm): n˜ =3264 (3), 3085 (5), 1660 (98), 1536 (64), 1463 (26),
1410 (4), 1395 (1), 1235 (7), 1174 (5), 1122 (37), 1067 (2), 1022 (85), 994
(5), 971 (7), 821 (1), 858 (1), 790 (1), 767 (3), 751 (11), 695 (1), 645 (5),
601 (3), 548 (3), 452 (6), 327 cmꢀ1 (4); 1H NMR ([D6]DMSO): d=8.3 (s,
2H, C2N4H2), 7.3 ppm (s, 4H, NH4);13C NMR ([D6]DMSO): d=148.6 (s,
2C, -CN4O), 141.1 ppm (s, 2C, -C2N4-); m/z: (FABꢀ) 251 (C4H2N12O2); m/
z: (FAB+) 18.1 (NH4); elemental analysis calcd (%) for
(NH4)2C4N12O2H2 (286.22): C 16.77, N 68.51, H 3.52; found: C 16.37, N
66.96, H 3.73; BAM impact: 30 J; BAM friction: 360 N; ESD: 500 mJ.
Ammonium 1,4-bis(1-N-oxidotetrazolate)-dihydro-1,2,4,5-tetrazine
monohydrate (17·H2O)
To a solution of 15·H2O (0.20 g, 0.79 mmol) in about 4 mL distilled water
2m ammonia (0.83 mL, 1.66 mmol) was added. After that, the mixture
was stirred for 0.5 h and the solvent was evaporated under nitrogen flow
to afford 17·H2O as a white solid (0.22 g, 97%). IR: n˜ =3314 (w), 3268
(m), 3176 (w), 3040 (w), 2897 (w), 2855 (w), 2734 (w), 2633 (w), 1635
(w), 1549 (w), 1510 (m), 1433 (vs), 1415 (s), 1310 (w), 1282 (m), 1231
(m), 1165 (w), 1133 (w), 1093 (m), 1067 (w), 999 (w), 980 (w), 970 (m),
850 (w), 774 (w), 745 (w), 735 (w), 700 cmꢀ1 (w); Raman (1064 nm): n˜ =
3274 (2), 3176 (7), 2131 (2), 1653 (98), 1605 (11), 1536 (49), 1467 (21),
1398 (2), 1357 (1), 1289 (10), 1233 (40), 1148 (12), 1089 (17), 1007 (11),
968 (4), 844 (9), 756 (4), 739 (9), 699 (3), 653 (3), 639 (1), 533 (4), 414
(4), 381 (2), 323 (2), 273 cmꢀ1 (1); 13C NMR ([D6]DMSO): d=134.8 (s,
C
15.15,
H 3.75; BAM impact: 40 J; BAM friction:>360 N; ESD:
250 mJ.
1,4-Bis(2-hydroxytetrazole)-dihydro-1,2,4,5-tetrazine dihydrate (14·2H2O)
12 (950 mg, 3.0 mmol, 1.0 equiv) was dissolved in as little hot water as
possible, and insoluble remains were filtered off. Subsequently, concen-
trated hydrochloric acid (37 wt.%, 1.9 mL, 2.26 g, 22.9 mmol, 7.6 equiv)
was added and the solution was cooled to 68C. The precipitating product
was isolated by suction filtration and rinsed with cold water to yield
14·2H2O as a white solid (315 mg, 36.3%). DSC: 1168C (-H2O), 1628C
(dec.); IR: n˜ =3528 (w), 3421 (w), 3273 (m), 3191 (m), 3107 (w), 2975
(m), 2889 (m), 2525 (m), 2365 (m), 2119 (w), 1984 (w), 1972 (w), 1956
(w), 1629 (w), 1564 (m), 1547 (63), 1539 (m), 1512 (m), 1453 (w), 1446
(w), 1385 (s), 1366 (s), 1239 (s), 1197 (m), 1152 (m), 1129 (m), 1103 (m),
1041 (m), 1015 (m), 993 (s), 856 (m), 771 (s), 694 cmꢀ1 (s); Raman
(1064 nm): n˜ =3285 (3), 1665 (98), 1547 (63), 1456 (41), 1385 (3), 1242
(9), 1137 (13), 1038 (49), 974 (7), 842 (4), 767 (1), 750 (9), 633 (4), 599
(1), 543 (3), 463 (1), 416 (1), 331 cmꢀ1 (1); 1H NMR ([D6]DMSO): d=
8.86 (brs, -NH), 4.40 ppm (brs, -OH and hydration water); 13C NMR
([D6]DMSO,): d=150.39 (s), 139.71 ppm (s); MS (FABꢀ): m/z=251
(C4H3N12O2ꢀ); elemental analysis calcd (%) for C4N12O2H4·2H2O
1
2C, -C2N4-); 140.9 ppm (s, 2C, -CN4); H NMR ([D6]DMSO): d=10.11 (s,
4H, NH4+); 7.11 ppm (brs, 2H, -NH-); m/z (FAB+, NBA): 18.0 (NH4+);
m/z (FABꢀ, NBA): 251.0 (C4H3N12O2ꢀ); elemental analysis calcd (%) for
(NH4)2C4N12O2H2·H2O (304.23): C 15.78, H 3.98, N 64.46; found: C
15.80, H 3.96, N 64.54; BAM impact: 40 J; BAM friction: 240 N; ESD:
1.5 J.
1,4-Bis(2-hydroxytetrazole)-1,2,4,5-tetrazine (18)
To a suspension of 14·2H2O (100 mg, 0.35 mmol, 1.0 equiv) in 100 mL
acetonitrile, a solution of nitrogen dioxide in acetonitrile was added
Chem. Asian J. 2013, 8, 148 – 159
157
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
dropwise until the suspension became red and no more of the solid dis-
solved. The remaining solid was filtered off, and the solution was slowly
evaporated under a stream of nitrogen at room temperature. The solid
was then dried under high vacuum at 408C. WARNING: VERY EX-
PLOSIVE WHEN DRY! 13C NMR ([D6]DMSO,): d=158.4 (s),
154.9 ppm (s); MS (FABꢀ): m/z=249.2 (C4N12O2Hꢀ).
[7] W. McLellan, W. R. Hartley, M. Brower, Health advisory for hexahy-
dro-1,3,5-trinitro-1,3,5-triazinane. Technical Report PB90–273533;
Office of Drinking Water, U. S. Environmental Protection Agency,
Washington DC, 1988.
[8] N. Sikder, A. K. Sikder, N. R. Bulakh, B. R. Gandhe, J. Hazard.
Mater. 2004, 113, 35–43.
[9] P. E. Eaton, M. X. Zhang, R. Gilardi, N. Gelber, S. Iyer, R. Surape-
neni, Propellants Explos. Pyrotech. 2002, 27, 1–6.
[10] P. Carlqvist, H. ꢆstmark, T. Brinck, J. Phys. Chem. A 2004, 108,
7463–7467.
Ammonium 1,4,-bis(2-N-oxidotetrazolate)-1,2,4,5-tetrazine monohydrate
(20·H2O)
To a suspension of 14·2H2O (100 mg, 0.35 mmol, 1.0 equiv) in 100 mL
acetonitrile, a solution of nitrogen dioxide in acetonitrile was added
dropwise until the suspension became red and no more of the solid dis-
solved. The remaining solid was filtered off, and the solution was slowly
evaporated under a stream of nitrogen at room temperature. The ob-
tained product was dissolved in water, and then 2m ammonia (0.37 mL,
0.74 mmol) was added. Afterwards, the solution was evaporated under
a stream of nitrogen to yield 20·H2O (70 mg, 0.23 mmol) as a red solid
after drying under high vacuum. DSC: 958C (-H2O), 1898C (dec.); IR:
n˜ =3401 (w), 3165 (m), 3010 (m), 2821 (m), 2361 (w), 2258 (w), 2135 (w),
1831 (w), 1675 (w), 1604 (w), 1570 (w), 1534 (m), 1406 (s), 1354 (s), 1313
(s), 1273 (m), 1263 (m), 1248 (s), 1209 (m), 1098 (w), 1068 (m), 1044 (w),
1011 (m), 992 (m), 921 (w), 825 (w), 787 (m), 781 (m), 742 (w), 703 (w),
676 cmꢀ1 (w); Raman (1064 nm): n˜ =1997 (1), 1864 (2), 1628 (1), 1516
(100), 1495 (2), 1425 (7), 1391 (3), 1232 (1), 1152 (2), 1100 (29), 1088 (4),
1036 (3), 1002 (17), 988 (5), 820 (4), 764 (1), 601 (1), 465 cmꢀ1 (2);
1H NMR ([D6]DMSO): d=7.29 (brs, NH4+), 3.4 ppm (brs, H2O);
13C NMR ([D6]DMSO): d=158.15 (s), 150.92 ppm (s); MS (FABꢀ): m/
[11] Y.-C. Li, C. Qi, S. H. Li, H. J. Zhang, C.-H. Sun, Y.-Z. Yu, S.-P.
Pang, J. Am. Chem. Soc. 2010, 132, 12172–12173.
[12] T. M. Klapçtke, D. G. Piercey, Inorg. Chem. 2011, 50, 2732–2734.
[13] M. N. Glukhovtsev, B. Y. Simkin, V. I. Minkin, Zh. Org. Khim. 1988,
24, 2486–2488.
[14] S. Inagaki, N. Goto, J. Am. Chem. Soc. 1987, 109, 3234–3240.
