2,2-Dimethyl-1-(2,4,6-trinitrophenyl)-hydrazine

Full text of DOI:10.1107/S0108270199014547

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
ISSN 0108-2701
2,2-Dimethyl-1-(2,4,6-trinitrophenyl)-
hydrazine
J. Wilson Quail,* John A. Weil and Malvinder P. Singh
Department of Chemistry, University of Saskatchewan, 110 Science Place,
Saskatoon, Saskatchewan, Canada S7N 5C9
Correspondence e-mail: wilson.quail@usask.ca
Received 22 July 1999
Accepted 8 November 1999
Figure 1
The title molecule (DMPH-H), C8H9N5O6, was investigated to
provide comparison with 2,2-diphenyl-1-picrylhydrazine,
which unlike DMPH-H is readily oxidizable to form a well
known stable free radical (DPPH). The structure shows
essential differences in the con®guration of the hydrazine-N
atoms, the ortho-nitro group orientations and the crystal
packing. The bond angles of the dimethylamino N atom
[107.90 (13), 108.96 (12) and 112.21 (13)ꢀ] are consistent with
a tetrahedral N atom and sp3 hybridization.
A general ORTEPII (Johnson, 1976) view of the title compound with
non-hydrogen displacement ellipsoids drawn at the 50% probability level.
For clarity, the H atoms are drawn as small spheres of arbitrary size.
differences (e.g. of the ꢀ-electron systems) elucidate the
chemical differences.
The structure of DMPH-H has an intramolecular hydrogen
bond between the H atom on N1 and one of the O atoms on
N2 (O21) [or N6 (O61)] to form a six-membered ring (Fig. 1),
a structure found in all of the picryl hydrazines (Brown et al.,
1999; Wang et al., 1991). The result is to put the plane of the N2
nitro group fairly close [22.62 (6)ꢀ] to the plane of the picryl
ring {whereas the plane of the N6 nitro group adopts a
conformation highly twisted [52.74 (6)ꢀ] relative to the plane
of the picryl ring due to the proximity of atom N7} unlike the
coplanar situation in DPPH-H (Wang et al., 1991).
Comment
2,2-Dimethyl-1-picrylhydrazine (DMPH-H) reported herein is
the latest member of a series of closely related picryl-
hydrazines being investigated in an ongoing study of their
internal rotations (conformerizations), as well as the acidity
and oxidizability of the hydrazinic moiety (e.g. Brown et al.,
1999; Tyson & Weil, 1990). Comparisons of the molecular
structures, pseudo-thermodynamic conformerization activa-
tion parameters, chemical properties, and the results of
molecular-orbital computations have been a vital component
of this work (Brown et al., 1999; Wang et al., 1991).
There are no solvent molecules trapped in the DMPH-H
structure and no large cavities in the lattice, unlike DPPH-H
which crystallizes with interstitial clathrate solvent molecules
(Wang et al., 1991).
Atom H1 forms a short intramolecular hydrogen bond with
an ortho nitro group (as in DPPH-H) but also forms a long
intermolecular hydrogen bond to atom O22 on an adjacent
molecule (12 + x,
y, 1 z) (unlike in DPPH-H).
1
2
Dynamic NMR and self-consistent-®eld molecular-orbital
studies of DMPH-H are under way.
Experimental
A mixture of picryl chloride (2.48 g, 10 mmol) and K2CO3 (1.65 g,
12 mmol) was dissolved in 1:1 MeOH±H2O (50 ml). To this solution,
cooled to 273 K, was added dropwise a solution of 1,1-dimethyl-
hydrazine (720 mg, 12 mmol) dissolved in MeOH (5 ml). After the
addition was complete, the resulting deep-red-colored solution was
stirred for 1 h. The reaction mixture was evaporated to the point of
turbidity, warmed gently to afford a homogeneous solution and
allowed to cool down slowly to afford a yellow solid. Filtration and
recrystallization from absolute EtOH gave 2.2 g (82% yield) of the
title compound [m.p. 411±413 K (literature 409±411 K; Latham et al.,
1976)]; IR (KBr) ꢁmax: 3270 (m, NÐH str), 3093 (m, CÐH str), 1620
(s), 1590 (m), 1512 (s), 1456 (m), 1333 (s), 1301 (m), 1087 (m),
DMPH-H was reported earlier as not being oxidizable to
the corresponding hydrazyl radical (Poirier & Benington,
1954). We have con®rmed this observation, of interest since
2,2-diphenyl-1-picrylhydrazine (DPPH-H) forms a very stable
free radical (DPPH). The bond angles for N7 of DMPH-H
[107.90 (13), 108.96 (12) and 112.21 (13)ꢀ] are consistent with
a tetrahedral N atom and sp3 hybridization, compared to the
equivalent N atom in DPPH-H which is sp2 hybridized (with
some sp3 character) (Wang et al., 1991). Thus, the structural
ꢁ
Acta Cryst. (2000). C56, 235±236
Quail, Weil and Singh C8H9N5O6 235

