New energetic polynitrotetrazoles

Article abstract of DOI:10.1002/chem.201405659

This combined experimental, theoretical and comparative study details the syntheses and chemical characterisation of two new energetic polynitromethyl tetrazole derivatives, namely, 2-(2-nitro-2-azapropyl)-5-(trinitromethyl)-2H-tetrazole and its fluorine-containing analogue 2-(2-nitro-2-azapropyl)-5-(fluorodinitromethyl)-2H-tetrazole. Their crystal structures and energetic behaviour are compared to those of their starting materials, the ammonium salts of the corresponding 5-(polynitromethyl)-2H-tetrazoles. Additionally, the crystal structures of two further related polynitrotetrazoles are presented.

Full text of DOI:10.1002/chem.201405659

DOI: 10.1002/chem.201405659
Full Paper
&
Energetic Materials
New Energetic Polynitrotetrazoles
Marcos A. Kettner and Thomas M. Klapçtke*[a]
Abstract: This combined experimental, theoretical and
comparative study details the syntheses and chemical char-
acterisation of two new energetic polynitromethyl tetrazole
derivatives, namely, 2-(2-nitro-2-azapropyl)-5-(trinitromethyl)-
Their crystal structures and energetic behaviour are com-
pared to those of their starting materials, the ammonium
salts of the corresponding 5-(polynitromethyl)-2H-tetrazoles.
Additionally, the crystal structures of two further related
polynitrotetrazoles are presented.
2H-tetrazole
and
its
fluorine-containing
analogue
2-(2-nitro-2-azapropyl)-5-(fluorodinitromethyl)-2H-tetrazole.
getic polymers based on tetrazoles.[11] Moreover tetrazole de-
rivatives with perfluorinated alkyl groups were investigated as
ingredients in MTV (magnesium, teflon, viton) decoy flares.[12]
The trinitromethyl and fluorodinitromethyl functionalities
have proven to be useful functional groups in the synthesis of
high-performing explosives as well as novel oxidisers for high-
tech propellants.[13] The combined high nitrogen and oxygen
contents of this group allow full oxidation of fuels within the
molecule leading to high performances. Additionally, the large
dipole moment within the nitro and fluorine groups gives rise
to extensive inter- and intramolecular interactions resulting in
high densities, which also affect the performance
advantageously.[14]
Introduction
Polynitroazoles are important and common compounds in
energetic materials research.[1] The design of new materials
includes strategies based on tetrazoles,[2] triazoles,[3] fura-
zanes,[4] N-oxides,[5] furoxanes[6] and tetrazines.[7] Their high
nitrogen contents lead to large amounts of N2 during combus-
tion causing high detonation velocities and pressures.[1] Tetra-
zole derivatives are of special interest owing to the highest
nitrogen content of these five-membered heterocycles
(Scheme 1). 5-substituted tetrazoles are easily accessible
The syntheses of 5-trinitromethyl- and 5-fluorodinitromethyl-
2H-tetrazole and some of their salts were first published in
1981 by Grakauskas et al.[15] and Fokin et al.,[16] respectively.
They used the corresponding polynitroacetonitriles[17] for the
1,3-dipolar ring-closure reaction with trimethylsilyl azide or
sodium azide. However, all starting materials are hazardous
chemicals. A more convenient and “greener” route to the trini-
tromethyl derivative was introduced by Christe and Haiges in
2013 by decarboxylative nitration of the corresponding methyl
carboxylic acid furnishing high yields.[18] Owing to their high
oxygen content these compounds can be considered as solid
oxygen carriers in solid rocket propellants, replacing or partial-
ly replacing currently used ammonium perchlorate (AP).[1] AP
has been identified as toxic to humans thyroid gland[19] and
amphibians.[20] Additionally, the decomposition product hydro-
gen chloride, which is produced in large amounts during
a rocket launch, is environmentally critical.[21] This visible and
detectable expulsion affects guidance systems adversely, and is
also unfavourable for tactical missiles.[22]
Scheme 1. Some examples of five-substituted polynitromethyl- and
polyfluoromethyl-tetrazole derivatives.
through treatment of organic nitriles with sodium azide.[8] Sev-
eral derivatives with oxygen-containing moieties such as nitro
groups, nitrate esters or nitramines at the 5-position were in-
vestigated within our group and are suitable for various ener-
getic applications. For instance, derivatives of 5-nitro-[9] and 5-
nitriminotetrazoles[10] for gas-generating applications, or ener-
[a] M. A. Kettner, Prof. Dr. T. M. Klapçtke+
Department of Chemistry
Ludwig-Maximilian University of Munich (LMU)
Butenandtstrasse 5–13, House D
81377 Munich (Germany)
However, the very high mechanical sensitivities of 5-trinitro-
methyl- and 5-fluorodinitromethyl-2H-tetrazole and their salts
make these compounds inoperable concerning agitation and
processing of propellant formulations. The alkylation described
in this work was carried out to overcome some problematic
issues of the known polynitromethyl tetrazole derivatives:
E-mail: tmk@cup.uni-muenchen.de
[+] Parts of this work have been presented at the 17th seminar “New Trends in
Research of Energetic Materials” in Pardubice (Czech Republic).[59]
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/chem.201405659.
Chem. Eur. J. 2015, 21, 1 – 12
1
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
1) the acidities associated with cyclic nitroazoles, 2) their low
thermal stabilities and 3) their very high sensitivities towards
impact and friction. As known from other 5-substituted tetra-
zole derivatives the methylation can significantly lower the
sensitivities.[9,10] However, to maintain the energetic character
and by trying to keep the oxygen balance as high as possible,
the secondary nitramine moiety was chosen to be incorpor-
ated to these tetrazoles.[23]
He) in anhydrous acetonitrile at ambient temperature in
a closed vessel. Fluorodinitroacetonitrile (5)[17] was not isolated
due to its high volatility. When the reaction mixture turned col-
ourless, the solution containing compound 5 was distilled into
a cooling trap (ꢀ788C) and compound 5 was identified by
multinuclear NMR measurements from the acetonitrile solu-
tion. Subsequently, sodium azide was added to the solution
and the reaction mixture was stirred at ambient temperature
in a closed vessel.[16] The progress of the 1,3-dipolar ring-clo-
sure reaction was monitored by 19F NMR spectroscopy. After an
acidic workup and treatment with aqueous ammonia (25%)
ammonium 5-(fluorodinitromethyl)-2H-tetrazolate (6) was iso-
lated in acceptable yields of 32% (two steps from compound
4). If trimethylsilyl azide is used instead of sodium azide as
known from the literature,[15] with heating the risk of the
formation of undesired side products including azidodinitro
acetonitrile (7) is given. In fact, 19F NMR experiments out of
this reaction mixture confirmed the generation of more than
three species even without heating, and ring closing reactions
were continued with sodium azide. The alkylation reactions of
compounds 3 and 6 were performed with 2-nitro-2-azapropyl
chloride (8)[29] in anhydrous acetone, furnishing the according
2-(2-nitro-2-azapropyl)-5-(polynitromethyl)-2H-tetrazoles 9 and
10 as colourless crystalline solids in good yields of 78% each.
Compounds 3 and 6 were alkylated exclusively in the b-posi-
tion of the tetrazole ring. During the work with compound 3
also crystals of dipotassium 5-(dinitromethylide)-tetrazolate
(11)[30] were isolated from the reaction of compound 3 with
concentrated aqueous potassium hydroxide solution. The
conversion of compound 3 with aqueous hydroxylamine and
hydrazine to the corresponding dinitromethylide salts has
been reported previously.[18]
Results and Discussion
Syntheses
All syntheses described in this work start from commercially
available ethyl 2-cyanoacetate (1) (Scheme 2). Ammonium
5-(trinitromethyl)-2H-tetrazolate (3) was synthesised according
to the literature-known procedure by decarboxylative nitration
of ethyl 2-(1H-tetrazol-5-yl)acetate (2) furnishing high
yields.[18,24,25]
NMR spectroscopy
Compounds 6 and 9–11 were investigated by multinuclear
NMR spectroscopy in [D6]acetone (Table 1). The chemical shifts
of the methyl and methylene groups in compounds 9 and 10
are observed in the expected ranges of d=3.69 and 6.98 ppm
1
in the H NMR spectrum, and at d=38.6 and 67.5 ppm in the
13C NMR spectrum. The 13C signals of the tetrazole carbon
atoms are shifted to d=152.3 ppm for compound 9, to d=
150.8 ppm for compound 6 with a J(C,F) coupling constant of
Scheme 2. All syntheses described in this work started from ethyl 2-cyano-
acetate (1). 1,3-Dipolar ring-closure and saponification yielding compound 2
were carried out according to references [24] and [25]. The nitration yielding
compound 3 was performed according to reference [18]. The synthesis of
compound 4 from compound 1 was carried out according to referen-
ces [26]–[28]. Synthesis of compound 5 was performed with Selectfluor
(F-TEDA) in acetonitrile without isolation, and subsequent 1,3-dipolar ring
closure yielding compound 6 was carried out according to reference [16].
Syntheses of compounds 9 and 10 were performed in anhydrous acetone.
TMS=trimethylsilyl.
2
Table 1. Chemical shifts d [ppm] of compounds 6 and 9–11.
