Synthesis of isomeric 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl] nitrobenzenes by nitration of the corresponding isomeric 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl]benzenes

Article abstract of DOI:10.1007/s11172-011-0055-5

Isomeric 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl]nitro(dinitro)benzenes were synthe-sized in high yields by nitration of the corresponding 1,3- and 1,4-bis[3(4)-nitrofuroxan-4(3)-yl]benzenes with a mixture of 100% nitric acid and concentrated sulfuric

Full text of DOI:10.1007/s11172-011-0055-5

Russian Chemical Bulletin, International Edition, Vol. 60, No. 2, pp. 339—344, February, 2011
339
Synthesis of isomeric 1,3ꢀ and 1,4ꢀbis[3(4)ꢀnitrofuroxanꢀ
4(3)ꢀyl]nitrobenzenes by nitration of the corresponding isomeric
1,3ꢀ and 1,4ꢀbis[3(4)ꢀnitrofuroxanꢀ4(3)ꢀyl]benzenes
A. O. Finogenov,a M. A. Epishina,a I. V. Ovchinnikov,a A. S. Kulikov,a I. V. Anan´ev,b and N. N. Makhovaa
aN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5328. Eꢀmail: mnn@ioc.ac.ru
bA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5085. Eꢀmail: kostya@xrlab.ineos.ac.ru
Isomeric 1,3ꢀ and 1,4ꢀbis[3(4)ꢀnitrofuroxanꢀ4(3)ꢀyl]nitro(dinitro)benzenes were syntheꢀ
sized in high yields by nitration of the corresponding 1,3ꢀ and 1,4ꢀbis[3(4)ꢀnitrofuroxanꢀ4(3)ꢀ
yl]benzenes with a mixture of 100% nitric acid and concentrated sulfuric acid. The influence of
3ꢀ and 4ꢀnitrofuroxanyl fragments on the regioselectivity of the nitration was revealed. The
structure of 1,3ꢀbis(4ꢀnitrofuroxanꢀ3ꢀyl)ꢀ4ꢀnitrobenzene was confirmed by Xꢀray diffraction
analysis. 1,3ꢀ and 1,4ꢀBis(3ꢀnitrofuroxanꢀ4ꢀyl)nitrobenzenes underwent thermal isomerization
to more thermodynamically favorable 1,3ꢀ and 1,4ꢀbis(4ꢀnitrofuroxanꢀ3ꢀyl)nitrobenzenes.
Key words: isomeric 1,3ꢀ and 1,4ꢀbis[3(4)ꢀnitrofuroxanꢀ4(3)ꢀyl]benzenes, 1,3ꢀ and
1,4ꢀbis[3(4)ꢀnitrofuroxanꢀ4(3)ꢀyl]nitro(dinitro)benzenes, nitration, regioselectivity, thermal
isomerization, Xꢀray diffraction analysis.
Recently,1,2 we have developed a convenient approach
to the structures bearing two nitrofuroxanyl fragments in
one aromatic ring, viz., 1,3ꢀ (1a,c) and 1,4ꢀbis(3ꢀnitroꢀ
furoxanꢀ4ꢀyl)benzenes (1b) and their isomers 1,3ꢀ (2a,c)
and 1,4ꢀbis(4ꢀnitrofuroxanꢀ3ꢀyl)benzenes (2b). Comꢀ
pounds 1a—c were synthesized by nitrosation of tetrapoꢀ
tassium salts 3a—c, which have been prepared from the
known2 1,3ꢀ and 1,4ꢀdi(hydroximoyl chlorides) 4a—c.
Thermal isomerization of 3ꢀnitroisomers 1a—c resulted
in thermodynamically more stable compounds 2a—c
(Scheme 1).
meric nitrofuroxanyl fragments as well as the Me groups
(compounds 1c and 2c) on the regioselectivity of the nitraꢀ
tion reactions. The compounds bearing the nitrofuroxanyl
substituents along with the nitro groups in one benzene
ring are of interest as prospective energetic compounds.
Earlier,3 the nitration of 3ꢀarylꢀ4ꢀnitrofuroxans (aryl is
phenyl (5a), 2ꢀnitrophenyl (5b), 4ꢀnitrophenyl (5c),
and 3ꢀnitrophenyl (5d)) has been studied. A mixture of
equal volumes of 100% nitric acid and concentrated sulꢀ
phuric acid (the molar ratio substrate : HNO3 = 1 : 10)
was used in all cases. It was shown that the nitration of
4ꢀnitroꢀ3ꢀphenylfuroxan (5a) proceeded in high yields
even at 0 °C and afforded a mixture of approximately equal
amounts of 4ꢀnitroꢀ and 3ꢀnitrophenyl derivatives 5c
In the present work, we studied the possibility of aroꢀ
matic ring nitration of compounds 1a—c and 2a—c. In the
investigation, we planned to estimate the influence of isoꢀ
Scheme 1
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 332—337, February, 2011.
1066ꢀ5285/11/6002ꢀ339 © 2011 Springer Science+Business Media, Inc.

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Finogenov et al.
and 5d. Thus, the 4ꢀnitrofuroxanyl fragment is a mixed
ortho(para)ꢀ and metaꢀdirecting group in the nitration of
the phenyl fragment. In the nitration of 2ꢀ, 3ꢀ, and
4ꢀnitrophenyl derivatives, it is the nitro group already
present in the benzene ring that determined which posiꢀ
tion the second nitro group will occupy and the reaction
resulted in metaꢀdinitrocompounds 5e,f only. The existing
nitro group in compounds 5b—d was deactivating, thus,
the introduction of the second nitro group required that
the temperature was increased to 35—45 °C (for 3ꢀnitroꢀ
phenyl derivative 5d) and to 25—30 °C (for 2ꢀ and 4ꢀnitroꢀ
phenyl compounds 5b,c) (Scheme 2).
In the present work, we used a mixture of equal volꢀ
umes of 100% nitric acid and 97% sulphuric acid for the
nitration of compounds 1a—c and 2a—c bearing two
nitrofuroxanyl fragments at one aromatic ring. However,
the deactivating effect of two nitrofuroxanyl groups of
compounds 1a—c and 2a—c required performing the
benzene ring nitration at higher temperatures (50—55 °C)
as compared with 3ꢀarylꢀ4ꢀnitrofuroxanyl derivatives
5a—d (0—45 °C). In all cases, the mononitrocompounds
6a—c and 7a—c were obtained in high yields (80—90%)
(Scheme 3).
ments in positions 1 and 3 of the benzene ring exhibit
a concerted ortho(para)ꢀdirecting effect in the aromatic
ring nitration in contrast to the 3ꢀnitrofuroxanꢀ4ꢀyl fragꢀ
ments, which are metaꢀdirecting (see Scheme 3). This difꢀ
ferent directing ability of the isomers of the nitrofuroxans
is cased by the features of distribution of the electron denꢀ
sity in the furoxan ring. As a whole, the furoxan ring (simꢀ
ilarly to the furazan ring) has a strong electronꢀwithꢀ
drawing effect. However, it is the higher electron density4
on the С(3) atom of the furoxan ring due to the resonance
influence of the Nꢀoxide fragment that activates the orthoꢀ
and paraꢀpositions of the aromatic ring of compound 2a
for electrophilic attack.
Since the regioselectivity of the nitration of 1,4ꢀisoꢀ
mers 1b and 2b is invariant, the new nitro groups occupy
only position 2 of the aromatic rings in compounds 6b and
7b regardless of the position of the nitro group in the nitroꢀ
furoxanyl fragment of the starting compounds. In the niꢀ
tration of the Meꢀsubstituted derivatives 1c and 2c, the
direction of the introduction of the nitro groups was enꢀ
tirely defined by the electron donating effect of the Me
group so that 4ꢀnitroderivatives 6c and 7c formed. The
nitration of compound 1c results in dinitro compound 6d
in a moderate yield along with mononitro compound 6c.
However, our attempts to completely transform compound 6c
into dinitro derivative 6d by the nitration failed, the first
nitro group is deactivating and the subsequent nitration
required increasing the temperature, which in turn cased
the isomerisation of the furoxan rings (see Scheme 3).
Another convenient approach to the 4ꢀnitrofuroxan
derivatives is the thermal isomerization of their 3ꢀnitroꢀ
The regioselectivity of the aromatic ring nitration deꢀ
pended on the structures of the starting compounds. It
was found that the nitration of 1,3ꢀbis(3ꢀnitrofuroxanꢀ4ꢀ
yl)benzene (1a) bearing the furoxanꢀ4ꢀyl moieties resultꢀ
ed in 5ꢀnitro isomer 6a, while the nitration of 1,3ꢀbisꢀ
(4ꢀnitrofuroxanꢀ3ꢀyl)benzene (2a) where the aromatic ring
bears the furoxanꢀ3ꢀyl fragment afforded 4ꢀnitro derivaꢀ
tive 7a. It is evident that two 4ꢀnitrofuroxanꢀ3ꢀyl fragꢀ
Scheme 2
i. HNO3, H2SO4

Bis[3(4)ꢀnitrofuroxanꢀ4(3)ꢀyl]nitrobenzenes
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 2, February, 2011
341
Scheme 3
i. HNO3, H2SO4
furoxanyl analogs. Nitrofuroxanyl derivatives 6a—c were
easily transformed into the more thermodynamically stable
4ꢀnitro isomers 7a—c in almost quantitative yields after
heating under reflux for 5 h in toluene (Scheme 4).
The structures of the prepared compounds were conꢀ
firmed by elemental analysis and spectral data (Tables 1
and 2); the structure of compound 7a was also confirmed
by Xꢀray diffraction analysis. Though the mass spectra of
all synthesized compounds have no peaks of molecular
ions, all of them contain the peaks of fragment ions formed
upon the loss of one or several NO and NO2 fragments
from the molecular species (see Table 2). This is one of
the most characteristic properties of the nitrofuroxan deꢀ
rivatives.4
Scheme 4
The Xꢀray diffraction analysis data indicate that the
structure of compound 7a is 2,4ꢀbis(4ꢀnitrofuroxanꢀ3ꢀyl)ꢀ
1ꢀnitrobenzene (Fig. 1). The furoxan rings and the nitro
groups of these fragments are coplanar. The benzene ring
substituents have different orientation relative to the plane
of the aromatic ring, the torsion angles are 21.1(2)° for the
nitro group and 70.6(3) and 48.7(3)° for the nitrofuroxan
fragments. Evidently, this difference is caused by steric
repulsion between the furoxan substituent at the C(7) atom
and the nitro group at the C(6) atom and also the presence
of numerous short intermolecular interactions O...O in
the crystal lattice. Notably, the furoxan ring which forms
the larger angle with the benzene ring is disordered over
R = H (a,b), Me (c)

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Finogenov et al.
Table 1. Yields and selected physicochemical characteristics of 1,3ꢀ and 1,4ꢀbic[3(4)ꢀnitrofuroxanꢀ
4(3)ꢀyl]nitro(dinitro)benzenes 6a—d and 7a—c
Compound
Yield
(%)
M.p.
/°С
Rf
Found
Calculated
Molecular
formula
(%)
C
H
N
6a
6b
6с
6d
7a
7b
7с
87
85
83
14
81
90
80
154—155
164—166
107—108
171—172
166—167
186—188
125—127
0.16a
0.40a
0.31b
0.11b
0.17b
0.17b
0.18b
31.37
31.51
31.52
31.51
30.12
30.01
33.47
33.43
31.64
31.51
31.42
31.51
33.38
33.43
0.76
0.79
0.81
0.79
0.87
0.92
1.35
1.28
0.83
0.79
0.74
0.79
1.24
1.28
25.74
25.72
25.71
25.72
25.52
25.46
24.68
24.81
25.70
25.72
25.78
25.72
24.83
24.81
С10H3N7O10
С10H3N7O10
С11H5N7O10
С11H4N8O12
С10H3N7O10
С10H3N7O10
С11H5N7O10
a Eluent — CCl4—EtOAc, 5 : 1. b Eluent — CCl4—EtOAc, 10 : 1.
Table 2. 1H, 13C, 14N NMR (DMSOꢀd6), IR, and MS data of compounds 6a—d and 7a—c
Compound
IR, ν/ cm–1
1H NMR, δ, J/Hz
[MS, m/z (Irel (%))]
13C NMR, δ
[14N NMR, δ, Δν1/2 /Hz]
6a
3420, 1644, 1628,
1544, 1420, 1352,
1264, 1172, 1040,
1016, 908, 856,
820, 752, 728,
692, 668
8.62 (s, 1 H, C(2), Ar);
8.98 (s, 2 H, C(4), С(6), Ar)
[351 [M – NO]+ (2),
305 [M – NO – NO2]+ (12)
245 [M – 3 NO – NO2]+ (19),
229 [M – 2 NO – 2 NO2]+ (9)
173 (100), 144 (17), 127 (72),
100 (39)]
126.89 (C(3) of the furoxan ring);
127.60, 136.01, 136.62 (C(1),
C(2), C(3), C(4), С(6), Ar);
147.63 (СNO2, Ar);
150.47 (C(4) of the furoxan ring)
[–36.75, Δν1/2 = 22.4]
6b
3440, 1636, 1624,
1536, 1424, 1348,
1272, 1204, 1016,
988, 848, 804, 788,
732, 668
8.16, 8.47 (both d, 2 H, C(2),
С(3), Ar, 3J = 7.8);
8.92 (s, 1 H, C(6), Ar)
[305 [M – NO – NO2 ]+ (63),
263 [M – NO – NO2 – CNO]+ (61),
245 [M – 3 NO – NO2]+ (25),
229 [M – 2 NO – 2 NO2]+ (12),
201 (22), 187 (43), 173 (79),
169 (90), 144 (90), 127 (61),
100 (100)]
126.12 (C(3) of the furoxan ring);
126.56 (C(3) of the furoxan ring);
121.99, 129.52, 133.82, 135.08,
135.71 (C(1), C(2), C(3), C(4),
С(6), Ar); 146.72 (СNO2, Ar);
149.96 (C(4) of the furoxan ring);
150.28 (C(4) of the furoxan ring)
[–38.59, Δν1/2 = 20.6]
6c
3430, 3076, 1636,
1544, 1516, 1428,
1348, 1264, 1192,
1012, 904, 852, 820,
736, 668
2.61 (s, 3 H, CH3); 8.22 (s, 1 H,
C(6), Ar); 8.29 (s, 1 H, C(2), Ar)
[318 [M – NO – NO2 – 1]+ (14),
272 [M – NO – 2 NO2 – 1]+ (35),
242 [M – 2 NO – 2 NO2–1]+ (38),
169 (100), 157 (37), 142 (37),
129 (42), 114 (86)]
23.42 (CH3); 124.10 (C(3)
of the furoxan ring); 126.46
(C(3) of the furoxan ring);
127.77, 133.19, 136.22, 138.54,
142.10 (C(1), C(2), C(3), C(5),
С(6), Ar); 153.53 (СNO2, Ar);
155.27 (C(4) of the furoxan ring);
155.63 (C(4) of the furoxan ring)
[–36.73, Δν1/2 = 15.0]
(to be continued)

Bis[3(4)ꢀnitrofuroxanꢀ4(3)ꢀyl]nitrobenzenes
Russ.Chem.Bull., Int.Ed., Vol. 60, No. 2, February, 2011
343
Table 2 (continued)
Compound
IR, ν/ cm–1
1H NMR, δ, J/Hz
[MS, m/z (Irel (%))]
13C NMR, δ
[14N NMR, δ, Δν1/2 /Hz]
6d
3400, 3240, 3088,
2920, 1636, 1544,
1444, 1352, 1268,
1172, 1104, 1012,
916, 888, 792
2.72 (s, 3 H, CH3); 8.09 (s, 1 H,
C(2), Ar)
[343 [M – 2 NO – NO2 – 1]+ (1),
318 [M – NO – 2 NO2]+ (5),
181 (7), 157 (50),
20.99 (CH3); 127.26 (C(3) of the
furoxan ring); 122.25, 137.15, 145.53
(C(1), C(2), C(3), C(5), Ar); 147.48
(СNO2, Ar); 150.51 (C(4) of the
furoxan ring)
129 (11), 114 (100)]
[–38.62, Δν1/2 = 15.5]
7а
3420, 3100, 2928,
2872, 1644, 1572,
1616, 1484, 1360,
1280, 1128, 1024,
984, 824, 740
8.39, 8.69 (both d, 2 H, C(5),
С(6), Ar, 3J = 9.1); 8.41 (s, 1 H,
C(2), Ar)
108.37 (C(3) of the furoxan ring);
109.63 (C(3) of the furoxan ring);
115.77, 126.45, 127.83, 134.54, 135.58
(C(1), C(2), C(3), C(5), C(6), Ar);
148.10 (СNO2, Ar);
158.15 (C(4) of the furoxan ring);
158.58 (C(4) of the furoxan ring)
[–35.54, Δν1/2 = 32.3]
[351 [M–NO]+ (2),
305 [M – NO – NO2]+ (6),
259 [M – NO – 2 NO2]+ (13),
245 [M – 3 NO – NO2]+ (4),
229 [M – 2 NO – 2 NO2 ]+ (15),
185 (19), 173 (31), 144 (58),
127 (80), 100 (100)]
7b
3440, 3116, 1636,
1616, 1576, 1548,
1520, 1492, 1352,
1308, 1280, 1128,
1076, 1012, 984,
888, 840, 792,
8.27, 8.44 (both d, 2 H,
C(5), С(6), Ar)
8.94 (s, 1 H, C(3), Ar)
[305 [M – NO – NO2 ]+ (5.5),
275 [M – 2 NO – NO2]+ (5.5),
259 [M – NO – 2 NO2]+ (9),
229 [M – 2 NO – 2 NO2]+ (9),
187 (30), 173 (82), 144 (46),
127 (100), 100 (93)]
108.58 (C(3) of the furoxan ring);
109.56 (C(3) of the furoxan ring);
117.83, 126.00, 127.62, 133.99,
136.24 (C(1), C(2), C(3), C(4), C(6)
Ar); 146.77 (СNO2, Ar); 154.87
(C(4) of the furoxan ring);
728, 660
155.40 (C(4) of the furoxan ring)
[–35.65, Δν1/2 = 31.0]
7c
3430, 2924, 2876,
1636, 1624, 1576,
1532, 1512, 1352,
1304, 1192, 1080,
1052, 1024, 912,
896, 828, 776,
752, 716, 684,
664
2.58 (s, 3 Н, Ме); 8.21, 8.28
(both s, 2 H, C(2),
С(6), Ar)
[364 [M – NO – 1]+ (1),
349 [M – NO2]+ (1),
319 [M – NO – NO2]+ (34),
273 [M – NO – 2 NO2]+ (19),
243 [M – 2 NO – 2 NO2]+ (27),
217 (17), 201 (20), 183 (31),
170 (85), 158 (41), 142 (67),
129 (44), 114 (94), 91 (100)]
18.62 (CH3); 116.45 (C(3) of the
furoxan ring); 120.39 (C(3) of the
furoxan ring); 128.14, 129.04,
131.39, 134.67, 137.48, (C(1), C(2),
C(3), C(5), C(6), Ar); 149.16 (СNO2,
Ar); 150.85 (C(4) of the furoxan ring);
151.30 (C(4) of the furoxan ring)
[–35.33, Δν1/2 = 39.5]
O(5)
two positions (see Experimental), which makes impossiꢀ
ble detailed analysis of intraꢀ and intermolecular inꢀ
teractions.
O(6)
N(4)
C(5)
O(8)
C(9)
In conclusion, we studied the aromatic ring nitration
of isomeric 1,3ꢀ and 1,4ꢀbis[3(4)ꢀnitrofuroxanꢀ4(3)ꢀyl]ꢀ
benzenes, which revealed the influence of the 3ꢀ and 4ꢀnitroꢀ
furoxanyl fragments on the direction of the nitration, and
prepared the corresponding 1,3ꢀ and 1,4ꢀbis[3(4)ꢀnitroꢀ
furoxanꢀ4(3)ꢀyl]nitrobenzenes in high to excellent yields.
N(6)
O(9)
C(4)
C(3)
C(6)
C(7)
C(10)
O(1)
N(7)
N(5)
C(2)
C(1)
C(8)
N(3)
N(1)
N(2)
O(10)
O(7)
O(2)
O(4)
Experimental
O(3)
Fig. 1. General view of compound 7a. Nonꢀhydrogen atoms are
given with 50% probability thermal ellipsoids. The disorder of
the nitrofuroxan fragments is not shown.