organic compounds
724 (m) cm 1; 1H NMR (300 MHz, CDCl3, p.p.m.) ꢂ: 2.59 (s, 6H), 8.30
(bs, 1H), 8.98 (s, exch, 1H), 9.16 (bs, 1H); 1H NMR (300 MHz,
Table 1
Hydrogen-bonding geometry (A, ).
ꢀ
Ê
DMSO-d6, p.p.m.) ꢂ: 2.57 (s, 6H), 8.81 (s, 2H), 9.73 (s, exch, 1H); 13
C
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
NMR [75 MHz, (CD3)2CO, p.p.m.] ꢂ: 45.3 (q, CH3), 123.9 (s, Ar±C),
124.8 (s, Ar±C), 133.8 (d, Ar±CH), 141.1 (d, Ar±CH); EI±MS m/z
(relative intensity): calculated for C8H9N5O6 271.0553; found
271.0550 (M+, 37), 254.0529 (100), 209 (15), 179 (11), 149 (17).
Note: In an alternative preparation, using a reported method
(Nelsen & Weisman, 1973) based on reductive alkylation of hydra-
zines, a mixture of picryl hydrazine (2.43 g, 10 mmol), aqueous
HCHO (37%, 8 ml), and NaBH3CN (230 mg, 4 mmol) in 50 ml
MeOH was stirred at ambient temperature for 2 h. Usual workup, e.g.
extraction with EtOAc, washing with 10% NaHCO3 and water, and
evaporation of the organic extracts gave a yellow solid that was
puri®ed by crystallization (EtOH) to afford 1.6 g (58% yield) of the
title compound with physical and spectroscopic characteristics
essentially identical to the ones reported above.
N1ÐH1Á Á ÁO21
0.88
0.88
2.11
2.60
2.6666 (18)
3.358 (2)
120.1
144.6
N1ÐH1Á Á ÁO22i
1
Symmetry code: (i) ‡ x; 12 y; 1 z.
2
absence of any atom with more electrons than oxygen, it is not
possible to determine with certainty if the crystal used is all of one
hand or is a racemic twin. During re®nement, the structure was
treated as a racemic twin.
Data collection: CAD-4 EXPRESS (Enraf±Nonius, 1992); cell
re®nement: CAD-4 EXPRESS; data reduction: DIFDAT, SORTRF
and ADDREF in Xtal (Hall et al., 1997); program(s) used to solve
structure: Xtal; program(s) used to re®ne structure: SHELXL97
(Sheldrick, 1997); molecular graphics: Xtal; software used to prepare
material for publication: SHELXL97.
Crystal data
C8H9N5O6
Mr = 271.20
Orthorhombic, P212121
Mo Kꢃ radiation
Cell parameters from 25
re¯ections
The authors thank the Natural Sciences and Engineering
Research Council of Canada for operating grants to all and
funds for an X-ray diffractometer to JWQ.
ꢄ = 10.40±18.54ꢀ
Ê
a = 6.5156 (7) A
1
Ê
b = 8.2006 (11) A
ꢅ = 0.141 mm
T = 123 (2) K
Ê
3
c = 20.6704 (14) A
Ê
V = 1104.5 (2) A
Prism, orange
0.42 Â 0.30 Â 0.25 mm
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: DA1101). Services for accessing these data are
described at the back of the journal.
Z = 4
Dx = 1.631 Mg m
3
Data collection
Nonius CAD-4 diffractometer
! scans
Rint = 0.044
max = 33.48ꢀ
ꢄ
Absorption correction: scan
(North et al., 1968)
Tmin = 0.88, Tmax = 0.96
2553 measured re¯ections
2479 independent re¯ections
2171 re¯ections with I > 2ꢆ(I)
h = 0 ! 10
References
k = 0 ! 12
l = 0 ! 32
Brown, K., Weil, J. A., Robertson, B. E., Quail, J. W. & Zimpel, Z. (1999). Can.
J. Chem. 77, 1295±1304.
Enraf±Nonius (1992). CAD-4 EXPRESS. Version 1.1. Enraf±Nonius, Delft,
The Netherlands.
3 standard re¯ections
every 200 re¯ections
intensity decay: none
Hall, S. R., King, G. S. D. & Stewart, J. M. (1997). The Xtal System. University
of Western Australia, Australia.
Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National
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North, A. C. T., Phillips, D. C. & Mathews, F. C. (1968). Acta Cryst. A24, 351±
359.
Re®nement
Re®nement on F2
R[F2 > 2ꢆ(F2)] = 0.038
wR(F2) = 0.100
S = 1.046
2479 re¯ections
175 parameters
H atoms constrained
w = 1/[ꢆ2(Fo2) + (0.0563P)2
+ 0.2264P]
where P = (Fo2 + 2Fc2)/3
(Á/ꢆ)max < 0.001
3
Ê
Áꢇmax = 0.43 e A
3
Ê
0.35 e A
Áꢇmin
=
Poirier, R. H. & Benington, F. (1954). J. Org. Chem. 19, 1157±1161.
Sheldrick, G. M. (1997). SHELXL97. Program for the Re®nement of Crystal
The molecule is achiral but crystallizes in the non-centrosymmetric
space group P212121. The intermolecular hydrogen bonding described
in Table 1 produces continuous spirals of molecules, resulting in the
non-centrosymmetric space group. Using Mo radiation, and in the
È
Structures. University of Gottingen, Germany.
Tyson, R. L. & Weil, J. A. (1990). J. Phys. Chem. 94, 3951±3958.
Wang, H., Barton, R. J., Robertson, B. E. & Weil, J. A. (1991). J. Incl. Phenom.
Mol. Recognit. Chem. 10, 203±217.
ꢁ
236 Quail, Weil and Singh C8H9N5O6
Acta Cryst. (2000). C56, 235±236