[15] M. Noyman, S. Zilberg, Y. Haas, J. Phys. Chem. A 2009, 113, 7376–
7382.
[16] M. S. Molchanova, T. S. Pivina, E. A. Arnautova, N. S. Zefirov, J.
Mol. Struct. (Theochem.) 1999, 465, 11–24.
[17] M. Gçbel, K. Karaghiosoff, T. M. Klapçtke, D. G. Piercey, J. Stier-
storfer, J. Am. Chem. Soc. 2010, 132, 17216–17226.
[18] T. M. Klapçtke, D. G. Piercey, J. Stierstorfer, Chem. Eur. J. 2011, 17,
13068–13077.
[19] T. M. Klapçtke, D. G. Piercey, J. Stierstorfer, M. Weyrauther, Pro-
pellants Explos. Pyrotech. 2012, DOI: 10.1002/prep201100151.
[20] D. Fischer, N. Fischer, T. M. Klapçtke, D. G. Piercey, J. Stierstorfer,
J. Mater. Chem. 2012, DOI: 10:1039/c2m33646d.
[21] A. N. Binnikov, A. S. Kulikov, N. N. Makhov, I. V. Orchinnikov, T. S.
Pivina, 30th International Annual Conference of ICT, Karlsruhe,
Germany, June 29–July 2, 1999, p. 58.
z=249.1
(C4N12O2Hꢀ);
elemental
analysis
calcd
(%)
for
(NH4)2C4N12O2·H2O (302.22): N 64.89, C 15.89, H 3.34; found: N 59.69, C
16.03, H 3.45; BAM impact: 40 J; BAM friction: 240 N; ESD: 500 mJ;
[22] A. M. Churakov, S. L. Ioffe, V. S. Kuz’min, Yu. A. Strelenko, Yu. T.
Struchkov, V. A. Tartakovskii, Khim. Geterotsikl. Soedin. 1988, 12,
1666–1669.
[23] C. M. Sabatꢇ, E. Jeanneu, H. Delalu, Dalton Trans. 2012, 41, 3817–
3825.
Acknowledgements
Financial support of this work by the Ludwig-Maximilian University of
Munich (LMU), the U.S. Army Research Laboratory (ARL), the Arma-
ment Research, Development and Engineering Center (ARDEC), the
Strategic Environmental Research and Development Program (SERDP),
and the Office of Naval Research (ONR Global, title: “Synthesis and
[24] J. Sauer, G. R. Pabst, U. Holland, H.-S. Kim, S. Loebbecke, Eur. J.
Org. Chem. 2001, 697–706.
[25] Gaussian 09, Revision A.1, 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. Nakatsuji, M. Caricato, X.
Li, H. P. Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L. Son-
nenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa,
M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven,
J. A. Montgomery, 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, ꢆ.
Farkas, J. B. Foresman, J. V. Ortiz, J. Cioslowski, and D. J. Fox,
Gaussian, Inc., Wallingford CT, 2009.
Characterization of New High Energy Dense Oxidizers (HEDO)
-
NICOP Effort ”) under contract nos. W911NF-09-2-0018 (ARL),
W911NF-09-1-0120 (ARDEC), W011NF-09-1-0056 (ARDEC), and 10
WPSEED01-002/WP-1765 (SERDP) is gratefully acknowledged. The au-
thors acknowledge collaborations with Dr. Mila Krupka (OZM Research,
Czech Republic) in the development of new testing and evaluation meth-
´
ods for energetic materials and with Dr. Muhamed Suceska (Brodarski
Institute, Croatia) in the development of new computational codes to
predict the detonation and propulsion parameters of novel explosives.
We are indebted to and thank Drs. Betsy M. Rice and Brad Forch (ARL,
Aberdeen, Proving Ground, MD) and Mr. Gary Chen (ARDEC, Picatin-
ny Arsenal, NJ) for many helpful and inspired discussions and support of
our work. The authors want to thank S. Huber for measuring the sensitiv-
ities.
[26] A. D. Becke, J. Chem. Phys. 1993, 98, 5648–5652.
[27] C. Lee, W. Yang, R. G. Parr, Phys. Rev. B 1988, 37, 785–789.
[28] D. E. Woon, T. H. Dunning, Jr., R. J. Harrison, J. Chem. Phys. 1993,
98, 1358–1371.
[29] R. A. Kendall, T. H. Dunning, Jr., R. J. Harrison, J. Chem. Phys.
1992, 96, 6796–6806.
[1] M.-X. Zhang, P. E. Eaton, R. Gilardi, Angew. Chem. 2000, 112, 422–
426; Angew. Chem. Int. Ed. 2000, 39, 401–404.
[2] G. H. Tao, B. Twamley, J. M. Shreeve, J. Mater. Chem. 2009, 19,
5850–5854.
[30] T. H. Dunning, Jr., J. Chem. Phys. 1989, 90, 1007–1023.