IR spectra were recorded on a URꢀ20 spectrometer (KBr
pellets). NMR spectra were recorded on Bruker WMꢀ250 (1H,

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Finogenov et al.
250 MHz) and Bruker AMꢀ300 (13C, 75.5 MHz; 14N, 21.5 MHz)
spectrometers in DMSOꢀd6 using Me4Si (1H and 13C) as the
internal standard or MeNO2 (14N) as the external standard. Mass
spectra were obtained on a Varian MAT CH 6 instrument (EI,
70 eV). Thin layer chromatography was performed on Silufol
UVꢀ254 plates with the visualization by UV light.
Isomerisation of 1,3(1,4)ꢀ[bis(3ꢀnitrofuroxanꢀ4ꢀyl]nitroꢀ
benzenes 6a—c into 1,3(1,4)[bis(4ꢀnitrofuroxanꢀ3ꢀyl]nitrobenzeꢀ
nes 7a—c (general procedure). A suspension of furoxans 6a—c
(1 mmol) in toluene (10 mL) was refluxed for 5 h. The reaction
mixture was cooled, furoxans 7a—c were filtered off and dried
on air. Furoxans 7a—c were obtained in 94—96% yields and
were identical to those prepared by the nitration judging by the
spectral data.
Xꢀray diffraction study. The crystals of compound 7a at 100 K
are orthorhombic, space group Pbca, a = 13.4057(16),
b = 10.6094(13), c = 19.251(2) Å, V = 2738.0(6) Å3, Z = 8
(Z´ = 1), dcalc = 1.849 g cm–3, μ(MoKα) = 1.70 cm–1, F(000) =
= 1536. The intensities of 28515 reflections were measured at
100 K on a SMART APEX II CCD diffractometer (λ(MoKα) =
= 0.71072 Å, ωꢀscanning mode, 2θ < 60°) and 3291 independent
reflections (Rint = 0.0551) were used for the further refinement.
The structure was solved by the direct methods and refined by
the fullꢀmatrix leastꢀsquares method with anisotropic displaceꢀ
ment parameters based on Fhkl2. The furoxan fragment in the
position 2 of the benzene ring is disordered over two directions
with occupancy factors of 0.8, 0.2 that could be described as
superposition of two nitrofuroxan rings bearing different locaꢀ
tion of nitroꢀ and nitroxyl groups relative to the plane of the
benzene ring. All hydrogen atoms were positioned geometrically
and refined using fixed thermal parameters Biso = 1.2Ciso anisoꢀ
tropically. The final uncertainty factors for compound 7a were
R1 = 0.0454 (calculations based on Fhkl for 2742 reflections with
I > 2σ(I)), wR2 = 0.1130 (calculations based on Fhkl2 for all 3291
reflections), GOF = 1.015. All calculation were carried out usꢀ
ing the SHELXTL 5.10 program package.5 The coordinates of
the atoms and details of Xꢀray diffraction experiment have been
deposited with the Cambridge Crystallographic Data Centre
(CCDC 776986).
Synthesis of 1,3(1,4)ꢀ[bis(3(4)nitrofuroxanꢀ4(3)yl]nitrobenzeꢀ
nes 6a—d and 7a—c (general procedure). 100% HNO3 (10 mL)
was gradually (3—4 min) added to a solution of furoxan 1a—c or
2a—c (2 mmol) in 97% H2SO4 (10 mL) at room temperature.
Temperature was increased to 50—55 °C and the reaction mixture
was stirred for 1 h. After cooling to room temperature, the reacꢀ
tion mixture was poured onto ice (10 mL). The solid was filtered
off and washed with large amount of water and dried on air.
According to TLC, the nitration of compound 1c resulted in
a mixture of 6c and 6d. These compounds were separated by
preparative TLC (CCl4—EtOAc, 10 : 1).
This work was partially financially supported by the
Division of Chemistry and Materials Science of the Rusꢀ
sian Academy of Sciences (Program "Development of
a Scientific Basis for the Preparation of a New Generation
of Highly Energetic Materials").
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Received May 26, 2010;
in revised form November 26, 2010