Nucleus
1H
Assignment
6
9
10
3.68
6.96
38.6
11
CH3
CH2
CH3
CH2
–
–
–
–
3.70
–
–
–
7.00
38.6
67.6
121.2
152.3
ꢀ33
ꢀ37
–
13C
67.3
–
[a]
C(NO2)nFm
119.9 (d)[b]
150.8 (d)
–
ꢀ20.6(d)*[c]
115.4 (d)
153.7 (d)
ꢀ32
128.5
155.2
–
ꢀ23
–
CTz
Ammonium 5-(fluorodinitromethyl)-2H-tetrazolate (6) was
synthesised according to a slightly modified literature proce-
dure from potassium dinitroacetonitrile (4).[16,26–28] Differing
from the literature the fluorination of potassium dinitroacetoni-
trile (4) was performed with Selectfluor (instead of 25% F2 in
14N
19F
NNO2
CNO2
CF
ꢀ27 (d)
ꢀ95.5
ꢀ99.6
[a] n=2, 3; m=0, 1. [b] d=doublet. [c] *=15N NMR spectroscopy.
&
&
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
2
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
2
23.0 Hz and to d=153.7 ppm for compound 10 with a J(C,F)
Table 2. IR and Raman vibrations [cmꢀ1] of compounds 9 and 10.
coupling constant of 25.4 Hz. The signals of the polynitro
carbon atoms are shifted to d=121.2 ppm for compound 9, to
d=119.9 ppm for compound 6 with a 1J(C,F) coupling constant
Vibration
9
10
IR
Raman
IR
Raman
1
of 284.7 Hz and to 115.4 ppm for compound 10 with a J(C,F)
3068
3007
2883
1468
1447
1420
1540
1258
1598
1299
–
3069
3008
2890
1421
3050
3004
2966
1460
1427
3051
3004
2970
1466
1436
coupling constant of 282.9 Hz.[31] Compound 11 was identified
on the basis of the literature-known 13C NMR chemical shifts.[30]
In the 14N NMR spectra the signals of the nitro groups at the
nitramine moiety are observed at d=ꢀ33 ppm for compound
9 and at d=ꢀ32 ppm for compound 10. The signals of the
polynitro groups are shifted to d=ꢀ37 ppm for compound 9
n(CH2/CH3)
d(CH2)
nas(NO2)
ns(NO2)
1540
1260
1607
1304
–
1536
1260
1595
1304
1260
–
1552
1276
1590
1304
1276
1503
nas(NꢀNO2)
ns(NꢀNO2)
n(CꢀF)
2
and to d=ꢀ27 ppm for compound 10 with a J(C,F) coupling
constant of 10 Hz.[32]
For compound 6 a 15N NMR spectrum was recorded. It
shows the signal for the fluorodinitro group shifted to d=
ꢀ20.6 ppm as a doublet (2J(15N,F)=16.5 Hz), and additionally
the signals for the nitrogen atoms of the tetrazole ring
(d(Na)=9.6, d(Nb)=ꢀ57.5 ppm). The nitrogen NMR signal of
the ammonium cation is found at d=ꢀ362.2 ppm. In the
19F NMR spectrum the fluorine signal of compound 6 is ob-
served at d=ꢀ95.5 and the signal of compound 10 is found
at d=ꢀ99.6 ppm, both as broad singlets indicating multiplets.
The intermediate fluorodinitroacetonitrile (5), which was not
isolated, was identified by 14N and 19F NMR spectroscopy from
the acetonitrile solution (Figure 1). The 14N NMR spectrum
n(C=N)
–
1487
Raman spectrum additionally shows the stretching vibration of
the C=N bond at n˜ =1487 cmꢀ1
.
The IR spectrum of compound 10 displays the stretching vi-
brations of the CH2/CH3 groups in the range of n˜ =3050–
2966 cmꢀ1. The absorption bands in the range of n˜ =1460–
1427 cmꢀ1 can be assigned to the deformation vibrations of
the CH2/CH3 groups. At n˜ =1536 and 1260 cmꢀ1 the
asymmetric and symmetric stretching vibrations of the nitro
groups in the fluorodinitromethyl moiety can be observed. The
nitramine moiety shows the asymmetric stretching vibration at
n˜ =1595 cmꢀ1 and the symmetric stretching vibration
at n˜ =1304 cmꢀ1. The CꢀF stretching vibration is observed at
n˜ =1260 cmꢀ1. The Raman spectrum additionally shows the
stretching vibration of the C=N bond at n˜ =1503 cmꢀ1
.
X-ray diffraction
Single crystals suitable for low-temperature X-ray diffraction
measurements were obtained from a toluene/ethyl acetate
(1:1) mixture for compound 6, and from a methanol/dichloro-
methane (1:1) mixture for compounds 9 and 10. Compound
11 crystallised from an aqueous KOH solution. All relevant
crystallographic and structural refinement data are listed in
Table 3.
Figure 1. NMR spectra of compound 5. Left) 19F NMR spectrum,
2
2J(F,14N)=11 Hz. Right) 14N NMR spectrum, J(14N,F)=11 Hz.
shows the signal of the two nitro groups at d=ꢀ37 ppm as
2
a doublet due to a J(14N,F) coupling of 11 Hz. In the 19F NMR
spectrum the signal is observed at d=ꢀ93.3 ppm, spitted into
a quintet due to coupling with two 14N nuclei (2J(F,14N)=
11 Hz).
Ammonium
5-(fluorodinitromethyl)-2H-tetrazolate
(6)
crystallises in the monoclinic space group P21/c with eight
formulas per unit cell and a calculated maximum density of
1.747 gcmꢀ3 at 113 K (Figure 2). The structure displays two
crystallographically independent 5-(fluorodinitromethyl)-2H-
tetrazolate anions and ammonium cations in the asymmetric
unit. In the anions the CꢀF bond lengths are slightly shorter
than the common single CꢀF bond length (1.36 ꢁ). The CꢀNO2
bond lengths are elongated as compared to the average value
of a single CꢀN bond length (1.47 ꢁ).[34]
Vibrational spectroscopy
Compounds 9 and 10 were also investigated by IR and Raman
spectroscopy (Table 2).[33] The IR spectrum of compound 9
shows the stretching vibrations of the CH2/CH3 groups in the
range of n˜ =3068–2883 cmꢀ1. The absorption bands in the
range of n˜ =1468–1420 cmꢀ1 can be attributed to the defor-
mation vibrations of the CH2/CH3 groups. At n˜ =1540 and
1258 cmꢀ1 the asymmetric and symmetric stretching vibrations
of the trinitromethyl moiety are observed. The nitramine unit
shows the asymmetric stretching vibration at n˜ =1598 cmꢀ1
and the symmetric stretching vibration at n˜ =1299 cmꢀ1. The
The average NꢀO bond lengths and O-N-O angles are in the
range of common nitro groups.[34] The CꢀC bond lengths are
in between the common single (1.54 ꢁ) and double bond
(1.33 ꢁ).[34] The bond lengths and angles within the five-mem-
bered rings are in the expected range.[18] It is remarkable that
the C-C-N-O torsion angles of both molecules (C2-C1-N1-O3
ꢀ72.4(1)8, C2-C1-N2-O1 3.3(1)8, C4-C3-N8-O7 71.8(2)8, C4-C3-
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
3
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
The solid state structure of
compound 6 consists of ammo-
nium cations and 5-(fluorodini-
tromethyl)-2H-tetrazolate anions
that are associated through clas-
sical hydrogen bonds (Figure 4).
They are observed between N13
and N3 (N13ꢀH3 0.93(2) ꢁ,
Table 3. Crystallographic data of compounds 6 and 9–11.
Compound
6
9
10
11
sum formula
C2H4N7O4F
209.10
0.30ꢂ0.10ꢂ0.05
colourless needles
monoclinic
P21/n
14.0080(7)
8.9900(7)
13.9790(4)
90.0
115.397(8)
1590.27(15)
8
C4H5N9O8
307.17
0.40ꢂ0.19ꢂ0.08
colourless plates
orthorhombic
Pbca
5.9400(5)
18.6730(13)
20.4840(13)
90.0
90.0
2272.0(3)
8
1.796
0.171
C4H5N8O6F
280.13
0.30ꢂ0.16ꢂ0.09
colourless needles
monoclinic
P21/n
5.8497(3)
15.2996(8)
11.1992(5)
90.0
97.003(4)
994.83(8)
4
1.870
0.182
568
100(2)
4.15–26.00
ꢀ7ꢁhꢁ7
ꢀ18ꢁkꢁ18
ꢀ13ꢁlꢁ12
7248
1933
1658
0.0231
0.0270, 0.0613
0.0338, 0.0651
1933/0/192
1.035
ꢀ0.215/0.314
0.0282, 0.3097
K2C2N6O4
250.28
0.40ꢂ0.06ꢂ0.05
yellow rods
orthorhombic
Pbcn
9.1698(3)
9.0743(3)
9.2617(4)
90.0
90.0
770.66(5)
4
2.157
1.230
formula weight [gcmꢀ3
]
crystal dimensions [mm3]
crystal description
crystal system
space group
a [ꢀ]
b [ꢀ]
c [ꢀ]
H3···N3
2.02(2) ꢁ,
N13···N3
2.918(3) ꢁ, N13-H3···N3 164.1(1)8),
and between N14 and O2 (N14ꢀ
H8 0.89(2) ꢁ, H8···O2 2.82(2) ꢁ,
N14···O2 3.189(3) ꢁ, N14-H8···O2
106.8(1)8). In addition typical
electrostatic interactions be-
tween the nitro groups are ob-
served (Figure 4). The N2···O1(i)
short contact (3.029(2) ꢁ) be-
tween the nitro groups is slightly
under the sum of the van der
Waals radii (ꢀ(van der Waals
radii): O···N 3.07 ꢁ).[36] The fluo-
rine atoms also form intermolec-
ular short contacts with distan-
ces below the van der Waals
radii (F1···O5 2.870(2) ꢁ, F2···O2i
2.853(3) ꢁ; symmetry operator
a and g [8]
b [8]
V [ꢁ3]
Z
1calcd [gcmꢀ3
]
1.747
0.173
848
m [mmꢀ1
F(000)
]
1248
496
100(2)
temperature [K]
113(2)
100(2)
q range [8]
4.12–25.50
ꢀ16ꢁhꢁ16
ꢀ10ꢁkꢁ10
ꢀ16ꢁlꢁ16
13072
2915
2485
0.0325
4.11–26.00
ꢀ7ꢁhꢁ6
ꢀ23ꢁkꢁ23
ꢀ25ꢁlꢁ25
16301
2205
1762
0.0510
4.40–25.98
ꢀ7ꢁhꢁ11
ꢀ11 ꢁkꢁ11
ꢀ11 ꢁlꢁ11
3577
749
651
0.0271
0.0218, 0.0486
0.0284, 0.0517
749/0/65
1.098
ꢀ0.239/0.351
0.0195, 0.3762
index ranges
reflections measured
reflections independent
reflections unique
Rint
R1, wR2 (2s data)
R1, wR2 (all data)
data/restraints/parameters
GoF on F2
0.0280, 0.0600
0.0359, 0.0639
2915/0/285
1.026
0.0368, 0.0857
0.0502, 0.0938
2205/0/210
1.038
residual electron density
weighting scheme[a]
ꢀ0.179/0.271
0.0312, 0.5670
ꢀ0.160/0.239
0.0460, 0.6430
1
1
i =x, = ꢀy, ꢀ = +z; ꢀ(van der
2
2
Waals radii): O···F 2.99 ꢁ).[36]
[a] wR2 =[S[w(F20ꢀFc2)2]/S [w(F0)2]]1/2 where w=[s2c(F20)+(xP)2+yP] and P=(F02+2F2c)/3.
