1,3-bis(4-nitrophenyl)triazene

Article abstract of DOI:10.1107/S0108270103012125

The structure of the title compound, C₁₂H₉N ₅O₄ reveals an almost planar molecule (r.m.s. deviation = 0.061 A), in which the interplanar angle between the phenyl rings is 5.7 (1)° and the largest interplanar angle is that between the phenyl ring and the nitro group of one of the 4-nitrophenyl substituents [8.8 (3)°]. The observed molecular conformation suggests a delocalization of π-electrons extended over the diazoamine group and the terminal aryl substituents. Intermolecular N-H...O interactions between the twofold screw-related molecules give rise to helical chains along the [010] direction. Intermolecular C-H...O interactions then generate sheets of molecules in the (101) plane, and these sheets are held together by N...C and O...O π-π interactions.

Full text of DOI:10.1107/S0108270103012125

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
from typical NÐN and C ÐN bond lengths suggest that the
ar
delocalization of the ꢀ-electrons on the triazene group has
extended to the terminal 4-nitrophenyl substituents. The
ISSN 0108-2701
Ê
N12 N13 bond [1.263 (2) A] is longer than the characteristic
Ê
value for a double bond (1.24 A), whereas the N11ÐN12 bond
Ê
1.340 (2) A] is shorter than the characteristic value for a
[
single bond (1.44 A; International Tables for X-ray Crystal-
1
,3-Bis(4-nitrophenyl)triazene
Ê
Ê
lography, 1985, Vol. III, p. 270). The N11ÐC11 [1.383 (2) A]
Ê
and N13ÐC21 [1.430 (2) A] bonds are shorter than the length
a
a
a
Manfredo H oÈ rner, * Leandro Bresolin, Jairo Bordinhao,
Edmund Hartmann and Joachim Str aÈ hle
b
b
expected for a C ÐN single bond and are in good agreement
ar
with the distances found in the related compound
1,3-bis(3-nitrophenyl)triazene [N4 N3 = 1.261 (2) AÊ , N2Ð
a
Departamento de Quimica, Universidade Federal de Santa Maria, Caixa Postal
b
5
071, 97110-900 Santa Maria, RS, Brazil, and Institut f uÈ r Anorganische Chemie,
Ê
N3 = 1.326 (2) A, N2ÐC5 = 1.393 (2) A and N4ÐC11 =
Ê
Universit aÈ t T uÈ bingen, Auf der Morgenstelle 18, D-72076 T uÈ bingen, Germany
Correspondence e-mail: hoerner@base.ufsm.br
Ê
.426 (2) A; Zhang et al., 1999].
The crystal structure contains molecules related by a
1
Received 12 May 2003
Accepted 2 June 2003
Online 12 July 2003
twofold screw axis, which form helical chains along the [010]
direction via NÐHÁ Á ÁO hydrogen bonds (Table 2). These
chains are linked by CÐHÁ Á ÁO intermolecular interactions
The structure of the title compound, C H N O , reveals an
1
2
9
5
4
Ê
almost planar molecule (r.m.s. deviation = 0.061 A), in which
ꢀ
the interplanar angle between the phenyl rings is 5.7 (1) and
the largest interplanar angle is that between the phenyl ring
and the nitro group of one of the 4-nitrophenyl substituents
ꢀ
[8.8 (3) ]. The observed molecular conformation suggests a
delocalization of ꢀ-electrons extended over the diazoamine
group and the terminal aryl substituents. Intermolecular NÐ
HÁ Á ÁO interactions between the twofold screw-related mol-
ecules give rise to helical chains along the [010] direction.
Intermolecular CÐHÁ Á ÁO interactions then generate sheets of
molecules in the (101) plane, and these sheets are held
together by NÁ Á ÁC and OÁ Á ÁO ꢀ±ꢀ interactions.
Figure 1
The molecular structure of (I), with displacement ellipsoids for non-H
atoms drawn at the 50% probability level. H atoms are shown as small
spheres of arbitrary radii.
Comment
Numerous examples of free 1,3-disubstituted triazenes,
RN NÐN(H)R, characterized by X-ray diffraction studies
con®rm a trans stereochemistry about the N N double bond
(
Moore & Robinson, 1986). During the past few decades,
asymmetric alkyl/aryl-substituted triazenes have been inves-
tigated for their biological activity. The resonance effect in the
diazoamine group has been related to the antitumour activity
of some triazene derivatives (Zhang et al., 1999). On the other
hand, studies of molecules with DNA binding af®nity indicate
that the planarity has a marked effect on the insertion
between the base pairs (Mahadevan & Palaniandavar, 1998;
Zhen et al., 1999, 2000). We report here the synthesis and
structural characterization of the title compound, (I), a
symmetric disubstituted 1,3-diaryltriazene that has ꢀ acid
nitro groups on the para-substituted terminal aryl (ar) rings.
The molecular structure of (I) is shown in Fig. 1 and
selected geometric parameters are given in Table 1. Deviations
Figure 2
A view of a sheet of molecules of (I), showing the NÐHÁ Á ÁO and CÐ
HÁ Á ÁO interactions. Atoms marked with an `at' sign (@), a dollar sign ($)
1
2
3
2
or a hash (#) are at the symmetry positions (1 � x, + y, � z), (� x,
1
1
1
2
3
2
� + y, � z) and (1 � x, � + y, � z), respectively.
2
2
o426 # 2003 International Union of Crystallography
DOI: 10.1107/S0108270103012125
Acta Cryst. (2003). C59, o426±o427

