Synthesis and structural characterization of N-amino compounds

Article abstract of DOI:10.14233/ajchem.2014.16529

Seven N-amino compounds were successfully synthesized via N-amination reaction. The structures of target compounds and intermediates were characterized by ¹H NMR, ¹³C NMR, IR, elementary analysis, MS and X-ray single-crystal diffraction analysis. The single crystals of 3,5-diamino-1,2,4-triazole and 3,5-dinitro-1,2,4-triazole were obtained. Crystal data of 3,5-diamino-1,2,4-triazole: C₂H₅N₅, M_r = 99.11, Monoclinic, P2(1)/c, a = 10.652(4), b = 4.3411(14), c = 10.822(4) ?, α = 90(4), β = 118.714(4), γ = 90deg;, V = 0.4389(2) nm³, Z = 4, Dc = 1.500 g cm^-3, μ = 0.113 mm^-1, F(000) = 208, R = 0.0354 and wR = 0.0936. Crystal data of 3,5-dinitro-1,2,4-triazole: C₂H₃N₅O₅, M_r = 177.09, Orthorhombic, P2(1)2(1)2(1), a = 4.937(3), b = 9.344(5), c = 140447(7) ?, α = 90, β = 90, γ = 90°, V = 0.6665(6) nm³, Z = 4, Dc = 1.765 g cm^-3, μ = 0.171 mm^-1, F(000) = 360, R = 0.0555 and wR = 0.1772.

Full text of DOI:10.14233/ajchem.2014.16529

Asian Journal of Chemistry; Vol. 26, No. 21 (2014), 7151-7156
ASIAN JOURNAL OF CHEMISTRY
http://dx.doi.org/10.14233/ajchem.2014.16529
Synthesis and Structural Characterization of N-Amino Compounds
*
YA-NAN LI , NING LIU, PENG-FEI SU, YING-LEI WANG, ZHONG-XUE GE, HUI LI and BO-ZHOU WANG
Xi'an Modern Chemistry Research Institute, Xi'an 710065, P.R. China
*Corresponding author: Fax: +86 29 88220423; Tel: +86 29 88291306; E-mail: lyn2003080094@126.com
Received: 15 October 2013;
Accepted: 11 March 2014;
Published online: 30 September 2014;
AJC-16091
Seven N-amino compounds were successfully synthesized via N-amination reaction. The structures of target compounds and intermediates
were characterized by 1H NMR, 13C NMR, IR, elementary analysis, MS and X-ray single-crystal diffraction analysis. The single crystals
of 3,5-diamino-1,2,4-triazole and 3,5-dinitro-1,2,4-triazole were obtained. Crystal data of 3,5-diamino-1,2,4-triazole: C2H5N5, Mr = 99.11,
Monoclinic, P2(1)/c, a = 10.652(4), b = 4.3411(14), c = 10.822(4) Å, α = 90(4), β = 118.714(4), γ = 90°, V = 0.4389(2) nm3, Z = 4, Dc
= 1.500 g cm-3, µ = 0.113 mm-1, F(000) = 208, R = 0.0354 and wR = 0.0936. Crystal data of 3,5-dinitro-1,2,4-triazole: C2H3N5O5, Mr =
177.09, Orthorhombic, P2(1)2(1)2(1), a = 4.937(3), b = 9.344(5), c = 140447(7) Å, α = 90, β = 90, γ = 90°, V = 0.6665(6) nm3, Z = 4, Dc
= 1.765 g cm-3, µ = 0.171 mm-1, F(000) = 360, R = 0.0555 and wR = 0.1772.
Keywords: N-amination reaction, N-amino compounds, Synthesis, Characterization, Crystal structure.
In this paper, seven N-amino compounds were synthesized
INTRODUCTION
using imino compounds as starting materials via N-amination
Nitrogen-rich heterocyclic-based compounds have most
reaction. The structures of target compounds were characterized
by IR, 1H NMR, 13C NMR, elemental analysis and MS. Two
often been utilized in energetic compounds due to their higher
positive heats of formation, density and oxygen balance than
single crystals of 3,5-diamino-1,2,4-triazole (DAT) and 3,5-
those of their carbocyclic analogues1. Nitrogen-rich com-
dinitro-1,2,4-triazole (DNT·H2O) were grown and their crystal
pounds form a unique class of energetic materials whose energy
structure were characterized by single-crystal X-ray diffraction
analysis13,14
.
is derived from their high heats of formation directly attri-
butable to the large number of inherently energetic C-N, N-N,
C=N and N=N bonds2. Smaller amounts of hydrogen and
carbon contribute to a better oxygen balance than normally is
found with their carbocyclic analogues, a higher percentage
of their decomposition products will be N21,2. Pyrazole, triazole,
tetrazole, tetrazine, furazan and furoxan derivatives are inte-
resting high energy materials due to their highly positive heats
of formation, high nitrogen content and good thermal stability
deriving from their aromaticity3-7.
Recently, the combination of an azo group with high-nitrogen
heteroaromatic rings has been extensively studied because the
azo linkage not only desensitizes but also dramatically increases
the heats of formation of high-nitrogen compounds, such as
3,3'-azobis(6-amino-1,2,4,5-tetrazine)8, 4,4'-azobis-1,2,4-
triazole9, 1,1'-azobis(3-nitro-1,2,4,5-tetrazole)10, 1,1'-azobis-
1,2,3-triazole3, 4,4',6,6'-tetra(azido)azo-1,3,5-triazine11, 1,1'-
azobis(tetrazole)5. Most of the above compounds were synthe-
sized using the N-amino compounds as raw materials. N-
amination reaction is a effective method for obtaining N-amino
compounds using imino compounds as starting materials12.
EXPERIMENTAL
All reagents were purchased from commercial sources
and used without further purification. 1H NMR and 13C NMR
were obtained in DMSO-d6 on a Bruker AV 500 NMR spec-
trometer. Infrared spectra were obtained from KBr pellets on
a Nicolet NEXUS870 Infrared spectrometer in the range of
400-4000 cm-1. Elemental analyses (C, H and N) were perfor-
med on aVARI-El-3 elemental analyzer. Differential scanning
calorimetry (DSC) was carried out in a platinum sample
container using a Shimadzu DSC-60, the 1.0-1.5 mg sample
was heated at a rate of 10 °C/min. The data of single crystal
were collected on a Bruker SMARTAPEXII CCD X-ray diffrac-
tometer.
General procedure: Synthesis of DANT andADNT: 1,5-
diamino-3-nitro-1,2,4-triazole (DANT) and 1-amino-3,5-
dinitro-1,2,4-triazole (ADNT) were synthesized by the method
outlined in Scheme-I.
3,5-Diamino-1,2,4-triazole sulfate (DAT·1/2H2SO4) (32
g, 0.216 mol) was transferred into a three-necked round bottom

7152 Li et al.
Asian J. Chem.
NH2
H
N
H
N
H
N
N
NH2
NO2
NH2
NO
2
N
N
N
NH2OSO3H
NaNO2
H2SO4
N
NaOH
1/2 H2SO4
N
N
N
N
H2N
O2N
H2N
O2N
HDAT
DAT
DNT
ADNT
NH3
NH2
H
N
NH4
N
N
NH2
NH2
NO2
N
N
NH2OSO3H
N
NH2NH2-H2O
N
N
N
O2N
O2N
ANT
DANT
O2N
A DNT
Scheme-I: Synthetic route for ADNT and DANT
flask fitted with a mechanical stirrer and a dropping funnel
and then 274.5 mL of water was added. The solution was
cooled to 15 °C after the solid was dissolved. Solid sodium
hydroxide (8.72 g, 0.218 mol) was added to the reaction flask.
After the sodium hydroxide was added completely, the reaction
mixture was heated up to 40 °C and stirred for another 1.5 h.
The water was removed under reduced pressure and then 500
mL of methanol was added to solid, the methanol mixture
was heated up to 70 °C and stirred for another 2 h. The insoluble
solid was filtered, the methanol was removed under reduced
pressure and 12.6 g white solid of 3,5-diamino-1,2,4-triazole
(DAT) was obtained with a yield of 58.9 %. 1H NMR(DMSO-
d6, 500 MHz), δ : 5.227 (s, 4H, NH2), 10.810 (s, 1H, NH); 13C
NMR (DMSO-d6, 125 MHz), δ: 158.45; IR (KBr, νmax, cm-1),
3398, 3310 (-NH2), 3235 (-NH); Anal. calcd for C2H5N5: C
24.24, N 70.67, H 5.09; found C 24.11, N 70.61, H 5.13; MS
(m/z): 99 [M+].
To a solution of 54.2 g (0.786 mol) of sodium nitrite in
63.3 mL water at -10 to -5 °C, we added a solution of 8 g
(0.081 mol) of DAT in 169.5 mL 1.2 mol/L sulfuric acid for
1.5 h, the reaction mixture was heated up to 60 °C and stirred
for another 1 h, then cooled the reaction mixture to room
temperature. 26.9 mL 6 mol/L sulfuric acid and 4.7 g (0.048
mol) aminosulfuric acid were added to reaction system and
stirred for another 0.5 h, extracted with 90 × 5 mL of ether,
dried with magnesium sulfate and the solvent was removed
under reduced pressure and 7.89 g yellow oil 3,5-dinitro-1,2,4-
triazole (DNT) was obtained with a yield of 61.4 %. 1H NMR
(DMSO-d6, 500 MHz), δ: 6.424 (s, 1H, NH); 13C NMR
(DMSO-d6, 125 MHz), δ: 162.56; IR (KBr, νmax, cm-1), 3224
(-NH-), 1659, 1382 (-NO2);Anal. calcd for C2H3N5O5: C 13.57,
N 39.55, H 1.71; found C 13.73, N 38.91, H 2.13; MS (m/z):
159 [M+].
extracted with 30 × 5 mL of ether, dried with magnesium
sulfate and the solvent was removed under reduced pressure
and 0.053 g yellow solid 1-amino-3,5-dinitro-1,2,4-triazole
(ADNT) was obtained with a yield of 4.9 %. 1H NMR (DMSO-
13
d6, 500 MHz), δ: 6.369 (s, 1H, NH), 6.833 (s, 1H, NH); C
NMR (DMSO-d6, 125 MHz), δ: 155.31, 155.92; IR (KBr, νmax
,
cm-1), 3424, 3340, 3297, 3229 (-NH2), 1671 (C=N), 1520, 1313
(-NO2); Anal. calcd for C2H2N6O4: C 13.80, N 48.28, H 1.16;
found C 13.96, N 48.01, H 1.22; MS (m/z): 174 [M+].
To a solution of 135.6 g (1.965 mol) of sodium nitrite in
158.2 mL of water at -10 to -5 °C, we added a solution of 20 g
(0.202 mol) of DAT in 423.7 mL 1.2 mol/L sulfuric acid for
1.5 h. The reaction mixture was heated up to 60 °C and stirred
for another 1 h, then cooled the reaction mixture to room
temperature. 67.2 mL 6 mol/L sulfuric acid and 11.85 g (0.121
mol) aminosulfuric acid were added to reaction system and
stirred for another 0.5 h, extracted with 322.5 × 3 mL of tri-
octylamine and 265.5 mL toluene, dried with magnesium
sulfate overnight. The magnesium sulfate was filtered and the
filtrate reacted with excess ammonia to obtain the yellow solid,
dried in vacuum to give 25.1 g of 3,5-dinitro-1,2,4-triazole
ammonium (A⊕ DNT).
3,5-Dinitro-1,2,4-triazole ammonium (25.1g, 0.143 mol)
was transferred into a three-necked round bottom flask, then
65 mL 80 % of hydrazine hydrate was added. The reaction
mixture was heated up to 80 °C and stirred for another 2 h,
cooled to room temperature, adjusted to pH 1-2 by 36 % HCl.
The solid product was filtered, washed with cold water and
dried in vacuum to give 14 g yellow solid 3-amino-5-nitro-
1,2,4-triazole (ANT) with a yield of 76.1 %. m.p.: 234.6-235.9
1
°C. H NMR (DMSO-d6, 500 MHz), δ: 6.817 (s, 2H, NH2),
13.158 (s, 1H, NH); 13C NMR (DMSO-d6, 125 MHz), δ:
157.43, 160.90; IR (KBr, νmax, cm-1), 3453, 3330 (-NH2), 3272
(-NH-), 1519, 1313 (-NO2);Anal. calcd for C2H5N5O3: C 16.33,
N 47.62, H 3.43; found C 16.69, N 48.94, H 3.27; MS (m/z):
129 [M+].
3,5-Dinitro-1,2,4-triazole (DNT) (1 g, 6.289 mmol) was
transferred into a three-necked round bottom flask, then 22
mL of water and sodium hydroxide (1.38 g, 34.6 mmol) were
added. The reaction mixture was heated up to 50 °C and then
a solution of hydroxylamino-O-sulfuric acid (2.13 g, 18.87
mmol) in 5 mL of water was added for 10 min. The pH was
kept at 8-9 by the addition of 30 % sodium hydroxide solution.