[31] K. A. Peterson, D. E. Woon, T. H. Dunning, Jr., J. Chem. Phys.
1994, 100, 7410–7415.
[32] N. Fischer, T. M. Klapçtke, S. Rappenglꢀck, J. Stierstorfer, Chem-
PlusChem 2012, DOI: 10.1002/cplu.201200136.
[33] A. J. Bracuti, Acta Crystallogr. Sect. B 1979, 35, 760–761.
[34] T. M. Klapçtke, J. Stierstorfer, B. Weber, Inorg. Chim. Acta 2009,
362, 2311–2320.
[3] D. E. Chavez, M. A. Hiskey, D. L. Naud, D. Parrish, Angew. Chem.
2008, 120, 8431–8433; Angew. Chem. Int. Ed. 2008, 47, 8307–8309.
[4] O. S. Bushuyev, P. Brown, A. Maiti, R. H. Gee, G. R. Peterson, B. L.
Weeks, L. J. Hope-Weeks, J. Am. Chem. Soc. 2012, 134, 1422–1425.
[5] M. H. V. Huynh, M. A. Hiskey, D. E. Chavez, D. L. Naud, R. D. Gi-
lardi, J. Am. Chem. Soc. 2005, 127, 12537–12543.
[6] B. Lachance, A. Y. Renoux, M. Sarrazin, J. Hawari, G. I. Sunahara,
Chemosphere 2004, 55, 1339–1348.
Chem. Asian J. 2013, 8, 148 – 159
158
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemasianj.org
Thomas M. Klapçtke et al.
[35] T. M. Klapçtke, D. G. Piercey, F. Rohrbacher, J. Stierstorfer, Z.
Anorg. Allg. Chem. 2012, DOI: 10.1002/zaac.201200363.
[36] T. Altenburg, T. M. Klapçtke, A. Penger, J. Stierstorfer, Z. Anorg.
Allg. Chem. 2010, 636, 463–471.
[37] P. J. Linstrom and W. G. Mallard, Eds., NIST Chemistry WebBook,
NIST Standard Reference Database Number 69, National Institute
of Standards and Technology, Gaithersburg MD, 20899, http://web-
book.nist.gov, (retrieved October 27, 2011).
[44] Impact: Insensitive, >40 J; less sensitive, ꢃ35 J; sensitive, ꢃ4 J;
very sensitive, ꢄ3 J. Friction: Insensitive, >360 N; less sensitive=
360 N; sensitive, <360 N and >80 N; very sensitive, ꢄ80 N; ex-
tremely sensitive, ꢄ10 N. According to the UN Recommendations
on the Transport of Dangerous Goods.
[45] CrysAlisPro, Agilent Technologies, Version 1.171.35.11, 2011.
[46] G. M. Sheldrick, SHELXS-97, Program for Crystal Structure Solu-
tion, Universitꢈt Gçttingen, 1997.
[38] a) H. D. B. Jenkins, H. K. Roobottom, J. Passmore, L. Glasser,
Inorg. Chem. 1999, 38, 3609–3620; b) H. D. B. Jenkins, D. Tudela, L.
Glasser, Inorg. Chem. 2002, 41, 2364–2367.
[47] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, Appl.
Crystallogr. 1993, 26, 343.
[48] G. M. Sheldrick, Shelxl-97, Program for the Refinement of Crystal
Structures, University of Gçttingen, Germany, 1994.
´
[39] M. Suceska, EXPLO5.05 program, Zagreb, Croatia, 2012.
´
[40] M. Suceska, Propellants Explos. Pyrotech. 1991, 16, 197–202.
[49] A. L. Spek, Platon, A Multipurpose Crystallographic Tool, Utrecht
University, Utrecht, The Netherlands, 1999.
[50] L. Farrugia, J. Appl. Crystallogr. 1999, 32, 837–838.
[51] Empirical absorption correction using spherical harmonics, imple-
mented in SCALE3 ABSPACK scaling algorithm (CrysAlisPro
Oxford Diffraction Ltd., Version 171.33.41, 2009).
[41] R. Mayer, J. Kçhler, A. Homburg, Explosives, 5th ed., Wiley-VCH,
Weinheim, 2002.
[42] R. M. Vrcelj, J. N. Sherwood, A. R. Kennedy, H. G. Gallagher, T.
Gelbrich, Cryst. Growth Des. 2003, 3, 1027.
[43] Calculation
of
oxygen
balance:
W
(%)=(wOꢀ2xCꢀ1/
2yHꢀ2zS)1600M. (w: number of oxygen atoms, x: number of
carbon atoms, y: number of hydrogen atoms, z: number of sulfur
atoms, M: molecular weight).
Received: September 27, 2012
Published online: November 21, 2012
Chem. Asian J. 2013, 8, 148 – 159
159
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim