Tris(triazolo)benzene and its derivatives: High-density energetic materials

Article abstract of DOI:10.1002/anie.201205134

High-performance explosives: Tris(triazolo)benzene was synthesized and converted to its trinitro and trichloro derivatives (see scheme; R=NO ₂, Cl). The heats of formation of this "high-nitrogen" compounds were calculated and combined with experimentally determined densities to determine detonation pressures and velocities. They exhibit high density, good thermal stability, high heats of formation, and moderate to good detonation properties. Copyright

Full text of DOI:10.1002/anie.201205134

Angewandte
Chemie
DOI: 10.1002/anie.201205134
Energetic Materials
Tris(triazolo)benzene and Its Derivatives: High-Density Energetic
Materials**
Venugopal Thottempudi, Farhad Forohor, Damon A. Parrish, and Jeanꢀne M. Shreeve*
The synthesis and development of new energetic materials
continues to focus on new heterocyclic compounds with high
densities, high heats of formation and good detonation
properties. Also, in the preparation of energetic compounds,
higher performance and lower sensitivity continue to be keen
concerns.[1] The need for high energetic materials continues to
expand, of particular interest are nitrogen-rich compounds
(e.g., azoles) in combination with energetic substituents such
as nitro (NO2), nitrato (ONO2), and nitramine (NHNO2)
functionalities, since these compounds have satisfactory
oxygen content.[2] However, the requirements of insensitivity
and high energy with concomitant positive oxygen balance
are often contradictory to each other, making the develop-
ment of new high energy density materials an interesting and
challenging problem.[3]
deleterious impacts on the human thyroid and being a persis-
tent contaminant in ground water.[7]
One recent focus in energetic materials research is the
synthesis of fused cyclic nitrogen-containing heterocycles.
Fused aza-cyclic compounds with ring strain energy could be
used as high performance explosives when nitro and other
energetic groups are present in the ring. Also, fused cyclic
compounds exhibit good thermochemical and physical prop-
erties. Nitrogen aromatic heterocycles are insensitive ener-
getic materials. The functionalization of fused heterocycles is
more difficult than expected.[8] High-nitrogen molecules play
an important role in the design of new energetic compounds
and their use as propellants, explosives and pyrotechnics.
Among nitrogen heterocycles, the triazole ring is the one of
the promising heterocyclic cores for the preparation of high-
energetic materials. Triazole derivatives generally exhibit
desired properties such as positive heat of formation, high
density, and high nitrogen content together with low sensi-
tivity towards external forces. Various heterocyclic systems
have been studied in our group with growing interest.[9]
Hypergolic fuel-oxidizer systems are important in rocket
propellants. Hypergolicity is the spontaneous reaction of one
chemical (fuel) when contacted with another (oxidizer).[10]
These self-ignition systems are of special importance in rocket
propellants, since such fuel-oxidizer combinations simplify
engine design and provide a convenient way of achieving
repeated on-and-off capability at no extra cost. The fuel-
oxidizers hypergolic systems have been widely used in
biliquid propellants. In propellant systems, the fuels of
choice continue to be hydrazine and its derivatives and
common oxidizers include HNO3, N2O4, and H2O2. These
hypergolic combinations require that a successful fuel has
a high energy density per unit mass and a high specific
impulse, and that there is a short ignition delay time.
Unfortunately these oxidizing agents are extremely corrosive
and moisture sensitive and long-time storage is problematic.
Recently, there have been considerable developments in
preparing hypergolic fuels, but not much change with
oxidizers. Therefore, there is an urgent need for an alternative
noncorrosive, hydrolytically stable hypergolic oxidizer, with
high energy densities and short ignition delays.[11]
High-energy materials containing large numbers of nitro-
gen atoms, so called “high-nitrogen” compounds, have been
shown to derive energy from the presence of many energetic
[4]
À
À
N N and C N bonds. High energetic compounds which
have polynitro groups are one of the important classes of
useful energetic materials. Traditional polynitro compounds
produce energy primarily from the combustion of the carbon
backbone, while consuming the oxygen provided by the nitro
groups.[5] The presence of nitro groups tends to decrease the
heat of formation, but contributes markedly to the overall
energetic performance. Also, the nitro group enhances the
oxygen balance and density, which improves the detonation
performances (pressure and velocity).[6] Ammonium perchlo-
rate (AP) is the main oxidizer used in solid rocket fuels.
Oxidizers provide the oxygen needed for oxidation of the fuel
to provide the necessary thrust. The search for a smokeless
propellant has encouraged scientists to look for chlorine-free
oxidizers as a substitute for AP because it contributes to acid
rain and ozone layer depletion, in addition to having
[*] Dr. V. Thottempudi, Prof. Dr. J. M. Shreeve
Department of Chemistry, University of Idaho
Moscow, ID 83844-2343 (USA)
E-mail: jshreeve@uidaho.edu
Dr. F. Forohor
In a continuing effort to seek more powerful, less
sensitive, eco-friendly energetic materials, we are interested
in fused heterocyclic compounds that contain a high percent-
age of both nitrogen and oxygen. Tris(triazolo)benzene could
be such a type of molecule with three triazole units fused into
one benzene ring; a ring system having the advantage of being
rich in nitrogen, as well as having high thermal tolerance.[12] In
1959, Muzik, et al. described the tris(alkyltriazolo)benzene
ring system[13] and in 1993, Samsonov, et al. reported the
Naval Surface Warfare Center
Indian Head, MD 20640-5102 (USA)
Dr. D. A. Parrish
Naval Research Laboratory, Code 6030
Washington DC 20375-5001 (USA)
[**] This work was supported by the Office of Naval Research (N00014-
10-1-0097 to V.T. and J.M.S.; N00014-11-AF-0-0002 to D.A.P.).
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/anie.201205134.
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synthesis of unsubstituted tris(triazolo)benzene starting from
1,3,5-triaminobenzene trihydrochloride.[14] However, in the
recent literature, to the best of our knowledge there is no
report related to the synthesis of tris(triazolo)benzene, none
of its N-functionalized derivatives are known, and their utility
as possible high-nitrogen energetic materials has not been
explored. Herein, we report an improved synthesis of tris-
(triazolo)benzene and its derivatives from easily available
starting materials, and their complete characterization as
nitrogen-rich energetic materials.
Since 1,3,5-triaminobenzene trihydrochloride is an expen-
sive chemical, a short and high-yielding practical synthesis of
triaminobenzene trihydrochloride using various starting
materials was tried. The reaction of 3,5-dinitrobenzoic acid
(1) with sodium azide under strongly acidic conditions
produced a high yield (94%) of 3,5-dinitroaniline (2). In
this reaction, chloroform was a more useful solvent than
dichloromethane. Pure 3,5-dinitroaniline was isolated and
was hydrogenated in THF in the presence of 10% Pd/C under
an hydrogen atmosphere (5 atm), to produce 1,3,5-triamino-
benzene (3) (Scheme 1).[15]
Scheme 2. Synthesis of tris(triazolo)benzene from 3.
(triazolo)benzene was prepared by treating the sodium (9) or
potassium (10) salt with silver nitrate. Treatment of tris-
(triazolo)benzene with aqueous ammonia produced a mixture
of compounds which were difficult to separate (Scheme 3).
Trisubstituted derivatives of tris(triazolo)benzene such as
trinitrotris(triazolo)benzene (13) could be interesting ener-
getic materials. Nitration of 8 using 100% HNO3 did not
produce the product with the starting material being recov-
Scheme 1. Synthesis of1,3,5-triaminobenzene.
With pure 1,3,5-triaminobenzene in hand rather than
making the trihydrochloride salt and subsequently neutraliz-
ing using pyridine before adding to diazotized aniline,[13] we
directly added 3 to the diazotized aniline derivatives, resulting
in a good yield of diazotized product. Among anilines, p-
nitroaniline produced the best results in the diazo-coupling
reactions. p-Nitroaniline (4) was diazotized using NaNO2 in
conc. HCl added at ice cold temperature to produce the
diazo-coupled product (5). Diazo compound 5 was cyclized
using copper sulfate and pyridine to produce 2,5,8-tris(4-
nitrophenyl)-tris(triazolo)benzene (6). Our attempts to
deprotect the p-nitrophenyl group using sodium alkoxides
failed. However, the N-2,4-dinitrophenyl group in azoles
could be easily deprotected using sodium alkoxides. There-
fore, the p-nitrophenyl derivative was nitrated to the corre-
sponding dinitrophenyl compound using mixed acids nitra-
tion, to produce the best yield (76%) at 458C. Treatment of
2,4-dinitrophenyl derivative 7 with sodium in methanol,
followed by acidification produced tris(triazolo)benzene
(8).[14] With three equvialents of sodium in methanol, the
product was obtained in low yield; while with excess
(10 equiv) of sodium, 8 was produced in good yield (86%)
(Scheme 2).
Trianionic metal salts of tris(triazolo)benzene have not
been reported in the literature. When tris(triazolo)benzene
was reacted with sodium hydroxide, trisodium salt 9 resulted.
Similarly, the potassium salt 10 was obtained when 8 was
reacted with potassium hydroxide. Silver salt (11) of tris-
Scheme 3. Metal salts of tris(triazolo)benzene.
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ered. Nitration in mixed acids (HNO3 and H2SO4) produced
an unknown mixture of compounds. Finally, the nitration of
tris(triazolo)benzene was successful in acetic anhydride and
conc. HNO3 to produce the pure trinitro derivative, 13.
Compound 13 is stable when stored in a refrigerator, but
when stored at room temperature, after few days, the product
decomposes producing an acidic smell. Since chlorobenzo-
triazole has many interesting properties, the trichloro deriv-
ative of 8 could be a very interesting molecule, and could have
oxidation properties superior to N-chlorobenzotriazole.
Tris(triazolo)benzene was treated with sodium hypochlor-
ite solution in acetic acid to give the pure trichloro derivative
(14) (80%). When the potassium salt of tris(triazolo)benzene
was treated with oxone, the trihydroxy derivative (15) was not
produced (Scheme 4).
N1/N3 and N2 peaks appeared at a close range around
70 ppm. Surprisingly in the case of metal salts 9 and 10, the N1
and N3 nitrogen peaks appeared as a single peak upfield from
N2 nitrogen.
To obtain a better understanding of N-substitution on the
tris(triazolo)benzene, attempts to crystallize trinitro com-
pound 13 in acetone/water at room temperature led to single
crystals of bis(2-N-nitrotriazolo)triazolobenzene (16) suitable
for X-ray structuring resulting from the decomposition of 13
(Figure 1). Compound 16 crystallizes in the monoclinic space
Figure 1. Single-crystal X-ray structures of 16·2H2O.
group P21/c with four molecules in the unit cell. The triazole
rings of 16·2H2O are nearly planar and bond lengths are
Scheme 4. N-Functionalization of tris(triazolo)benzene.
À
found to be similar to those observed in benzotriazoles [N1
À
À
The structures of the tris(triazolo)benzene and its deriv-
atives are supported by IR, 1H, 13C NMR and, in some cases,
15N NMR spectroscopic data as well as elemental analysis (or
high-resolution mass spectrometry, HRMS). The 13C NMR
spectra of 8 showed only a single peak at 132 ppm in
[D6]DMSO (dimethylsulfoxide), which suggests that the
hydrogen is shifting from the N1 to the N3 nitrogen atom of
the triazole rings of tris(triazolo)benzene. All the salts of 8
showed two 13C peaks which shows that the negative charge is
on the N1 nitrogen. In the substituted triazoles 13 and 14 all
the carbon atoms are equivalent; in the 13C NMR spectrum
only one carbon peak was observed, which indicates that
substitution occurred on the middle nitrogen atom. The
resonance bands appeared at 136 and 134 ppm, respectively.
In case of metal salts 9 and 10 two 13C peaks were observed,
which confirms that the negative charge is on the nitrogen
(N1) adjacent to the carbon (Scheme 3).
N2 1.336(16) ꢀ, N3 N4 1.369(19) ꢀ, N4 C5 1.326(16) ꢀ,
[16]
À
À
À
N1 C5 1.349(18) ꢀ].
The C C bond lengths [C13 C9
1.392(7) ꢀ] of the unsubstituted triazole ring are in the range
observed for benzotriazoles whereas nitro-substituted tria-
À
À
À
zole C C bonds [C3 C14 1.419(6) ꢀ, C4 C8 1.425(6) ꢀ] are
slightly longer. The nitro group lies in the plane of the triazole
ring where the oxygen atoms are twisted slightly out of plane
(Figure 1). The packing structure of 16·2H2O is strongly
influenced by strong hydrogen bonds between H2O and 16.
There is extensive hydrogen bonding interactions between
oxygen atom O1S from water and N11 (See Supporting
Information).
The chlorine in N-chlorobenzotriazole is positive as is
shown by its behavior as an oxidizing reagent in converting
a variety of alcohols to aldehydes.[17] By analogy, trichlorotris-
(triazolo)benzene (14) should have very good oxidation
properties with alcohols. We examined the oxidation of
benzyl alcohol, cyclohexanol and 2-propanol to the corre-
sponding aldehydes, that is, benzaldehyde (85%), cyclohex-
anone (71%), and acetone (69%), respectively, within
15 min. Similar to chlorobenzotriazoles, trichlorotris-
(triazolo)benzene could be used as a powerful chlorinating
15N NMR spectra of 7, 8, 10 and 13 are discussed here. In
tris(triazolo)benzene (8) the N1/N3 signal appeared as
a single peak at 81 ppm whereas N2 appeared at 30 ppm.
For the 2,4- dinitrophenyl derivative (7), N2 appeared upfield
to N1/N3 nitrogen. In case of the trinitro derivative 13, the
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agent. Chloramines are used as disinfectants and antisep-
standard BAM Fallhammer techniques.[19] For all of the
compounds, the impact sensitivities range from those of the
relatively less sensitive 7 (19.0 J) and 8 (18.0 J) to the very
sensitive compound 13 (3.0 J). Thermal stabilities of the
energetic compounds were determined with differential
scanning calorimetry (DSC) at a scan rate of 58CminÀ1.
tics;[17c] chlorotris(triazolo)benzene with three N Cl bonds
À
may be a very strong disinfectant and useful in water
purification.
While trichlorotris(triazolo)benzene (14) has poor solu-
bility in common organic solvents, it is more soluble in N,N-
dimethylformamide. Surprisingly trichlorotris(triazolo)-
benzene (14) was found to be hypergolic when a drop of
dimethylsulfoxide was added to the solid. Trichlorotris-
(triazolo)benzene (14) was also hypergolic with aniline,
diethylenetriamine, and hydroxyethylethylenediamine, as
well as with the commonly used fuels, hydrazine hydrate
and monomethylhydrazine. To observe and measure actual
ignition delay, a droplets test was selected because it is
flexible, accurate, simply carried out, and very useful for
screening materials and assessing their potential for hyper-
golic activity. A small amount of a fuel (hydrazine hydrate or
monomethylhydrazine) sample (10–50 mL) was dropped into
a glass vial containing an excess of 14. A high-speed camera
recording 500 frames per second was used to record the time
duration from the moment the fuel contacted the surface of
the oxidizer until the first sign of a visible flame—the ignition
delay time. Chemical delay measurements show that 14 is
a good hypergolic oxidizer with shorter ignition delay times
with hydrazine hydrate (8 ms) and methylhydrazine (1 ms)
compared to white fuming nitric acid (WFNA) (19 ms with
hydrazine hydrate and 20 ms with methylhydrazine).[18] Com-
pound 14 is hydrolytically stable and might be considered as
an alternative to traditional oxidizer WFNA in rocket
propellent systems.
Compound
7
decomposed at 4008C, whereas tris-
(triazolo)benzene (8) decomposed at 3528C. Sequential
decomposition was observed for the trinitro derivative 13;
decomposition was initiated at 388C, with the second
decomposition at 1618C and finally the tris(triazolo)benzene
core decomposed at 3568C. The trichloro derivative 14
decomposed at 2078C. Metal salts 9, 10, and 11 decomposed
at 162, 283, and 3918C, respectively.
By using the calculated values of the heats of formation
and the experimental values for the densities (gas pycno-
meter, 258C) of the new tris(triazolo)benzene derivatives, the
detonation pressures (P) and detonation velocities (D) were
calculated based on traditional Chapman–Jouget thermody-
namic detonation theory using Explo 5.05 (Table 1).[20] The
detonation pressures of tris(triazolo)benzene and its deriva-
tives lie in the range P = 19.41 to 31.2 GPa (compared with
TNT 19.53 GPa and PETN 31.39 GPa). Detonation velocities
lie between D = 6234 and 8376 msÀ1 (compared with TNT
6881 msÀ1 and PETN 8564 msÀ1). The calculated properties
coupled with the rather high thermal and hydrolytic stabilities
suggest that these high-nitrogen materials may be attractive
candidates for energetic applications.
In summary, tris(triazolo)benzene (8) was synthesized by
using straightforward methods. Metal salts (9, 10 and 11) and
N-substituted nitro (13) and chloro (14) derivatives of 8 were
synthesized in high yields. Their physical and detonation
properties were determined. These tris(triazolo)benzene
compounds were fully characterized by using IR and multi-
As shown in Table 1, the tris(triazolo)benzene and its
derivatives exhibit energetic properties. Tris(triazolo)benzene
derivatives 7, 8, 13, and 14 exhibit positive heats of formation
that are superior to those of trinitrotoluol (TNT) and
pentaerythritol tetranitrate (PETN). The densities of these
compounds are in the range of 1.69–1.94 gcmÀ3 which equals
or exceeds that of common explosives. For sodium, potassium,
and silver salts 9, 10 and 11, densities are in the range of 2.1–
2.8 gcmÀ3. Impact sensitivity measurements were made using
1
nuclear H, and 13C NMR (some cases 15N NMR) spectros-
copy, and elemental analysis (or HRMS). A single-crystal X-
ray structure of dinitrotris(triazolo)benzene (16) was
obtained. Trichloro derivative 14 oxidized alcohols to alde-
hydes thus demonstrating some interesting properties. Also,
14 was found to be a powerful hypergolic oxidizer with
various commonly used fuels resulting in better ignition delay
times then those compared to WFNA. These tris-
(triazolo)benzene compounds exhibit good physical and
detonation properties, such as high thermal stabilities, high
densities, high heats of formation, and moderate to good high
detonation pressures and velocities. Calculated detonation
values for these compounds are comparable to those of
explosives such as TNT and PETN, which suggests that they
might be of interest for future applications as environmentally
friendly and high-performing nitrogen materials.
Table 1: Physical properties of tris(triazolo)benzene derivatives com-
pared with TNT and PETN.
[a]
Compd. Tdec.
[8C]
d[b]
DHf8[c]
[kJgÀ1
P[d]
D[e]
IS[f]
[J]
OB[g]
[%]
[gcmÀ3
]
]
[GPa] [msÀ1
]
7
8
9
400
356
162
283
391
38
207
129
295
150
1.69
1.77
2.10
2.41
2.80
1.82
1.80
1.79
1.65
1.77
695 (0.9)
463 (2.3)
–
–
–
710 (2.1)
711 (2.3)
618 (2.1)
19.85 7032
19.41 7160
19.0
18.0 À107
À92
–
–
–
–
–
–
7.5
5.0
3.5
3.0
5.0
5.5
15.0
4.0
À89
À76
À46
À28
À63
À46
À74
5
10
11
13
14
16
TNT
PETN
31.20 8376
13.67 6234
Received: June 30, 2012
Revised: August 1, 2012
Published online: && &&, &&&&
26.9
7946
À67 (0.3) 19.53 6881
À407(0.4) 31.39 8564
[a] Thermal decomposition temperature under nitrogen gas (DSC,
58CminÀ1). [b] From gas pycnometer (258C). [c] Heat of formation
(calculated with Gaussian03). [d] Calculated detonation pressure (Explo
5.05). [e] Calculated detonation velocity (Explo 5.05). [f] Impact sensi-
tivity (BAM Drophammer). [g] Oxygen balance.
Keywords: detonation properties · energetic materials ·
nitrogen-rich compounds · triazoles
.
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[8] R. D. Chapman, W. S. Wilson, J. W. Fronabarger, L. H. Merwin,
[1] a) C. Ye, H. Gao, J. A. Boatz, G. W. Drake, B. Twamley, J. M.
Shreeve, Angew. Chem. 2006, 118, 7420 – 7423; Angew. Chem.
Int. Ed. 2006, 45, 7262 – 7265; b) V. Thottempudi, T. K. Kim, K.-
H. Chung, J. S. Kim, Bull. Korean Chem. Soc. 2009, 30, 2152 –
2154; c) V. Thottempudi, H. Gao, J. M. Shreeve, J. Am. Chem.
Soc. 2011, 133, 6464 – 6471; d) V. Thottempudi, J. M. Shreeve, J.
Am. Chem. Soc. 2011, 133, 19982 – 19992; e) V. Thottempudi,
J. M. Shreeve, Synthesis 2012, 1253 – 1257.
[2] a) N. V. Latypov, J. Bergman, A. Langlet, U. Wellmar, U. Bemm,
Tetrahedron 1998, 54, 11525 – 11536; b) C. H. Lim, T. K. Kim,
K. H. Kim, K.-H. Chung, J. S. Kim, Bull. Korean Chem. Soc.
2010, 31, 1400 – 1402; c) Y.-H. Joo, J. M. Shreeve, J. Am. Chem.
Soc. 2010, 132, 15081 – 15090.
[3] a) H. Gao, J. M. Shreeve, Chem. Rev. 2011, 111, 7377 – 7436;
b) N. Fischer, K. Karaghiosoff, T. M. Klapçtke, J. Stierstorfer, Z.
Anorg. Allg. Chem. 2010, 636, 735 – 749; c) G. Holl, T. M.
Klapçtke, K. Polborn, C. Rienacker, Propellants Explos. Pyro-
tech. 2003, 28, 153 – 156; d) K. Karaghiosoff, T. M. Klapçtke, A.
Michailovski, H. Nçth, M. Suter, Propellants Explos. Pyrotech.
2003, 28, 1 – 6.
G. S. Ostrom, Thermochim. Acta 2002, 384, 229 – 243.
[9] a) J. B. Pedley, Theromochemical Data and Structures of Organic
Compounds, Vol. 1, Thermodynamic Research College, College
Station, 1994; b) P. Jiminez, M. V. Roux, C. J. Turrion, J. Chem.
Thermodyn. Mater. 1991, 9, 415 – 428.
[10] Y. Ishikawa, M. J. McQuaid, J. Mol. Struct. 2007, 818, 119 – 124.
[11] a) H. Gao, Y. H. Joo, B. Twamley, Z. Zhou, J. M. Shreeve,
Angew. Chem. 2009, 121, 2830 – 2833; Angew. Chem. Int. Ed.
2009, 48, 2792 – 2795; b) Y. Zhang, J. M. Shreeve, Angew. Chem.
2011, 123, 965 – 967; Angew. Chem. Int. Ed. 2011, 50, 935 – 937.
[12] J. P. Agrawal, R. D. Hodgson, Organic Chemistry of Explosives,
Wiley, Chichester, 2007.
[13] V. Chmatal, Z. J. Allan, F. Muzik, Collect. Czech. Chem.
Commun. 1959, 24, 494 – 501.
[14] V. A. Samsonov, L. B. Volodarsky, V. L. Korolev, G. Hisamutdi-
nov, Kh. Khim. Geterotsik. Soedin. 1993, 10, 1364 – 1367.
[15] K. Caron, V. Lachapelle, J. F. Keillor, Org. Biomol. Chem. 2011,
9, 185 – 197.
[16] A. Rivera, Y. Duarte, D. Gonzalez-Salas, J. Rios-Motta, G.
Zaragoza, Molecules 2009, 14, 1234 – 1244.
[4] a) D. E. Chavez, A. M. Hiskey, D. Naud, Propellants Explos.
Pyrotech. 2004, 29, 209 – 215; b) D. E. Chavez, M. A. Hiskey, J.
Energ. Mater. 1999, 17, 357 – 377; c) A. Hammerl, T. M. Kla-
pçtke, H. Nçth, M. Warchhold, Inorg. Chem. 2001, 40, 3570 –
3575.
[5] a) J. Kçhler, R. Meyer, Explosivstoffe, 7th ed., VCH, Weinheim,
1991; b) M. H. V. Huynh, M. A. Hiskey, E. L. Hartline, D. P.
Montoya, R. Gilardi, Angew. Chem. 2004, 116, 5032 – 5036;
Angew. Chem. Int. Ed. 2004, 43, 4924 – 4928.
[6] a) M. J. Kamlet, S. J. Jacobs, J. Chem. Phys. 1968, 48, 23 – 35;
b) M. J. Kamlet, S. J. Jacobs, J. Chem. Phys. 1968, 48, 36 – 42;
c) H. Gao, C. Ye, O. D. Gupta, J.-C. Xiao, M. A. Hiskey, B.
Twamley, J. M. Shreeve, Chem. Eur. J. 2007, 13, 3853 – 3860.
[7] M. Y. Nagamachi, J. I. Oliveira, A. M. Kawamoto, R. C. Dutra,
J. Aerosp. Technol. Manage. 2009, 1, 153 – 160.
[17] a) C. W. Rees, R. C. Storr, J. Chem. Soc. C 1969, 1474 – 1477;
b) A. R. Katritsky, M. V. Voronkov, A. Pastor, D. Tatham,
Heterocycles 1999, 51, 1877 – 1882; c) R. Ulagi, P. Kuselan, C.
Karunakaran, Monatsh. Chem. 2001, 132, 799 – 804.
[18] S. Q. Wang, S. T. Thynell, Combust. Flame 2012, 159, 438 – 447.
[19] a) http://www.bam.de; b) A portion of 20 mg of alkoxy nitro-
iminotetrazole and their salts was subjected to a drop-hammer
test using a 5 or 10 kg weight dropped. A range in impact
sensitivities according to the UN Recommendations was applied
(insensitive > 40 J; less sensitive ꢀ 35 J; sensitive ꢀ 4 J; very
sensitive ꢁ 3 J).
[20] H. H. Krause in Energetic Materials (Ed.: U. Teipel), VCH,
Weinheim, 2005, pp. 1 – 25.
Angew. Chem. Int. Ed. 2012, 51, 1 – 6
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

.
Angewandte
Communications
Communications
Energetic Materials
V. Thottempudi, F. Forohor, D. A. Parrish,
J. M. Shreeve*
&&&& — &&&&
Tris(triazolo)benzene and Its Derivatives:
High-Density Energetic Materials
High-performance explosives: Tris-
(triazolo)benzene was synthesized and
converted to its trinitro and trichloro
derivatives (see scheme; R=NO2, Cl).
The heats of formation of this “high-
nitrogen” compounds were calculated
and combined with experimentally deter-
mined densities to determine detonation
pressures and velocities. They exhibit
high density, good thermal stability, high
heats of formation, and moderate to good
detonation properties.
6
www.angewandte.org
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2012, 51, 1 – 6
These are not the final page numbers!