The reaction solution was stirred at 50 °C for another 4 h,
To a solution of 1.5 g (11.6 mmol) of ANT in 28 mL of
water at room temperature, we added sodium hydroxide (2.8
g, 69.8 mmol), the reaction mixture was heated up to 50 °C,
then a solution of hydroxylamino-O-sulfuric acid (3.94 g,
34.88 mmol) in 7 mL of water was added. The reaction mixture

Vol. 26, No. 21 (2014)
Synthesis and Structural Characterization of N-Amino Compounds 7153
was stirred for another 4 h, cooled the reaction mixture to
room temperature, extracted with 40 × 5 mL of ethyl acetate,
dried with magnesium sulfate. The magnesium sulfate was
filtered and the solvent was removed under reduced pressure
and 0.69 g yellow solid 1,5-diamino-3-nitro-1,2,4-triazole
(DANT) was obtained with a yield of 41.2 %. 1H NMR (DMSO-
d6, 500 MHz), δ: 6.425 (s, 2H, NH2), 6.889 (s, 2H, NH2); 13C
mixture was poured into ice water, the yellow solid product
was filtered, washed with cold water and dried in vacuum to
give 137.1 g of 3,6-dinitropyrazolo[4,3-c] pyrazole (DNPP)
1
with a yield of 72.3 %. H NMR (DMSO-d6, 500 MHz), δ:
15.058 (s, 2H, 2NH); 13C NMR (DMSO-d6, 125 MHz), δ:
131.58, 137.89; IR (KBr, νmax, cm-1), 3266 (-NH-), 1548, 1521,
1373, 1348 (-NO2); Anal. Calcd for C4H2N6O4: C 24.24, N
NMR (DMSO-d6, 125 MHz), δ: 155.29, 155.89; IR (KBr, νmax
cm-1), 3426, 3338, 3228 (-NH2), 1670 (C=N), 1519, 1313
(-NO2); Anal. calcd for C2H4N6O2:C 16.67, N 58.32, H 2.80;
found C 16.37, N 58.46, H 2.91; MS (m/z): 144 [M+].
Synthesis ofADNP: 1-Amino-3,4-dinitropyrazole (ADNP)
was synthesized by the method outlined in Scheme-II.
,
42.42, H 1.01; found C 24.38, N 42.71, H 1.16; MS (m/z):
198 [M+].
To a solution of 4 g (0.0202 mol) of 3,6-dinitropyrazolo[4,3-
c]pyrazole (DNPP) and 6.42 g (0.0605 mol) of sodium
carbonate in 85 mL of water at 70-75 °C, we added a solution
of 9.14 g (0.0808 mol) of hydroxylamino-O-sulfuric acid in
32 mL of water for 20 min. The pH was kept at 8-9 by the
addition of sodium bicarbonate. The mixture was kept at 70-
75 °C for 2 h and was then cooled to 15-20 °C. The precipitate
was filtered off, washed with cold water and dried to give 0.57
g brown solid 1,4-diamino-3,6-dinitro pyrazolo[4,3-c]pyrazole
O2N
O2N
N
N
NH2OSO3H
NH2
N
NH
1
(DADNP) with a yield of 12.4 %. H NMR (DMSO-d6, 500
O2N
O2N
MHz), δ: 7.221(s, 4H, -2NH2); 13C NMR (DMSO-d6, 125 MHz),
δ: 128.49, 131.94; IR (KBr, νmax, cm-1), 3319, 3272 (-NH2), 1532,
1395 (-NO2); Anal. calcd for C4H4N8O4: C 21.05, N 49.12, H
1.75; found (%): C 21.09, N 48.57, H 1.98; MS (m/z): 228 [M+].
During the neutralization of the above alkaline filtrate
solution with hydrochloric acid, the monosubstitition product
of DNPP was separated. It was washed with cold water and
dried to give 0.71 g brown 1-amino-3,6-dinitropyrazolo[4,3-
c]pyrazole (ADNPP) with a yield of 16.5 %. 1H NMR (DMSO-
d6, 500 MHz), δ: 7.268 (s, 2H, NH2), 15.091 (s, 1H, NH); 13C
NMR (DMSO-δ6, 125 MHz), δ: 111.31 (s), 129.66 (s), 138.37
(s), 144.56 (s); IR (KBr, νmax, cm-1), 3513, 3318 (-NH2), 3169
(-NH), 1626 (C=N), 1529, 1392, 1357 (-NO2), 1239, 1172,
1033 (pyrazole ring); Anal. Calcd for C4H3N7O4: C 22.54, H
1.42, N 46.01; found C 22.47, H 1.51, N 46.09; MS (m/z):
213 [M+].
ADNP
DNP
Scheme-II: Synthetic route for ADNP
To a solution of 1 g (6.33 mmol) of 3,4-dinitropyrazole
(DNP) and 1.35 g (12.68 mmol) of sodium carbonate in 25
mL of water at 70-75 °C, we added a solution of 2.15 g (18.99
mmol) of hydroxylamino-O-sulfuric acid in 10.8 mL of water
for 15 min. The pH was kept at 8-9 by the addition of sodium
bicarbonate. The mixture was kept at 70-75 °C for 1.5 h, cooled
the reaction mixture to room temperature, extracted with 35 ×
5 mL of ether, dried with magnesium sulfate. The magnesium
sulfate was filtered and the solvent was removed under reduced
pressure and 0.16 g brown solid 1-amino-3,4-dinitropyrazole
(ADNP) was obtained with a yield of 14.6 %. 1H NMR(DMSO-
d6, 500 MHz), δ: 6.110 (s, 2H, NH2), 7.768 (s, 1H, CH); 13C
NMR (DMSO-d6, 125 MHz), δ: 115.97, 131.26, 144.81; IR
(KBr, νmax, cm-1), 3498, 3452, 3368 (-NH2), 3239 (=CH), 1546,
1322 (-NO2); Anal. calcd. for C3H3N5O4: C 20.82, N 40.46, H
1.75; found C 20.37, N 39.26, H 1.92; MS (m/z): 173 [M+].
Synthesis ofADNPP and DADNP: 1-Amino-3,6-dinitro-
pyrazolo[4,3-c]pyrazole(ADNPP) and 1,4-diamino-3,6-dinitro-
pyrazolo[4,3-c] pyrazole (DADNP) were synthesized by the
method outlined in Scheme-III.
Synthesis ofADFP and DADFP: 4-Aminodifurazano[3,4-
b,e]pyrazine (ADFP) and 4,8-diaminodifurazano[3,4-
b,e]pyrazine (DADFP) were synthesized by the method out-
lined in Scheme-IV.
To a solution of 0.5 g (0.003 mol) of 4,8-dihydro-
difurazano[3,4-b,e]pyrazine (DFP) and 0.75 g (0.007 mol) of
sodium carbonate in 14.5 mL of water at 70-75 °C, we added
a solution of 1.02 g (0.008 mol) of hydroxylamino-O-sulfuric
acid in 5.2 mL of water for 10 min. The pH was kept at 8-9 by
the addition of sodium bicarbonate. The mixture was kept at
70-75 °C for 1.5 h and was then cooled to 15-20 °C. The preci-
pitate was filtered off, washed with water and acetone and
dried to give 0.04 g offwhite solid 4,8-diamino-difurazano[3,4-
The concentrated nitric acid (1100 mL) was transferred
into a three-necked round bottom flask fitted with a mechanical
stirrer, then 6-dinitropyrazolo[4,3-c]pyrazole-3-carboxylic
acid (CNPP) (190 g , 0.96 mo1) was added by portion wise
addition under the cold water condition. The reaction mixture
was heated up to 45 °C and stirred for another 6 h. The reaction
NO2
COOH
H2N
NO2
NO2
H
N
H
N
H
N
N
H2NOSO3H
HNO3
N
N
N
N
N
+
N
N
N
N
H
N
H
N
N
NH2
NH2
O2N
O2N
O2N
O2N
ADNPP
DADNP
CNPP
DNPP
Scheme-III: Synthetic route for ADNPP and DADNP

7154 Li et al.
Asian J. Chem.
NH2
N
NH2
N
H
N
N
N
N
N
N
N
N
N
N
NH OSO H
2
3
O
O
+ O
O
O
O
N
N
N
N
N
H
N
H
NH2
DFP
ADFP
DADFP
Scheme-IV: Synthetic route for ADNPP and DADNP
b,e]pyrazine (DADFP) with a yield of 6.8 %. m.p.: 282.3-
Structural determination of DNT: Single crystals of
DNT suitable for X-ray diffraction studies were grown by
allowing water to slowly diffuse into a saturated solution of
DNT for ten days at room temperature.
1
283.8 °C. H NMR (DMSO-d6, 500 MHz), δ: 5.788 (s, 4H,
-2NH2); 13C NMR (DMSO-d6, 125 MHz), δ: 149.93; IR (KBr,
νmax, cm-1), 3312, 3246 (-NH2), 1666 (C=N), 1613, 1443, 1021
(furazan ring);Anal. calcd for C4H4N8O2: C 24.50, N 57.13, H
2.06; found (%): C 24.41, N 57.23, H 2.01; MS (m/z): 180
[M-NH2]-.
A yellow single crystal with dimensions of 0.20 × 0.18 ×
0.23 was chosen for X-ray diffraction analysis and the data
were collected on a Bruker SMART APEXII CCD X-ray
diffractometer with a MoKα radiation (λ = 0.71073 Å) by using
a φ-ω scan mode at 296(2) K. In the range of 2.82 ≤ θ ≤ 28.33°,
a total of 3144 reflections were collected including 1483 unique
ones (Rint = 0.0276), of which 1483 were observed with I >
2σ(I). The structure was solved by direct methods using
SHELXS program of the SHELXL-97 package and refined
with SHELXL package13,14. The final refinement was perfor-
med by full-matrix least-squares method with anisotropic
thermal parameters on F2 for the non-hydrogen atoms. The
hydrogen atoms were located from Fourier difference maps.
The final R = 0.0555, wR = 0.1772, S = 1.166, (∆ρ)max =
0.345 and (∆ρ)min =-0.397 e/Å3.
During the neutralization of the above alkaline filtrate
solution with hydrochloric acid, the monosubstitition product
of DFP was separated. It was washed with water and dried to
give 0.153 g white solid 4-aminodifurazano[3,4-b,e]pyrazine
(ADFP) with a yield of 28.1 %. m.p.: 217.8-219.4 °C. 1H NMR
(DMSO-d6, 500 MHz), δ: 5.751 (s, 2H, -NH2), 11.913 (s, 1H,
-NH);13C NMR (DMSO-d6, 125 MHz), δ: 146.89, 150.22; IR
(KBr, νmax, cm-1), 3325 (-NH2), 3283 (-NH), 1654 (C=N), 1618,
1445, 1003 (furazan ring);Anal. Calcd for C4H3N7O2: C 26.53,
N 54.14, H 1.67; found C 26.38, N 54.21, H 1.76; MS (m/z):
180 [M-H]-.
Structural determination of DAT: Single crystals of
DAT suitable for X-ray diffraction studies were grown by
allowing ethanol to slowly diffuse into a saturated solution of
DAT for five days at room temperature.
RESULTS AND DISCUSSION
Crystal structure of DAT: The selected bond lengths and
bond angles, selected torsion angles and hydrogen bonds are
given in Tables 1-3, respectively.A displacement ellipsoid plot
with atomic numbering scheme and a perspective view of the
crystal in a unit cell are shown in Figs. 1 and 2, respectively.
It can be seen from Fig. 1 that the molecular structure of
DAT is composed of one 1,2,4-triazole ring and two amino
groups to C(1) and C(2), respectively. Because of the Van Der
Waals repulsion between those substituents contacted to C(1)
and C(2), The torsion angles, which are N(4)-C(2)-N(3)-C(1)
(-175.19(9)), N(4)-C(2)-N(1)-N(2) (175.13(9)), N(5)-C(1)-
N(3)-C(2) (-176.20(10)), N(5)-C(1)-N(2)-N(1) (176.17(10)),
C(2)-N(1)-N(2)-C(1) (0.06(11)), N(1)-C(2)-N(3)-C(1)
(0.19(11)), in Table-2 indicate that all non-hydrogen atoms
are amost in one plane. Moreover, the final three-dimensional
networks (Fig. 2) are formed by classical intermolecular
A colorless single crystal with dimensions of 0.21 mm ×
0.23 mm × 0.15 mm was chosen for X-ray diffraction analysis
and the data were collected on a Bruker SMARTAPEXII CCD
X-ray diffractometer with a MoKα radiation (λ = 0.71073 Å)
by using a φ-ω scan mode at 296(2) K. In the range of 3.77 ≤
θ ≤ 28.37°, a total of 2513 reflections were collected including
1068 unique ones (Rint = 0.0236), of which 1068 were observed
with I > 2σ(I). The structure was solved by direct methods
using SHELXS program of the SHELXL-97 package and
refined with SHELXL package13,14. The final refinement was
performed by full-matrix least-squares method with anisotropic
thermal parameters on F2 for the non-hydrogen atoms. The
hydrogen atoms were located from Fourier difference maps.
The final R = 0.0354, wR = 0.0936, S = 1.005, (∆ρ)max =
0.163 and (∆ρ)min = -0.215 e/Å3.
TABLE-1
SELECTED BOND LENGTHS (Å) AND BOND ANGLES (°)
Bond
C(1)-N(2)
C(2)-N(1)
N(1)-N(2)
Angle
Dist.
Bond
C(1)-N(3)
C(2)-N(3)
Dist.
1.3350(13)
1.3581(13)
Bond
C(1)-N(5)
C(2)-N(4)
Dist.
1.3515(14)
1.3740(13)
1.3356(13)
1.3215(13)
1.3914(12)
(°)
Angle
(°)
Angle
(°)
N(2)-C(1)-N(3)
N(1)-C(2)-N(3)
C(2)-N(1)-N(2)
110.42(9)
115.66(9)
101.57(8)
N(2)-C(1)-N(5)
N(1)-C(2)-N(4)
C(1)-N(2)-N(1)
124.19(10)
123.00(9)
109.58(9)
N(3)-C(1)-N(5)
N(3)-C(2)-N(4)
C(1)-N(3)-C(2)
125.27(9)
121.17(9)
102.77(8)

Vol. 26, No. 21 (2014)
Synthesis and Structural Characterization of N-Amino Compounds 7155
TABLE-2
SELECTED TORSION ANGLES (º)
Angle
(°)
Angle
(°)
Angle
(°)
N(3)-C(2)-N(1)-N(2)
N(5)-C(1)-N(2)-N(1)
N(5)-C(1)-N(3)-C(2)
-0.16(11)
176.17(10)
-176.20(10)
N(4)-C(2)-N(1)-N(2)
C(2)-N(1)-N(2)-C(1)
N(1)-C(2)-N(3)-C(1)
175.13(9)
0.06(11)
0.19(11)
N(3)-C(1)-N(2)-N(1)
N(2)-C(1)-N(3)-C(2)
N(4)-C(2)-N(3)-C(1)
0.05(12)
-0.14(11)
-175.19(9)
TABLE-3
HYDROGEN BONDS
D-H...A
d(D-H)
d(H...A)
d(D...A)
< (DHA)º
156.7(13)
141.7(13)
153.1(14)
153.2(14)
169.0(15)
Symmetry code
-x, y + 1/2, -z + 3/2
x, -y-1/2, z + 1/2
-x, -y, -z + 2
x, -y + 1/2, z-1/2
-x + 1, -y, -z + 2
N(2)-H(1)...N(1)
N(4)-H(2)...N(5)
N(4)-H(3)...N(1)
N(5)-H(4)...N(4)
N(5)-H(5)...N(3)
0.850(16)
0.873(16)
0.872(18)
0.864(18)
0.903(19)
2.154(16)
2.489(16)
2.301(18)
2.347(18)
2.107(19)
2.9534(13)
3.2200(17)
3.1046(16)
3.1424(16)
2.9976(15)
hydrogen bonds N(2)-H(1)...N(1) (-x, y + 1/2, -z + 3/2), N(4)-
H(2)...N(5) (x, -y-1/2, z + 1/2), N(4)-H(3)...N(1) (-x, -y, -z +
2), N(5)-H(4)...N(4) (x, -y + 1/2, z-1/2), N(5)-H(5)...N(3)
(-x + 1, -y, -z + 2) (Table-3), which further stabilize the solid
structure of compound DAT.
Fig. 2. Packing structure of DAT in a unit cell
(x + 1, y, z), O(5)-H(1)...N(5) (x + 1, y, z), N(2)-H(3)...O(5)
(-x + 3/2, -y + 1, z + 1/2) hydrogen bonds between DNT and
water, which further stabilize the structure. The corresponding
lengths and angles of hydrogen bonds are listed in Table-6.
Fig. 1. Crystal structure of DAT
Crystal structure of DNT: The selected bond lengths
and bond angles, selected torsion angles and hydrogen bonds
are given in Tables 4-6, respectively. A displacement ellipsoid
plot with atomic numbering scheme and a perspective view of
the crystal in a unit cell are shown in Figs. 3 and 4, respectively.
It can be seen from Fig. 1 that the molecular structure of
DNT is composed of one 1,2,4-triazole ring and two nitro
groups to C(1) and C(2), respectively. Because of the van der
Waals repulsion between those substituents contacted to C(1)
and C(2), The torsion angles, which are O(2)-N(4)-C(1)-N(3)
(177.7(2)), N(1)-N(2)-C(1)-N(3) (-0.2(3)), N(2)-N(1)-C(2)-
N(5) (178.71(19)), O(4)-N(5)-C(2)-N(1) (0.6(3)), N(1)-N(2)-
C(1)-N(4) (-179.3(2)), O(4)-N(5)-C(2)-N(3) (179.2(2)), O(2)-
N(4)-C(1)-N(2) (-3.3(3)), O(3)-N(5)-C(2)-N(3) (-1.7(4)), in
Table-5 indicate that all non-hydrogen atoms are amost in one
plane. In addition, there are intermolecular O(5)-H(1)...O(3)
Fig. 3. Crystal structure of DNT

7156 Li et al.
Asian J. Chem.