2-(2-Nitro-2-azapropyl)-5-(trini-
tromethyl)-2H-tetrazole (9) crys-
N7-O6 ꢀ15.6(2)8) are not in the typical range for the propeller-
like conformation of polynitromethyl moieties (23–678) de-
scribed by Brill et al.,[35] but the nitro groups are rotated syn.
However, this orientation results in intramolecular interactions
with N···O, F···O and F···N distances well below the sum of the
van der Waals radii as depicted in Figure 3.[36]
tallises in the orthorhombic space group Pbca with eight mole-
cules in the unit cell and a calculated maximum density of
1.796 gcmꢀ3 at 100 K (Figure 5).
The C1ꢀC2 bond length with 1.488(2) ꢁ is shorter than
a common CꢀC single bond (1.54 ꢁ).[34] The C2ꢀN bonds to
the nitro groups are slightly elongated (1.523–1.544 ꢁ). The Nꢀ
O bond lengths of all nitro groups are in the expected range
(1.208–1.227 ꢁ). The trinitromethyl group arranges into the
typical propeller-like orientation as found in many trinitrometh-
yl-containing compounds with intramolecular short contacts
Figure 2. Asymmetric unit in the crystal structure of compound 6. Selected
bond lengths [ꢁ] and angles [8]: N1ꢀO3 1.219 (2), N1ꢀO4 1.210 (2), N2ꢀO1
1.208(2), N2ꢀO2 1.227(2), C1ꢀC2 1.481(3), C3ꢀC4 1.478(2), C1ꢀF1 1.337(2),
C3ꢀF2 1.328(3), C1ꢀN1 1.539(2), C1ꢀN2 1.544(2), C2ꢀN3 1.334(2), C2ꢀN6
1.335(2), N3ꢀN4 1.343(2), N4ꢀN5 1.323(1), N5ꢀN6 1.342(2); O1-N2-O2
127.7(1), O3-N1-O4 127.5(1), O1-N2-C1 117.4(1), O2-N2-C1 115.1(1), N1-C1-F1
108.0(1), N2-C1-F1 105.6(1), N1-C1-N2 103.6(1), F1-C1-C2 113.3(1), N3-C2-C1
124.7(1), N4-N5-N6-C2 0.0(1).
Figure 3. Views along the C1ꢀC2 (left) and C3ꢀC4 (right) bonds of com-
pound 6 illustrating the geometry of the fluorodinitromethyl groups with its
intramolecular interactions (dashed lines): F1···O2 2.637(2), F1···O4 2.544(2),
F2···O5 2.567(2), F2···O8 2.517 ꢁ, F1···N1 2.329(2), F1···N2 2.298(2) ꢁ, F2···N7
2.301(2), F2···N8 2.320(2) ꢁ, N1···O2 2.796(2), N2···O3 2.683(2), N7···O7
2.694(3), N8···O5 2.901(3) ꢁ. ꢀ(van der Waals radii): F···O 2.99 ꢁ, N···O 3.07 ꢁ,
F···N 3.02 ꢁ.[36]
&
&
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
4
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
Figure 6. Strong hydrogen bonds presented by dashed lines in the crystal
structure of compound 9 for the structural parameters given in Table 4.
Figure 4. Hydrogen bonds (gray dashed lines) and electrostatic interactions
(black dashed lines) in the crystal structure of compound 6. Symmetry
operator: ’=x, 1ꢀy, 1ꢀz.
Figure 7. Molecular structure of compound 10 in the crystal. Selected bond
lengths [ꢁ] and angles [8]: C1ꢀC2 1.492(2), F1ꢀC2 1.313(2), N6ꢀC2 1.557(2),
N5ꢀC2 1.551(2), N7ꢀN8 1.363(1), N3ꢀN4 1.321(2), O3ꢀN5 1.208(2), O2ꢀN6
1.210(2), O5ꢀN8 1.234(1), N7ꢀC3 1.461(2), N2ꢀC4 1.486(2); O4-N5-O3
127.7(1), C4-N7-C3 123.0(1), C4-N7-N8 116.6(1), N4-C1-C2-F1 0.4(1), C1-C2-
N6-O2 53.6(2), O3-N5-C2-C1 59.9(1).
Figure 5. Molecular structure of compound 9 in the crystal. Selected bond
lengths [ꢁ] and angles [8]: C1ꢀC2 1.488(2), N5ꢀC2 1.523(2), N6ꢀC2 1.538(2),
N7ꢀC2 1.544(2), O1ꢀN5 1.208(1), O3ꢀN6 1.213(2), O6ꢀN7 1.210(2), N3ꢀN4
1.316(2) N8ꢀN9 1.366(2), O7ꢀN9 1.227(2); N2-C4 1.471(2); O4-N6-O3
127.7(2), C4-N8-C3 122.5(2), C4-N8-N9-O7 -6.9(2), O1-N5-C2-C1 62.4(2),
O4-N6-C2-C1 40.8(2), O6-N7-C2-C1 39.2(2).
2-(2-Nitro-2-azapropyl)-5-(fluorodinitromethyl)-2H-tetrazole
(10) crystallises in the monoclinic space group P21/n with four
molecules in the unit cell and a calculated maximum density
of 1.870 gcmꢀ3 at 100 K (Figure 7).
well below the sum of the van der Waals radii.[37,38] This is also
reflected in the torsion angles (O1-N5-C2-C1 62.4(2)8, O4-N6-
C2-C1 40.8(2)8, O6-N7-C2-C1 39.2(2)8), which are in the range
for this propeller-like structure of polynitromethyl moieties de-
scribed by Brill et al. (23–678).[35,37,38] The structure is mainly
build up by multiple hydrogen bonds, whereby all hydrogen
atoms participate and connect one molecule to six of its
neighbours (Table 4, Figure 6).
The C1ꢀC2 bond is shorter than a common CꢀC single bond
(1.54 ꢁ)[34] but with 1.492(2) ꢁ it is slightly elongated in com-
parison to the corresponding bond in the analogous com-
pound 9. The C2ꢀF1 bond is slightly shorter (1.313(2) ꢁ) than
common CꢀF bonds (1.36 ꢁ).[34] The C2ꢀN bonds to the nitro
groups are elongated (1.551(2) and 1.557(2) ꢁ). The NꢀO bond
lengths of the nitro groups (1.208–1.212 ꢁ) are between those
of common single and double NꢀO bonds (1.45 and 1.17 ꢁ, re-
spectively).[34] Differing from the starting material 6 the orienta-
tion of the fluorodinitromethyl moiety shows the propeller-like
conformation, here with C1-C2-N-O torsion angles (C1-C2-N5-
O3 ꢀ59.9(2)8, C1-C2-N6-O2 53.6(1)8) in the typical range for
the propeller-like structure (23–678) as described by Brill
et al.[35] The fluorine atom strongly stabilises this orientation by
interacting with the oxygen and the nitrogen atoms of the
nitro groups. Also the N···O distances between the nitro
groups are clearly under the ꢀ(van der Waals radii) (dashed
lines in Figure 8).[36]
Table 4. Structural parameters of the hydrogen bonds in the crystal of
compound 9 presented in Figure 6.[a]
DꢀH···A
d(DꢀH) [ꢁ] d(H···A) [ꢁ] d(DꢀH···A) [ꢁ] ](D-H···A) [8]
C3ꢀH31···O8’
C4ꢀH41···O7’
C3ꢀH33···O8’’
C3ꢀH32···O6’’’
0.95(2)
0.95(2)
0.94(2)
0.95(3)
2.54(2)
2.50(2)
2.58(2)
2.57(2)
2.39(2)
3.479(3)
3.348(2)
3.307(3)
3.501(2)
3.084(3)
167.3(9)
149.5(5)
133.6(8)
167.1(1)
130.7(5)
C4ꢀH42···O7’’’’ 0.94(2)
1
1
[a] Symmetry operators: ’=ꢀ1+x, y, z; ’’=ꢀ = +x, = ꢀy, ꢀz; ’’’=1ꢀx, ꢀy,
2
2
The structure of compound 10 is build up by extensive
hydrogen bonding. Similar to compound 9 all hydrogen
1
ꢀz; ’’’’=ꢀ = +x, y, 1= ꢀz.
2
2
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
5
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
Figure 8. View along the C2ꢀC1 bond of compound 10 illustrating the ge-
ometry of the fluorodinitromethyl group with its intramolecular interactions:
F1···O4 2.480(1), F1···O1 2.481(1) ꢁ, F1···N5 2.315(1), F1···N6 2.315(2) ꢁ, N5···O2
2.941(1), N6···O3 2.883(1) ꢁ. ꢀ(van der Waals radii): F···O 2.99, F···N 3.02, N···O
3.07 ꢁ.[36]
Figure 10. Molecular structure of compound 11 in the crystal. Selected atom
distances [ꢁ], bond lengths [ꢁ] and angles [8]: K1···O2 2.997(2), K1···O2’
2.903(2); C1ꢀC2 1.463(4), C1ꢀN1 1.337(2), N1ꢀN2 1.344(3), C2ꢀN3 1.384(1),
N3ꢀO1 1.264(2), N3ꢀO2 1.250(1); O2-K1-O2’ 52.08(2), K1-O2-K1’ 100.98(3),
O1-N3-O2 120.2(1), O2-N3-C2 123.4(1), O1-N3-C2 116.4(2), N3-C2-N3’
120.8(1), O1-N3-C2 116.4(1), N1-C1-N1’ 111.9(1), N1-C1-C2-N3’ 93.5(2),
1
N1-C1-C2-N3 ꢀ86.5(2). Symmetry operator ’=1= ꢀx, ꢀ = +y, z.
atoms participate in those hydrogen bonds and connect one
molecule to eight of its neighbours (Table 5, Figure 9).
Differing from compound 9 the tetrazole rings are arranged
parallel to each other.
2
2
C2 bond length of 1.449(1) ꢁ,[18] in the structure of compound
11 the dinitromethyl moiety is rotated out of the tetrazole
plane with a torsion angle of N1-C1-C2-N3’=93.5(2)8 and
a C1ꢀC2 bond length of 1.463(4) ꢁ. This indicates, that the
negative charge of the dinitromethyl group is not delocalised
into the tetrazole ring. The C1ꢀC2 bond length in the structure
of the free acid dihydro-(dinitromethylene)-tetrazole is even
shorter with 1.418(2) ꢁ and the molecule is completely
Dipotassium 5-(dinitromethylide)-tetrazolate (11) crystallises
as yellow rods in the orthorhombic space group Pbcn with
four formulas per unit cell and a calculated maximum density
of 2.157 gcmꢀ3 at 100 K (Figure 10). To the best of our knowl-
edge, only the structure of the monopotassium salt is known
so far,[18] which mainly differs in the orientation of the dinitro-
methyl group relative to the five-membered ring. Whereas in
the monopotassium salt the anion is almost planar with a C1ꢀ planar.[39]
The crystal structure is mainly build up by one repetitive
motif illustrated in Figure 11. It forms chains along the b axis
that run in both directions and in which the molecules are
rotated by 908 with respect to each other. Every nitrogen
atom of the ring and all oxygen atoms of the nitro groups
are involved in ionic contacts to the potassium cations with
distances ranging between 2.750(1) and 2.830(2) ꢁ.
Table 5. Structural parameters of the hydrogen bonds in the crystal of
compound 10 presented in Figure 9.[a]
DꢀH···A
d(DꢀH) [ꢁ] d(H···A) [ꢁ] d(DꢀH···A) [ꢁ] ](D-H···A) [8]
C4ꢀH42···O5’
C4ꢀH42···O6’
C3ꢀH33···O6’
C4ꢀH41···O5’’
0.98(2)
0.98(2)
0.97(2)
0.95(1)
2.50(2)
2.57(2)
2.47(2)
2.41(2)
2.64(1)
2.69(2)
2.70(2)
2.66(2)
3.287(1)
3.479(2)
3.382(2)
3.270(2)
3.239(1)
3.460(1)
3.264(2)
3.623(2)
137.5(4)
155.0(3)
157.9(5)
150.4(1)
122.0(1)
139.8(2)
117.3(2)
170.4(4)
C4ꢀH41···O2’’’ 0.95(1)
C3ꢀH31···F1’’’’ 0.94(2)
C3ꢀH32···F18
C3ꢀH32···N48
0.98(2)
0.98(2)
[a] Symmetry operators: ’=1+x, y, z; ’’=ꢀx, ꢀy, 1ꢀz; ’’’=1ꢀx, ꢀy, 1ꢀz;
1
1
1
1
’’’’=ꢀ = +x, = ꢀy, = +z; 8=1= ꢀx, ꢀ = +y, 11= ꢀz.
2
2
2
2
2
2
Figure 11. Arrangement of the molecules to form chains along the b axis in
the crystal structure of compound 11. Selected atom distances [ꢁ]: O1···K1
2.750(1), N1···K1 2.774(2), N2···K12.830(2).
Physical, chemical and energetic properties
Owing to the energetic nature of all described compounds 3,
6, 9 and 10 and for initial safety testing their sensitivities and
energetic behaviour were determined. Their investigated phys-
ical and thermodynamic properties are summarised in Table 6.
The sensitivities towards impact and friction were determined
Figure 9. Strong hydrogen bonds represented by dashed lines in the crystal
structure of compound 10 for the structural parameters listed in Table 5.
&
&
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
6
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
and 1.83 gcmꢀ3. The heats of formation were computed by ab
initio calculations by using the Gaussian 09 program
package[45] at the CBS-4M level of theory.[46] All compounds are
formed endothermically with the highest value of
313.9 kJmolꢀ1 calculated for compound 9.
The detonation and combustion parameters of compounds
3, 6, 9 and 10 were computed with the Expo5 computer code
(Version 6.02),[47] based on the calculated heats of formation
and attributed to the corresponding densities at ambient
temperature. The results are listed in Table 7. The detonation
velocities and pressures of all the tetrazole derivatives 3, 6, 9
Table 6. Physical and thermodynamic properties of the alkylated
compounds 9 and 10 in comparison to their starting materials 3 and 6.
Compound
3
9
6
10
formula
C2H4N8O6
236.10
2
8
50
<100
–
128
47.46
88.12
13.5
0.0
1.78
1074.7
231.4
C4H5N9O8
307.17
3
40
100
100–500
87
134
41.04
82.71
7.8
ꢀ13.0
1.75
C2H4N7O4F
209.10
1
16
100
<100
–
166
46.89
77.50
0.0
ꢀ15.3
1.70
126.9
6.7
C4H5N8O6F
280.13
2
36
100
100–500
46
184
40.00
74.27
ꢀ2.9
ꢀ25.7
1.83
weight [gmolꢀ1
impact [J][a]
friction [N][a]
ESD [mJ][b]
]
grain size [mm][c]
Tm [8C][d]
Tdec [8C][e]
N [%][f]
N+O [%][f]
WCO [%][g]
Table 7. Calculated detonation and combustion parameters (EXPLO5,
V6.02)[47] of compounds 3, 6, 9 and 10.
WCO [%][h]
2
1RT [gcmꢀ3
]
[i]
DfU [kJkgꢀ1
DfH8 [kJmolꢀ1
]
1110.8
313.9
439.4
98.3
[j]
Detonation parameters
3
9
6
10
[k]
]
[a]
DExU8 [kJkgꢀ1
]
ꢀ6190
4356
9058
341
ꢀ6016
4291
8704
334
ꢀ5540
3734
8476
299
ꢀ5394
3783
8773
342
Tex [K][b]
[a] Impact and friction sensitivities according to standard BAM meth-
ods.[40] [b] Sensitivity towards electrostatic discharge according to stan-
dard BAM methods.[42] [c] Grain size of the samples used for sensitivity
tests. [d] Melting onset point from DSC measurements carried out at
a heating rate of 58C minꢀ1. [e] Decomposition onset point from DSC
measurements carried out at a heating rate of 58C minꢀ1. [f] Nitrogen
and combined nitrogen and oxygen contents. [g] Absolute oxygen bal-
ance assuming to the formation of CO and HF. [h] Absolute oxygen bal-
ance assuming to the formation of CO2 and HF. The oxygen balance of
ammonium perchlorate is 34.0%. [i] Experimentally determined density
from pycnometer experiments (average value from three measurements).
[j] Energy of formation calculated at the CBS-4M level of theory.[46]
[k] Heat of formation calculated at the CBS-4M level of theory.[46]
[c]
DV [msꢀ1
]
pCJ [kbar][d]
V0 [Lꢀ1 kgꢀ1
[e]
]
826
774
801
728
combustion parameters: oxidiser/aluminium/PBAN [%][f]
Is (neat) [s][g]
270
275
258
260
275
273
274
253
256
269
259
263
244
246
256
259
253
244
246
254
Is (80:20:0) [s][h]
Is (70:16:14) [s][i]
Is (76:10:14) [s][h]
Is (80:13:7) [s][j]
[a] Heat of detonation. [b] Temperature of the explosion gases. [c] Deto-
nation velocity. [d] Detonation pressure. [e] Volume of gaseous detona-
tion products (assuming only gaseous products). [f] Using isobaric com-
bustion conditions at a chamber pressure of 70.0 bar versus ambient
pressure with equilibrium expansion conditions at the nozzle throat.
[g] Specific impulse of the neat compound. [h] Specific impulse of mix-
tures with aluminium and/or PBAN binder. Binder composition 6% poly-
butadiene acrylic acid, 6% polybutadiene acrylonitrile, 2% bisphenol A
ether. [i] Original NASA composition (70:16:14) for the space shuttle solid
rocket boosters.[48] This mixture with AP as oxidiser exhibits a Is of 260 s.
[j] Specific impulse for a composition with 7% PBAN binder.
experimentally according to the standards of the German
Federal Institute for Materials Research and Testing (BAM).[40]
According to the UN recommendations for the transport of
dangerous goods,[41] all compounds shall be classified as “very
sensitive” towards impact, compounds 6, 9 and 10 as “very
sensitive” and compound 3 as “extremely sensitive” towards
friction at the specified grain sizes. The electrostatic discharge
(ESD) test was carried out in order to determine whether the
compounds are ignitable by the human body, which can
generate up to 0.025 J of static energy.[42] It was measured on
a small scale electric spark tester ESD 2010EN (OZM Research)
operating with the Winspark 1.15 software package.[43] All
measured compounds are insensitive towards this energy.
Whereas the ammonium salts 3 and 6 decompose (128 and
1668C) without melting, their alkylated derivatives 9 and 10
show improved decomposition points (134 and 1848C), and
melting points well below 1008C. This fact might be explained
by more hydrogen bonding within the structure and is ob-
served for many compounds containing this secondary nitra-
mine moiety.[23,44] Thus, compounds 9 and 10 show large melt-
ing ranges of 47 and 1388C, respectively. The very high com-
bined nitrogen and oxygen contents ranging from 74.46 to
88.12% might make these compounds interesting for gas-gen-
erating applications. The trinitromethyl derivatives 3 and 9
show positive oxygen balances assuming the formation of
carbon monoxide, as required for oxygen carriers in solid
rocket propellants. The densities as obtained from ambient
temperature pycnometer measurements range between 1.70
and 10 are comparable with those calculated for HMX (1,3,5,7-
tetranitro-1,3,5,7-tetrazaoctane, 9235 msꢀ1
,
388 kbar), RDX
(1,3,5-trinitroperhydro-1,3,5-triazine, 8838 msꢀ1, 343 kbar) and
PETN (pentaerythrithyltetranitrate, 8404 msꢀ1, 309 kbar).[47]
Hence, they are all useful high-performing and oxygen-rich
explosives.
Regarding the combustion in a chamber with 70 bar pres-
sure against atmosphere the trinitromethyl-containing deriva-
tives 3 and 9 show the highest specific impulses as neat com-
pounds as well as in their mixtures with aluminium and/or
polybutadiene acrylonitrile binder (PBAN). Due to their higher
oxygen balances (W) and heats of formation, the Is values are
about 10 s higher than those of the corresponding fluorine-
containing analogues 6 and 10. The Is value of compound 3 in
the original NASA mixture (70:16:14) almost achieves the maxi-
mum value of AP (260 s).[48] The oxidiser/aluminium ratio can
be varied from 70:16 to 76:10, whereas maintaining the PBAN
binder at 14%. With this mixtures (76:10:14) the specific im-
pulses Is values of the trinitromethyl-containing compounds 3
and 9 are in the range of AP; the fluorine-containing materials
6 and 10 improve their Is values only slightly.
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
7
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
FTIR spectrometer equipped with a Smiths DuraSamplIR II ATR
device, Raman spectra were recorded with a Perkin–Elmer 2000
NIR FT spectrometer fitted with a Nd:YAG laser (l=1064 nm). All
NMR spectra were recorded at ambient temperature in [D6]acetone
with a JEOL Eclipse 400 instrument and chemical shifts were deter-
mined with respect to external Me4Si (1H: 399.8 MHz, 13C:
100.5 MHz), MeNO2 (14N: 28.9 MHz, 15N: 40.6 MHz) and CCl3F (19F:
376.5 MHz). Mass spectrometric data were obtained with a JEOL
MStation JMS 700 spectrometer (FABꢂ). Analyses of C/H/N were
performed with an elemental Vario EL analyser.
When reducing the PBAN binder from 14 to 7%, the trinitro-
methyl-containing compounds 3 and 9 achieve considerably
higher specific impulses Is values than 260 s (Table 7). As a rule
of thumb an increase of the value for Is by 20 s leads empirical-
ly to a doubling of the usual carried payload (satellite or war-
head) of a rocket.[1] The Is values of the fluorine-containing ma-
terials 6 and 10 in these mixtures are only about 5 s under the
maximum value of AP of 260 s. However, these compounds
might also be useful for application in agent defeat weapons
owing the assumed toxic fluorine-containing combustion
products.[1]
X-ray diffraction
The dipotassium salt 11 reveals a rather high detonation
velocity of about 9100 msꢀ1 while being thermally stable
until 2808C. With sensitivities (impact: 4J, friction: 144 N, ESD:
100 mJ) in the range of PETN (impact: 4 J, friction: 80 N, ESD:
100 mJ) it might also be a good detonator material with
improved performance and thermal stability compared to
PETN (see the Supporting Information).[49]
For compounds 6 and 9–11, an Oxford Xcalibur3 diffractometer
with a CCD area detector was employed for data collection by
using MoKa radiation (l=0.71073 ꢁ). The data collection was per-
formed by using the Crysalispro software.[50] The structures were
solved by direct methods (SIR2004)[51] and refined by full-matrix
least-squares on F2 (SHELXL-97).[52] All non-hydrogen atoms were
refined anisotropically. The hydrogen atom positions were located
in a difference Fourier map and then refined freely. DIAMOND
plots are shown with thermal ellipsoids at the 50% probability
level.[53] Crystallographic data (excluding structure factors) for the
structures reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary publica-
tion numbers. CCDC 956909 (6), 974783 (9), 974784 (10) and
1026523 (11) 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.
Conclusion
From this combined experimental, theoretical and comparative
study the following conclusions can be drawn:
The alkylation of the 5-substituted tetrazoles is very selective
at the N2 position of the ring.
The alkylation barely affects the impact sensitivity, but the
friction sensitivity gets improved.
The target alkylated compounds have a large melting area
and higher decomposition points than the starting materials,
which have no melting point.
Computational details
All quantum chemical calculations were carried out by using the
program package Gaussian 09, revision C.01,[45a] and visualised by
Gaussview 5, V5.0.8.[45b] The enthalpies (H) and free energies (G)
were calculated by using the complete basis set (CBS) method in
order to obtain accurate values.[46,54] The CBS models use the
known asymptotic convergence of pair natural orbital expressions
to extrapolate from calculations by using a finite basis set to the
estimated complete basis set limit. CBS-4 starts with a HF/3-21G(d)
geometry optimisation, which is the initial guess for the following
SCF calculation as a base energy and a final MP2/6-31+G** calcu-
lation with a CBS extrapolation to correct the energy in second
order. The used re-parameterised CBS-4M method additionally im-
plements a MP4(SDQ)/6-31G calculation to approximate higher
order contributions and also includes some additional empirical
corrections.[45] Solid-state enthalpies and energies of formation
were calculated from the corresponding enthalpy derived from
these quantum chemical CBS-4M calculations (HCBS-4M). Therefore,
the enthalpies of formation of the gas-phase species were comput-
ed according to the atomisation energy method.[55] The solid-state
enthalpies of formation (DfH8) were estimated by subtracting the
gas-phase enthalpies with the corresponding enthalpy of sublima-
tion obtained by the rule of Trouton[56] for the neutral compounds
9 and 10.
Comparing the trinitromethyl compounds with the
fluorodinitromethyl compounds, the latter show slightly lower
sensitivities, higher decomposition points and the alkylated flu-
orine-containing compound shows a much larger melting area
than the alkylated trinitromethyl-containing compound.
The calculated heats of formation for the trinitromethyl-
containing compounds are more endothermic than those of
the fluorine-containing compounds. Moreover, they are higher
endothermic for the corresponding alkylated compounds.
The calculated detonation velocities (DV) are in the range of
RDX and PETN.
The calculated specific impulses (Is) of the trinitromethyl-
containing compounds are in the range of the maximum value
of aluminised mixtures of AP, and are considerably higher than
those of the fluorodinitromethyl-containing compounds.
The dipotassium 5-(dinitromethylide)-tetrazolate reveals
desirable detonation parameters while being thermally stable
up to 2808C and shows sensitivities in the range of PETN.
The solid-state enthalpies of formation for the ionic compounds
are derived from the calculation of the corresponding lattice
energies (UL) and lattice enthalpies (HL), calculated from the corre-
sponding molecular volumes, by the equations provided by Jen-
kins et al.[57] The derived molar standard enthalpies of formation
for the solid state (DHm) were used to calculate the solid-state en-
ergies of formation (DUm) according to Equation (1), with Dn being
the change in the number of mol of gaseous components.[1]
Experimental Section
General procedures
Melting points (Tm) and decomposition points (Tdec) were measured
with a Perkin–Elmer Pyris6 DSC (Tonset), by using a heating rate of
58Cminꢀ1 and checked by a Bꢃchi Melting Point B-540 apparatus.
Infrared spectra were measured with a Perkin–Elmer Spectrum BX-
&
&
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
8
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
Raman (200 mW): n˜ =3033 (52), 2902 (38), 1683 (10), 1607 (32),
1471 (100), 1362 (43), 1317 (15), 1213 (10), 1190 (50), 1160 (17),
1101 (39), 1068 (20), 984 (53), 949 (60), 838 (70), 803 (10), 651 (8),
530 (7), 444 cmꢀ1 (16); MS (high res., FAB+): m/z: 190.99
[C2N6O4F]+; elemental analysis calcd (%) for C2H4N7O4F: C 11.49, H
1.93, N 46.89; found: C 11.90, H 1.99, N 46.49; drophammer: 1 J;
friction tester: 16 N; ESD: 100 mJ; grain size: <100 mm.
DUm ¼ DHmꢀDnRT
ð1Þ
The calculations affecting the detonation parameters were carried
out by using the program package EXPLO5, V6.02,[47] with CBS-4M-
calculated enthalpies of formation, and densities obtained from
ambient temperature X-ray diffraction measurements. The detona-
tion parameters were calculated at the C–J point (Chapman–Jou-
guet point) with the aid of the steady-state detonation model by
using a modified Becker–Kistiakowski–Wilson equation of state for
modelling the system. The C–J point was found from the Hugoniot
curve of the system by its first derivative.[58] Also the specific
impulses Is were calculated with the EXPLO5, V6.02 program,[47] as-
suming an isobaric combustion, and a chamber pressure of
70.0 bar against an ambient pressure of 1.0 bar with equilibrium
expansion conditions at the nozzle throat.
2-(2-Nitro-2-azapropyl)-5-(trinitromethyl)tetrazole (9): 2-Nitro-2-
azapropyl chloride (3) (130 mg, 1.04 mmol) was added to a solution
of ammonium 5-(trinitromethyl)tetrazolate (3) (250 mg, 1.06 mmol)
in anhydrous acetone (10 mL). The solution was stirred overnight
at ambient temperature. Precipitated ammonium chloride was fil-
tered off and washed with dichloromethane. Water (10 mL) was
added to the filtrate and the mixture was extracted with dichloro-
methane (4ꢂ10 mL). The combined organic phases were dried
over MgSO4 and the solvent was concentrated to 2 mL under re-
duced pressure. Methanol (2 mL) was added to the residue and
the 1:1 mixture was kept at 88C overnight whereas the desired
compound 9 crystallised as colourless crystals (250 mg, 0.81 mmol,
Syntheses
CAUTION! All of the described compounds are energetic materials
with high sensitivities towards heat, impact, friction and electro-
static discharge. Although no incidents occurred during prepara-
tion and manipulation, additional proper protective precautions
like face shield, leather coat, earthed equipment and shoes, Kevlar
gloves and ear plugs should be used when undertaking work with
these compounds.
Ammonium 5-(fluorodinitromethyl)-tetrazolate (3),[18] potassium
dinitroacetonitrile (4)[16,26–28] and 2-nitro-azapropyl chloride (8)[29a]
were synthesised according to the literature-known procedures
and purified by re-crystallisation (compounds 3 and 4) and distilla-
tion (compound 8).
78%). DSC (58Cminꢀ1): Tm =878C,
T
dec =1348C; 1H NMR
([D6]acetone, 399.8 MHz): d=7.00 (s, 2H; CH2), 3.70 ppm (s, 3H;
CH3); 13C NMR ([D6]acetone, 100.5 MHz): d=152.3 (CTz), 121.2
(C(NO2)3), 67.6 (CH2), 38.6 ppm (CH3); 14N NMR ([D6]acetone,
28.9 MHz): d=ꢀ33 (NNO2), ꢀ37 ppm (C(NO2)3); IR: n˜ =3068 (w),
3007 (w), 2883 (w), 1623 (m), 1598 (s), 1540 (s), 1468 (m), 1447 (m),
1420 (m), 1384 (w), 1331 (m), 1299 (s), 1258 (s), 1198 (m), 1132 (m),
1101 (w), 1044 (m), 1010 (s), 987 (m), 961 (w), 943 (m), 857 (w), 843
(s), 821 (w), 798 (s), 760 (s), 734 (m), 690 (m), 654 cmꢀ1 (w); Raman
(300 mW): n˜ =3069 (34), 3038 (34), 3008 (100), 2963 (72), 2890 (20),
2859 (12), 1627 (20), 1608 (26), 1541 (9), 1487 (60), 1422 (18), 1398
(30), 1347 (12), 1305 (21), 1261 (42), 1134 (8), 1046 (27), 989 (29),
962 (30), 946 (40), 859 (86), 845 (61), 803 (7), 770 (10), 691 (8), 656
(10), 604 cmꢀ1 (17); MS (FABꢀ): m/z: 306.4 [MꢀH]ꢀ; elemental analy-
sis calcd (%) for C4H5N9O8: C 15.64, H 1.64, N 41.04; found: C 18.43,
H 2.08, N 25.09; drophammer: 3 J; friction tester: 40 N; ESD:
100 mJ; grain size: 100–500 mm.
Ammonium 5-(fluorodinitromethyl)-tetrazolate (6): Selectfluor
(10.00 g, 28.4 mmol) was added to a yellow solution of potassium
dinitroacetonitrile (4) (3.00 g, 17.7 mmol) in anhydrous acetonitrile
(100 mL) and the mixture was stirred until the reaction mixture
turned colourless (2–3 h). The reaction mixture was distilled (828C)
by means of an additional argon flow and a cooling trap (ꢀ788C)
and fluorodinitroacetonitrile (5) was detected by multinuclear NMR
spectroscopy in the resulting acetonitrile solution. 14N NMR
([D6]acetone, 28.9 MHz): d=ꢀ37 ppm (d, 2J(14N,F)=11 Hz, NO2);
19F NMR ([D6]acetone, 376.5 MHz): d=ꢀ93.3 ppm (q, 2J(F,14N)=
11 Hz, C(NO2)2F).
2-(2-Nitro-2-azapropyl)-5-(fluorodinitromethyl)-tetrazole (10): 2-
Nitro-2-azapropyl chloride (3) (150 mg, 1.20 mmol) was added to
a solution of ammonium 5-(fluorodinitromethyl)-tetrazolate (6)
(250 mg, 1.20 mmol) in anhydrous acetone (10 mL). The solution
was stirred overnight at ambient temperature. Precipitated ammo-
nium chloride was filtered off and washed with dichloromethane.
Water (10 mL) was added to the filtrate and the mixture was ex-
tracted with dichloromethane (4ꢂ10 mL). The combined organic
phases were dried over Na2SO4 and the solvent was concentrated
to 2 mL under reduced pressure. Methanol (2 mL) was added to
the residue and the 1:1 mixture was kept at 88C overnight whereas
the desired compound 10 crystallised as colourless crystals
(260 mg, 0.93 mmol, 78%). DSC (Tonset): Tm =468C, Tdec =1848C;
1H NMR ([D6]acetone, 399.8 MHz): d=6.96 (s, 2H; CH2), 3.69 ppm (s,
Sodium azide (1.48 g, 22.8 mmol or 3 mL trimethylsilyl azide) was
added to the acetonitrile solution containing compound 5. The re-
action mixture was stirred in a barred flask at ambient temperature
overnight and additional 12 h at 508C. The solvent was evaporated
under reduced pressure and the remaining yellow oil was treated
with water for 2 h. The solution was filtered off and the water was
evaporated again under reduced pressure. The resulting brownish
oil was stirred with aqueous ammonia (4 mL, 25%) for 30 min. The
solvent was evaporated and the resulting tan solid was re-crystal-
lised in a 1:1 mixture of ethyl acetate and toluene (10 mL) yielding
ammonium 5-(fluorodinitromethyl)-2H-tetrazolate (6) (1.18 g,
5.7 mmol, two steps yield from compound 4: 32%) as colourless
crystals. DSC (58Cminꢀ1, Tonset): Tdec =1668C; 1H NMR ([D6]acetone,
399.8 MHz): d=8.42 ppm (brs, 4H; NH4); 13C NMR ([D6]acetone,
100.5 MHz): d=150.8 (d, 2J(C,F)=23.0 Hz, CTz), 119.9 ppm (d,
1J(C,F)=284.7 Hz, C(NO2)2F); 15N NMR ([D6]acetone, 40.6 MHz): d=
2
3H; CH3); 13C NMR ([D6]acetone, 100.5 MHz): d=153.7 (d, J(C,F)=
25.4 Hz, CTz), 115.4 (d, J(C,F)=282.9 Hz, C(NO2)2F), 67.3 (CH2),
38.6 ppm (CH3); 14N NMR ([D6]acetone, 28.9 MHz): d=ꢀ27 (d,
2J(N,F)=10 Hz, C(NO2)2F), ꢀ32 ppm (s, NNO2); 19F NMR ([D6]acetone,
376.5 MHz): d=ꢀ99.6 ppm (brs, CF); IR: n˜ =3050 (w), 3005 (w),
2967 (w), 1626 (s), 1595 (m), 1537 (s), 1461 (m), 1427 (w), 1409 (w),
1349 (m), 1325 (w), 1305 (m), 1260 (s), 1164 (m), 1084 (m), 1054
(w), 1039 (s), 963 (s), 871 (w), 835 (s), 804 (s), 765 (s), 722 (s), 684
(s), 664 cmꢀ1 (m); Raman (300 mW): n˜ =3069 (34), 3038 (34), 3008
(100), 2963 (72), 2890 (20), 2859 (12), 1627 (20), 1608 (26), 1541 (9),
1487 (60), 1422 (18), 1398 (30), 1347 (12), 1305 (21), 1261 (42), 1134
(8), 1046 (27), 989 (29), 962 (30), 946 (40), 859 (86), 845 (61), 803
(7), 770 (10), 691 (8), 656 (10), 604 cmꢀ1 (17); MS (FABꢀ): m/z: 306.4
2
9.6 (Na), ꢀ20.6 (d, J15(N,F)=16.5 Hz, NO2), ꢀ57.5 (Nb), ꢀ362.2 ppm
(NH4+); 19F NMR ([D6]acetone, 376.5 MHz) d=ꢀ95.5 ppm (brs, CF);
IR: n˜ =3192 (m), 3026 (m), 2873 (m), 2806 (m), 1924 (vw), 1685
(vw), 1605 (vs), 1595 (vs), 1457 (vs), 1424 (s), 1408 (m), 1361 (w),
1310 (m), 1238 (s), 1190 (s), 1160 (w), 1152 (w), 1099 (s), 1066 (vw),
1046 (w), 982 (vs), 947 (w), 836 (vs), 798 (vs), 740 (w), 704 cmꢀ1 (w);
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
9
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
[MꢀH]ꢀ; elemental analysis calcd (%) for C4H5N8O6F: C 17.15, H
1.80, N 40.00; found: C 18.43, H 2.08, N 25.09; drophammer: 2 J;
friction tester: 36 N; ESD: 100 mJ; grain size: 100–500 mm.