organic compounds
(Table 2), generating sheets in the (101) plane (Fig. 2), and
these sheets are then linked into a three-dimensional mol-
Table 1
Selected geometric parameters (A, ).
Ê
ꢀ
ecular array by NÁ Á ÁC and OÁ Á ÁO ꢀ±ꢀ interactions
O12ÐN1
O11ÐN1
O22ÐN2
O21ÐN2
1.221 (2)
1.215 (2)
1.216 (3)
1.217 (2)
N11ÐN12
N11ÐC11
N12ÐN13
N13ÐC21
1.340 (2)
1.383 (2)
1.263 (2)
1.430 (2)
iv
v
Ê
Ê
[
N11Á Á ÁC21 = 3.388 (3) A and O21Á Á ÁO21 = 3.117 (4) A;
3 1
symmetry codes: (iv) x, � y + , z + ; (v) � x, � y + 2, � z].
2
2
These values are in good agreement with the ꢀ±ꢀ contacts
Ê
found in 1,3-bis(3-nitrophenyl)triazene [NÁ Á ÁC = 3.387 (3) A
N12ÐN11ÐC11
N13ÐN12ÐN11
120.09 (16)
112.32 (15)
N12ÐN13ÐC21
112.14 (15)
Ê
and OÁ Á ÁO = 3.182 (3) A; Zhang et al., 1999].
Because of the strong ꢀ acidity of the nitro groups, which
favours the delocalization of the ꢀ-electrons and the conju-
gation between the C11±C16 and C21±C26 phenyl rings and
Table 2
Hydrogen-bonding geometry (A, ).
Ê
ꢀ
the N NÐN(H) moiety, the whole molecule is almost planar
ꢀ
[interplanar
O21ÐN2ÐO22/C21±C26 = 8.8 (3) , C11±C16/H11ÐN11Ð
angles
O11ÐN1ÐO12/C11±C16 = 7.3 (1) ,
ꢀ
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
i
ꢀ
N11ÐH11Á Á ÁO12
0.86
0.93
0.93
0.93
2.11
2.49
2.50
2.46
2.929 (2)
3.248 (3)
3.194 (3)
3.222 (3)
159
139
131
140
N12ÐN13 = 6.4 (1) and C21±C22/N13ÐN12ÐN11ÐH11 =
ii
i
C12ÐH12Á Á ÁO12
C16ÐH16Á Á ÁO21
C25ÐH25Á Á ÁO11
ꢀ
3
[
.7 (1) ]. The weak intermolecular C16Á Á ÁO21 contact
ii
iii
Ê
3.194 (3) A; see Table 2 for symmetry code] causes the C11±
ꢀ
C16 phenyl ring to deviate by an angle of 6.4 (1) from the
plane de®ned by the N13 N12ÐN11ÐH11 moiety, while the
C21±C26 phenyl ring remains nearly coplanar with the
diazoamine group.
1
2
3
2
1 1
Symmetry codes: (i) 1 � x; ‡ y; � z; (ii) � x; y �
;
2 2
� z; (iii) x; 1 ‡ y; z.
The H-atom positional parameters were obtained geometrically
Ê
Ê
(
CÐH = 0.93 A and NÐH = 0.86 A) and re®ned as riding on the
respective C and N atoms, with Uiso values of 1.2 times the Ueq values
2
2
of the attached Csp and Nsp atoms. The nitro atoms show a large
thermal motion, as indicated by their elongated displacement ellip-
soids (Fig. 1). Split peaks for these atoms were not observed and
consequently a disorder model was not used.
Experimental
4-Nitroaniline (21.5 g, 155 mmol) was dissolved in glacial acetic acid
(40 ml) and cooled to below room temperature. A sodium nitrite
solution (5.4 g, 78 mmol) in water (100 ml) was added slowly with
continuous stirring. The yellow reaction mixture was then neutralized
Data collection: CAD-4 EXPRESS (Enraf±Nonius, 1994); cell
re®nement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms &
Wocadlo, 1995); program(s) used to solve structure: SHELXS97
with an aqueous solution (10%) of NaHCO
was observed. The crude yellow product was isolated by ®ltration and
dried over P in a vacuum and the product was recrystallized from
3
and a yellow precipitate
(Sheldrick, 1997); program(s) used to re®ne structure: SHELXL97
(Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows
(Farrugia, 1997) and PLATON (Spek, 2003); software used to
2
O
5
a tetrahydrofuran/n-hexane mixture (1:1). Yellow column-shaped
crystals suitable for X-ray analysis were obtained by slow evaporation
of the solvent mixture (yield 15.1 g, 67.5%; m.p. 506 K).
prepare material for publication: WinGX (Farrugia, 1999).
This work has received partial support from CNPq (grant
No. 475734/01±7) and FAPERGS. MH, JB and LB thank
CNPq for grants. The authors thank Professor Dr A. Neves
and Professor Dr I. Vencato, Universidade Federal de Santa
Catarina, Brazil, for providing diffractometer facilities.
Crystal data
�
3
C
12
9
H N
O
5 4
D
x
= 1.478 Mg m
r
M = 287.24
Monoclinic, P2 =c
Mo Kꢂ radiation
Cell parameters from 25
re¯ections
1
Ê
a = 13.452 (1) A
Ê
b = 13.671 (2) A
ꢀ
ꢃ = 2.1±25.4
ꢄ = 0.12 mm
T = 293 (2) K
Ê
c = 7.034 (2) A
� 1
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: FG1694). Services for accessing these data are
described at the back of the journal.
ꢀ
Ê
ꢁ
= 93.442 (11)
3
V = 1291.2 (4) A
Z = 4
Column, yellow
0.30 Â 0.20 Â 0.10 mm
Data collection
References
ꢀ
Enraf±Nonius CAD-4
diffractometer
ꢃ/2ꢃ scans
ꢃmax = 25.4
Enraf±Nonius (1994). CAD-4 EXPRESS. Version 5.1/1.2. Enraf±Nonius,
Delft, The Netherlands.
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.
h = � 16 ! 16
k = 0 ! 16
2
2
1
581 measured re¯ections
375 independent re¯ections
405 re¯ections with I > 2ꢅ(I)
l = 0 ! 8
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837±838.
3 standard re¯ections
frequency: 60 min
intensity decay: 1%
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.
Mahadevan, S. & Palaniandavar, M. (1998). Inorg. Chem. 37, 693±700.
Moore, D. S. & Robinson, S. D. (1986). Adv. Inorg. Chem. Radiochem. 30, 1±
Rint = 0.017
68.
Re®nement
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of
G oÈ ttingen, Germany.
Spek, A. L. (2003). J. Appl. Cryst. 36, 7±13.
Zhang, D.-C., Fei, Z.-H., Zhang, T.-Z., Zhang, Y.-Q. & Yu, K.-B. (1999). Acta
Cryst. C55, 102±104.
Zhen, Q.-X., Ye, B.-H., Zhang, Q.-L., Liu, J.-G., Li, H., Ji, L.-N. & Wang, L.
(1999). J. Inorg. Biochem. 76, 47±53.
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Inorg. Biochem. 78, 293±298.
2
2
2
2
Re®nement on F
R(F) = 0.038
w = 1/[ꢅ (F ) + (0.0647P)
o
+ 0.0938P]
where P = (Fo + 2F )/3
(Á/ꢅ)max = 0
2
wR(F ) = 0.124
S = 0.98
2
2
c
Ê
� 3
2
1
375 re¯ections
91 parameters
Áꢆmax = 0.18 e A
Ê
� 3
Áꢆmin = � 0.16 e A
H-atom parameters constrained
Extinction correction: SHELXL97
Extinction coef®cient: 0.015 (2)
ꢁ
Acta Cryst. (2003). C59, o426±o427
Manfredo H oÈ rner et al.
C H
12 9
N O
5 4
o427