TABLE-4
SELECTED BOND LENGTHS (Å) AND BOND ANGLES (°)
Bond
Dist.
Bond
Dist.
Bond
Dist.
N(1)-C(2)
N(3)-C(2)
N(5)-O(3)
N(4)-O(2)
1.326(3)
1.317(4)
1.223(3)
1.231(3)
(°)
N(1)-N(2)
N(2)-C(1)
N(5)-C(2)
N(4)-C(1)
1.329(3)
1.335(3)
1.454(3)
1.428(4)
(°)
N(3)-C(2)
N(5)-O(4)
N(4)-O(1)
1.317(4)
1.208(3)
1.222(3)
Angle
Angle
Angle
(°)
C(2)-N(1)-N(2)
O(4)-N(5)-O(3)
O(1)-N(4)-O(2)
N(3)-C(1)-N(2)
N(3)-C(2)-N(1)
101.1(2)
124.5(2)
123.3(3)
112.3(2)
118.1(2)
C(2)-N(3)-C(1)
O(4)-N(5)-C(2)
O(1)-N(4)-C(1)
N(3)-C(1)-N(4)
N(3)-C(2)-N(5)
99.6(2)
117.9(2)
118.8(2)
126.0(2)
122.5(2)
N(1)-N(2)-C(1)
O(3)-N(5)-C(2)
O(2)-N(4)-C(1)
N(2)-C(1)-N(4)
N(1)-C(2)-N(5)
108.8(19)
117.6(2)
117.9(2)
121.7(2)
119.4(2)
TABLE-5
SELECTED TORSION ANGLES (º)
Angle
(°)
0.1(2)
-0.2(3)
177.7(2)
-0.1(3)
178.71(19)
0.6(3)
Angle
(°)
0.1(3)
-179.3(2)
177.6(2)
-178.8(2)
179.2(2)
179.6(2)
Angle
(°)
C(2)-N(1)-N(2)-C(1)
N(1)-N(2)-C(1)-N(3)
O(2)-N(4)-C(1)-N(3)
C(1)-N(3)-C(2)-N(1)
N(2)-N(1)-C(2)-N(5)
O(4)-N(5)-C(2)-N(1)
C(2)-N(3)-C(1)-N(2)
N(1)-N(2)-C(1)-N(4)
O(1)-N(4)-C(1)-N(2)
C(1)-N(3)-C(2)-N(5)
O(4)-N(5)-C(2)-N(3)
O(3)-N(5)-C(2)-N(1)
C(2)-N(3)-C(1)-N(4)
O(1)-N(4)-C(1)-N(3)
O(2)-N(4)-C(1)-N(2)
N(2)-N(1)-C(2)-N(3)
O(3)-N(5)-C(2)-N(3)
179.2(2)
-1.4(4)
-3.3(3)
0.0(3)
-1.7(4)
TABLE-6
HYDROGEN BONDS
D-H...A
d(D-H)
1.01(3)
1.01(3)
0.75(6)
d(H...A)
d(D...A)
3.042(3)
3.557(3)
2.685(3)
<(DHA)º
169(3)
144(3)
145(6)
Symmetry code
x + 1, y, z
x + 1, y, z
O(5)-H(1)...O(3)
O(5)-H(1)...N(5)
N(2)-H(3)...O(5)
2.04(3)
2.69(4)
2.03(6)
-x + 3/2, -y + 1, z + 1/2
Supplementary data: Crystallographic data for the struc-
tural analysis have been deposited in the Cambridge Data
Center (CCDC), CCDC number of 3,5-diamino-1,2,4-triazole
(DAT): 920604 for C2H5 N5, CCDC number of 3,5-dinitro-
1,2,4-triazole (DNT·H2O): 920605 for C2H3N5O5.
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Fig. 4. Packing structure of DNT in a unit cell
Conclusion
In summary, seven N-amino compounds were synthesized
using imino compounds as start materials and hydroxylamino-
O-sulfuric acid as amination reagent by N-amination reaction.
The structures of target compounds and intermediates were
characterized. Two single crystals of 3,5-diamino-1,2,4-triazole
(DAT) and 3,5-dinitro-1,2,4-triazole (DNT·H2O) were grown
and their crystal structure were characterized by single-crystal
X-ray diffraction analysis.
14. G.M. Sheldrick, SHELXL-97, Program for Crystal Structure Refinement,
University of Göttingen, Germany (1997).