[5] M. Gçbel, K. Karaghiosoff, T. M. Klapçtke, D. G. Piercey, J. Stierstorfer, J.
Am. Chem. Soc. 2010, 132, 17216–17226.
[6] T. M. Klapçtke, D. G. Piercey, J. Stierstorfer, Propellants Explos. Pyrotech.
2011, 36, 160–167.
Dipotassium 5-(dinitromethylide)-tetrazolate (11): A solution of
compound 3 (0.5 g, 2.12 mmol) in water (20 mL) was acidified with
HCl until pH 2 was reached and the solution was extracted with di-
chloromethane (4ꢂ40 mL). The organic phases were dried over
Na2SO4 and the solvent was evaporated under reduced pressure.
The residue was treated with an aqueous solution of KOH (10m)
overnight, the solvent was evaporated under reduced pressure
and the residue was re-crystallised in a 1:1 mixture of ethyl acetate
and toluene (20 mL) yielding the dipotassium salt 11 (410 mg,
1.64 mmol, 77%) as colourless crystals. DSC (Tonset): Tm =2848C,
[7] a) H. Gao, R. Wang, B. Twamley, M. A. Hiskey, J. M. Shreeve, Chem.
Commun. 2006, 4007–4009; b) T. M. Klapçtke, A. Preimesser, J. Stierstor-
fer, Z. Naturforsch. B 2013, 68, 1310–1320; c) T. M. Klapçtke, A. Prei-
messer, S. Schedlbauer, J. Stierstorfer, Cent. Eur. J. Energ. Mater. 2013,
10, 151–170.
[8] B. Das, C. R. Reddy, D. N. Kumar, M. Krishnaiah, R. Narender, Synlett
2010, 391–394.
[9] T. M. Klapçtke, C. M. Sabatꢄ, J. Stierstorfer, New J. Chem. 2009, 33, 136–
147.
[10] T. M. Klapçtke, J. Stierstorfer, Helv. Chim. Acta 2007, 90, 2132–2150.
[11] a) T. M. Klapçtke, S. M. Sproll, J. Polym. Sci. Part A 2010, 48, 122–127;
b) T. M. Klapçtke, S. M. Sproll, Eur. J. Org. Chem. 2010, 1169–1175;
c) F. M. Betzler, R. Boller, A. Grossmann, T. M. Klapçtke, Z. Naturforsch. B
2013, 68, 714–718; d) F. M. Betzler, T. M. Klapçtke, S. M. Sproll, Eur. J.
Org. Chem. 2013, 509–514.
T
dec =2918C; 13C NMR ([D6]acetone, 100.5 MHz): d=155.2 (CTz),
128.5 ppm (C(NO2)2); 14N NMR ([D6]acetone, 28.9 MHz) d=
ꢀ23 ppm (NO2); drophammer: 4 J; friction tester: 160 N; ESD:
100 mJ; grain size: 100–500 mm.
[12] a) M.-J. Crawford, T. M. Klapoetke, H. Radies, J. Fluorine Chem. 2008, 129,
1199–1205; b) E.-C. Koch, A. Hahma, T. M. Klapoetke, H. Radies, Propel-
lants Explos. Pyrotech. 2010, 35, 248–253; c) E.-C. Koch, T. M. Klapotke,
H. Radies, K. Lux, A. Hahma, Z. Naturforschung 2011, 66, 378–386.
[13] a) Q. J. Axthammer, M. A. Kettner, T. M. Klapçtke, R. Moll, S. F. Rest, Pro-
ceedings of Seminar on New Trends in Research of Energetic Materials,
NTREM, Proceedings of the 16th Seminar, Pardubice (Czech Republic),
April 10th–12th, 2013, Part 1, 29–39; b) Q. J. Axthammer, M. A. Kettner,
T. M. Klapçtke, R. Moll, S. F. Rest, Development of High Energy Dense
Oxidizers based on CHNO(F)-Materials, EUCASS Conference, Munich
(Germany), July 3rd, 2013; c) M. A. Kettner, T. M. Klapçtke, Synthesis of
New Oxidizers for Potential Use in Solid Rocket Propellants, New Ener-
getic Materials and Propulsion Techniques for Space Exploration, Milano
(Italy), June 9th–10th 2014.
[14] M. Gçbel, T. M. Klapçtke, Adv. Funct. Mater. 2009, 19, 347–365.
[15] V. Grakauskas, A. H. Albert, J. Heterocycl. Chem. 1981, 18, 1477–1479.
[16] A. V. Fokin, Y. N. Studnev, A. I. Rapkin, V. A. Komarov, O. V. Verenikin,
T. M. Potarina, Izv. Akad. Nauk SSSR, Ser. Khim. 1981, 7, 1592–1595.
[17] R. A. Wiesboeck, J. R. Ruff, J. Org. Chem. 1968, 33, 1257–1258.
[18] K. O. Christe, R. Haiges, Inorg. Chem. 2013, 52, 7249–7260.
[19] a) E. D. McLanahan, J. L. Campbell, D. C. Ferguson, B. Harmon, J. M.
Hedge, K. M. Crofton, D. R. Mattie, L. Braverman, D. A. Keys, M. Mumtaz,
J. W. Fisher, Toxicol. Sci. 2007, 97, 308–317; b) R. E. Tarone, L. Lipworth,
J. K. McLaughlin, Occup. Environ. Med. 2010, 52, 653; c) A. K. Mandal,
G. M. Kunjir, J. Singh, S. S. Adhav, S. K. Singh, R. K. Pandey, B. Bhattachar-
ya, M. L. Kantam, Cent. Eur. J. Energ. Mater. 2014, 11, 83–97.
[20] J. Dumont, SERDP Project ER-1236, 2008.
Acknowledgements
Financial support of this work by the Ludwig-Maximilian Uni-
versity of Munich (LMU), the U.S. Army Research Laboratory
(ARL) under grant no. W911NF-09-2-0018, the Armament Re-
search, Development and Engineering Center (ARDEC) under
grant nos. W911NF-12-1-0467 and W911NF-12-1-0468 and the
Office of Naval Research (ONR) under grant nos. ONR.N00014-
10-1-0535 and ONR.N00014-12-1-0538 is gratefully acknowl-
edged. The authors acknowledge collaborations with Dr. Mila
Krupka (OZM Research, Czech Republic) in the development of
new testing and evaluation methods 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 Dr. Betsy M. Rice and Dr. Brad Forch
(ARL, Aberdeen, Proving Ground, MD) for many inspired dis-
cussions. M.Sc. Swetlana Wunder and M.Sc. Johannes Feierfeil
are acknowledged for their participation in this project as part
of their practical course. Dr. Burkhard Krumm and Dr. Jçrg
Stierstorfer are thanked for safety advice. The X-ray team
around Prof. Dr. Konstantin Karaghiosoff is gratefully thanked
for various measurements.
[21] B. Sellers, K. Weeks, W. R. Alsop, Perchlorate Environmental Problems and
Solutions, CRC, Boca Raton, FL (USA), 2007.
[22] G. da Silva, S. C. Rufino, K. Iha, J. Aerosp. Technol. Manag. 2013, 5, 139–
144.
[23] N. Fischer, K. Karaghiosoff, T. M. Klapçtke, J. Stierstorfer, Z. Anorg. Allg.
Chem. 2010, 636, 735–749.
[24] L. I. Vereshchagin, O. N. Verkhozina, F. A. Pokatilov, S. K. Strunevich, A. G.
Proidakov, V. N. Kizhnyaev, Russ. J. Org. Chem. 2007, 43, 1710–1714.
[25] D. W. Hutchinson, M. Naylor, Nucleic Acids Res. 1985, 13, 8519–8530.
[26] M. Conrad, A. Schulze, Ber. Dtsch. Chem. Ges. 1909, 42, 735–742.
[27] C. O. Parker, Tetrahedron 1962, 17, 109–116.
Keywords: energetic oxidisers
elucidation · tetrazoles · thermal analysis
·
nitramines
·
structure
[1] a) T. M. Klapçtke, Chemie der Hochenergetischen Materialien, de Gruyter,
Berlin, 2009; b) T. M. Klapçtke, Chemistry of High-Energy Materials, de
Gruyter, Berlin, 2011.
[28] C. O. Parker, U. S. Patent 3415867, 1968.
[29] a) J. Majer, J. Denkstein, Collect. Czech. Chem. Commun. 1966, 31, 2547–
´
2557; b) B. Aas, M. A. Kettner, T. M. Klapçtke, M. Suceska, C. Zoller, Eur. J.
Inorg. Chem. 2013, 6028–6036.
[2] a) T. M. Klapçtke, D. G. Piercey, Inorg. Chem. 2011, 50, 2732–2734;
b) T. M. Klapçtke, N. Fischer, D. Fischer, D. Piercey, J. Stierstorfer, M. Rey-
mann, Pat. WO 026768A1, 2013.
[30] C. H. Lim, S. Hong, K.-H. Chung, J. S. Kim, J. R. Cho, Bull. Korean Chem.
Soc. 2008, 29, 1415–1417.
[31] H.-O. Kalinowski, S. Berger, S. Braun, 13C NMR-Spektroskopie, Thieme,
Stuttgart, 1984.
[32] M. Witanowski, L. Stefaniak, G. A. Webb, Annual Reports on NMR Spec-
troscopy, Vol. 25, Academic Press Inc., London, 1993.
[33] G. Socrates, Infrared and Raman Characteristic Group Frequencies: Tables
and Charts, 3rd ed., Wiley, New York, 2004.
[34] A. F. Holleman, E. Wiberg, Lehrbuch der Anorganischen Chemie, 101st ed.,
de Gruyter, Berlin, 1995, p. 1842.
[3] a) A. Dippold, T. M. Klapçtke, F. A. Martin, Z. Anorg. Allg. Chem. 2011,
´
637, 1181–1193; b) T. M. Klapçtke, Thomas, C. Pflꢃger, M. Suceska, New
Trends in Research of Energetic Materials, NTREM, Proceedings of the
17th Seminar, Pardubice (Czech Republic), April 9th–11th, 2014, 2,
754–768.
[4] a) R. Wang, Y. Guo, Z. Zheng, B. Twamley, J. M. Shreeve, Chem. Eur. J.
2009, 15, 2625–2634; b) M. A. Hiskey, D. E. Chavez, R. L. Bishop, J. F.
Kramer, S. A. Kinkead, U. S. Patent 6358339, Assignee: The Regents of
the University of California, Los Alamos, NM (USA), 2002.
&
&
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
10
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
[35] Y. Oyumi, T. B. Brill, A. L. Rheingold, J. Phys. Chem. 1985, 89, 4824–4828.
[36] A. Bondi, J. Phys. Chem. 1964, 68, 441–451.
[37] a) M. A. Kettner, T. M. Klapçtke, Chem. Commun. 2014, 50, 2268–2270;
mann, 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. Dan-
nenberg, S. Dapprich, A. D. Daniels, ꢈ. Farkas, J. B. Foresman, J. V. Ortiz,
J. Cioslowski, D. J. Fox, Gaussian, Inc., Wallingford, CT, 2009; b) Gauss-
View 5, V5.0.8, T. K. R. Dennington, J. Millam, Semichem Inc., Shawnee
Mission, 2009.
´
b) M. A. Kettner, K. Karaghiosoff, T. M. Klapçtke, M. Suceska, S. Wunder,
Chem. Eur. J. 2014, 20, 7622–7631.
[38] T. M. Klapçtke, B. Krumm, S. F. Rest, M. Reynders, R. Scharf, Eur. J. Inorg.
Chem. 2013, 5871–5878.
[39] T. M. Klapçtke, F. X. Steemann, Propellants Explos. Pyrotech. 2010, 35,
114–129.
[46] a) J. J. A. Montgomery, M. J. Frisch, J. W. Ochterski, G. A. Petersson, J.
Chem. Phys. 2000, 112, 6532–6542; b) J. W. Ochterski, G. A. Petersson,
J. J. A. Montgomery, J. Chem. Phys. 1996, 104, 2598–2619.
´ ´
[47] a) M. Suceska, Version 6.02, Zagreb (Croatia), 2014; b) M. Suceska, Pro-
[40] a) Bundesanstalt fꢃr Materialforschung (BAM), http://www.bam.de;
laying down the test methods pursuant to Regulation (EC) No. 1907/
2006 of the European Parliament and of the Council on the Evaluation,
Authorisation and Restriction of Chemicals (REACH), ABl. L 142, 2008;
b) NATO Standardisation Agreement (STANAG) on Explosives, Impact
Tests, No. 4489, 1st ed., September 17th, 1999; c) WIWEB-Standardar-
beitsanweisung 4–5.1.02, Ermittlung der Explosionsgefꢅhrlichkeit, hier:
der Schlagempfindlichkeit mit dem Fallhammer, November 8th, 2002;
d) NATO Standardisation Agreement (STANAG) on Explosives, Friction
Tests, No. 4487, 1st ed., August 22nd, 2002; e) WIWEB-Standardarbeit-
sanweisung 4–5.1.03, Ermittlung der Explosionsgefꢅhrlichkeit, hier: der
Reibempfindlichkeit mit dem Reibeapparat, November 8th, 2002;
f) T. M. Klapçtke, B. Krumm, N. Mayr, F. X. Steemann, G. Steinhauser,
Safety Science 2010, 48, 28–34.
[41] a) Test methods according to the UN Manual of Tests and Criteria, Rec-
ommendations on the Transport of Dangerous Goods, United Nations
Publication, New York, Geneva, 4th revised ed., 2003: Impact: insensi-
tive >40 J, less sensitive ꢃ35 J, sensitive ꢃ4 J, very sensitive ꢁ3 J; fric-
tion: insensitive >360 N, less sensitive 360 N, sensitive <360 N and
>80 N, very sensitive ꢁ80 N and extremely sensitive ꢁ10 N; b) http://
www.reichel-partner.de.
[42] a) NATO Standardisation Agreement (STANAG) on Explosives, Electro-
static Discharge Sensitivity Tests, No. 4490, 1st ed., February 19th, 2001;
b) S. Zeman, V. Pelikꢆn, J. Majzlꢇk, Cent. Eur. J. Energ. Mater. 2006, 3, 45–
51; c) D. Skinner, D. Olson, A. Block-Bolten, Propellants Explos. Pyrotech.
1998, 23, 34–42.
[43] http://www.ozm.cz/en/sensitivity-tests/esd-2008a-small-scale-electrosta-
ticspark-sensitivity-test/.
[44] A. Penger, Dissertation: Offenkettige Nitramine als potentielle Ersatz-
stoffe fꢃr Cyclotrimethylentrinitramin (RDX), LMU Munich (Germany),
2011.
´
pellants Explos. Pyrotech. 1991, 16, 197–202; c) M. Suceska, Propellants
Explos. Pyrotech. 1999, 24, 280–285; d) M. Suceska, H. G. Ang, H. Y.
Chan, Mater. Sci. Forum 2011, 673, 47–52.
[48] a) NASA, Space Shuttle News Reference, 2-20-22-21, http://de.scribd.-
com/doc/17005716/NASA-Space-Shuttle-News-Reference-1981;
b) NASA, press release: STS-122 The Voyage of Columbus, 2008, 82–84.
[49] P. W. Cooper, Explosives Engineering, 1st ed., Wiley-VCH, Weinheim,
1996.
[50] a) CrysAlisPro, Version 1.171.35.11 (release 16.05.2011 CrysAlis171.net),
Agilent Technologies, 2011; b) L. J. Farrugia, J. Appl. Crystallogr. 1999,
32, 837–838.
[51] M. C. Burla, R. Caliandro, M. Camalli, B. Carrozzini, G. L. Cascarano, L.
De Caro, C. Giacovazzo, G. Polidoria, R. Spagna, J. Appl. Crystallogr.
2005, 38, 381–388.
[52] a) SHELX-97, G. M. Sheldrick, University of Gçttingen, Gçttingen (Germa-
ny), 1997; b) G. M. Sheldrick, Acta Crystallogr. Sect. A 2008, 64, 112–122;
c) A. L. Spek, Acta Crystallogr. Sect. D 2009, 65, 148–155.
[53] DIAMOND–Infomationssystem fꢃr Kristallstrukturen, K. Brandenburg,
Universitꢅt Bonn, Bonn, (Germany), 1996.
[54] T. M. Klapçtke, J. Stierstorfer, Phys. Chem. Chem. Phys. 2008, 10, 4340–
4346.
[55] a) E. F. C. Byrd, B. M. Rice, J. Chem. Phys. A 2006, 110, 1005–1013;
b) L. A. Curtiss, K. Raghavachari, P. C. Redfern, J. A. Pople, J. Chem. Phys.
1997, 106, 1063–1079.
[56] a) F. Trouton, Philos. Mag. 1884, 18, 54–57; b) P. Atkins, Physical Chemis-
try, Oxford University Press, Oxford, 1978.
[57] 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.
[58] a) T. M. Klapçtke, B. Krumm, F. X. Steemann, K. D. Umland, Z. Anorg. Allg.
´
[45] a) Gaussian 09, Revision C.01, 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. Hratch-
ian, 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. 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. Strat-
Chem. 2010, 636, 2343–2346; b) M. Suceska, Propellants Explos. Pyro-
tech. 1991, 16, 197–202.
´
[59] J. Feierfeil, M. A. Kettner, T. M. Klapçtke, M. Suceska, S. Wunder, New
Trends in Research of Energetic Materials, NTREM, Proceedings of the
17th Seminar, Pardubice (Czech Republic), April 9th–11th, 2014, 2,
738–743.
Received: October 15, 2014
Published online on && &&, 0000
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
11
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
FULL PAPER
Rocket man: Polynitromethyl-contain-
ing compounds represent oxygen-rich
energetic materials as possible oxidisers
for solid rocket propellants. This work
details the alkylation of two polynitro-
methyl tetrazole derivatives by a secon-
dary nitramine moiety and compares
the energetic behaviour of the products
to the starting materials. The crystal
structures of the materials were also
investigated (see figure).
&
Energetic Materials
M. A. Kettner, T. M. Klapçtke*
&& – &&
New Energetic Polynitrotetrazoles
&
&
Chem. Eur. J. 2015, 21, 1 – 12
www.chemeurj.org
12
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!