3,5-Dimethyl-4-nitroso-1H-pyrazole.

In the unit cell of the title compound, C(5)H(7)N(3)O, there are two conformers (A and B) which differ in the position of the oxime group with respect to the protonated pyrazole nitro-gen (trans in the A conformer and cis in the B conformer) and in the geometric parameters. The oxime group exists in the nitroso form in both conformers. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O and N-H⋯N hydrogen bonds into zigzag-like chains along the b axis.

Related literature

For the use of pyrazole-based ligands, see: Mullins & Pecoraro (2008 ▶); Mukhopadhyay et al. (2004 ▶). For the magnetic properties of pyrazolate complexes, see: Aromi & Brechin (2006 ▶); Gatteschi et al. (2006 ▶). For the use of oxime substituents in the synthesis of polynuclear ligands, see: Petrusenko et al. (1997 ▶); Kanderal et al. (2005 ▶); Sachse et al. (2008 ▶); Moroz et al. (2010 ▶). For the use of 4-nitro­pyrazoles as ligands, see: Halcrow (2005 ▶). For related structures, see: Fletcher et al. (1997 ▶); Kovbasyuk et al. (2004 ▶); Mokhir et al. (2002 ▶); Sliva et al. (1997 ▶); Wörl, Fritsky et al. (2005 ▶); Wörl, Pritzkow et al. (2005 ▶). For the synthesis of the title compound, see: Cameron et al. (1996 ▶).

Experimental

Crystal data

C5H7N3O

M = 125.14

Monoclinic,

a = 4.0268 (2) Å

b = 15.3793 (7) Å

c = 19.6627 (9) Å

β = 94.613 (3)°

V = 1213.75 (10) Å3

Z = 8

Mo Kα radiation

μ = 0.10 mm−1

T = 120 K

0.46 × 0.33 × 0.13 mm

Data collection

Nonius KappaCCD diffractometer

Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997 ▶) T min = 0.955, T max = 0.987

9003 measured reflections

2747 independent reflections

1866 reflections with I > 2σ(I)

R int = 0.040

Refinement

R[F 2 > 2σ(F 2)] = 0.041

wR(F 2) = 0.109

S = 1.03

2747 reflections

175 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.23 e Å−3

Δρmin = −0.25 e Å−3

Data collection: COLLECT (Nonius, 2000 ▶); cell refinement: DENZO/SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO/SCALEPACK; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2008 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811033794/jh2317sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811033794/jh2317Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536811033794/jh2317Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C5H7N3O	F(000) = 528
Mr = 125.14	Dx = 1.370 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4238 reflections
a = 4.0268 (2) Å	θ = 1.0–27.5°
b = 15.3793 (7) Å	µ = 0.10 mm−1
c = 19.6627 (9) Å	T = 120 K
β = 94.613 (3)°	Plate, blue
V = 1213.75 (10) Å3	0.46 × 0.33 × 0.13 mm
Z = 8

Nonius KappaCCD diffractometer	2747 independent reflections
Radiation source: fine-focus sealed tube	1866 reflections with I > 2σ(I)
horizontally mounted graphite crystal	Rint = 0.040
Detector resolution: 9 pixels mm-1	θmax = 27.4°, θmin = 2.5°
φ scans and ω scans with κ offset	h = −4→5
Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997)	k = −18→19
Tmin = 0.955, Tmax = 0.987	l = −25→25
9003 measured reflections

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.109	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ2(Fo2) + (0.0516P)2 + 0.0988P] where P = (Fo2 + 2Fc2)/3
2747 reflections	(Δ/σ)max < 0.001
175 parameters	Δρmax = 0.23 e Å−3
0 restraints	Δρmin = −0.25 e Å−3

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

	x	y	z	Uiso*/Ueq
O1A	−0.1796 (3)	0.16615 (7)	0.22546 (5)	0.0279 (3)
N1A	0.3665 (3)	−0.05073 (9)	0.32527 (7)	0.0241 (3)
N2A	0.4403 (3)	0.02548 (8)	0.36162 (6)	0.0243 (3)
N3A	−0.1316 (3)	0.08489 (8)	0.22016 (7)	0.0240 (3)
C1A	0.2710 (3)	0.08712 (10)	0.32773 (8)	0.0210 (4)
C2A	0.2872 (4)	0.17879 (10)	0.35059 (8)	0.0258 (4)
H2A	0.4408	0.1837	0.3917	0.039*
H2B	0.0648	0.1981	0.3609	0.039*
H2C	0.3667	0.2152	0.3144	0.039*
C3A	0.0867 (4)	0.05016 (9)	0.26876 (8)	0.0202 (4)
C4A	0.1598 (4)	−0.03950 (10)	0.27044 (8)	0.0225 (4)
C5A	0.0466 (4)	−0.11093 (10)	0.22306 (9)	0.0308 (4)
H5A	0.1902	−0.1133	0.1852	0.046*
H5B	−0.1839	−0.1001	0.2052	0.046*
H5C	0.0589	−0.1664	0.2476	0.046*
O1B	−0.2132 (3)	0.13230 (7)	−0.04852 (6)	0.0356 (3)
N1B	0.3699 (3)	0.21423 (8)	0.11942 (7)	0.0216 (3)
N2B	0.3158 (3)	0.30207 (8)	0.10938 (7)	0.0226 (3)
N3B	−0.1646 (3)	0.20960 (9)	−0.03253 (7)	0.0275 (3)
C1B	0.1150 (4)	0.30759 (10)	0.05258 (8)	0.0214 (4)
C2B	0.0044 (4)	0.39331 (10)	0.02337 (8)	0.0267 (4)
H2B1	0.0884	0.4400	0.0540	0.040*
H2B2	−0.2395	0.3953	0.0182	0.040*
H2B3	0.0918	0.4009	−0.0213	0.040*
C3B	0.0397 (4)	0.22318 (10)	0.02693 (7)	0.0201 (3)
C4B	0.2123 (4)	0.16456 (10)	0.07173 (8)	0.0208 (4)
C5B	0.2411 (4)	0.06867 (10)	0.07173 (8)	0.0264 (4)
H5B1	0.3957	0.0502	0.1100	0.040*
H5B2	0.3250	0.0494	0.0288	0.040*
H5B3	0.0216	0.0428	0.0763	0.040*
H1A	0.453 (4)	−0.1013 (13)	0.3437 (9)	0.040 (5)*
H1B	0.515 (4)	0.1949 (11)	0.1572 (9)	0.035 (5)*

	U11	U22	U33	U12	U13	U23
O1A	0.0312 (6)	0.0231 (6)	0.0288 (7)	0.0049 (5)	−0.0017 (5)	0.0031 (5)
N1A	0.0283 (7)	0.0183 (7)	0.0252 (8)	0.0026 (6)	−0.0006 (6)	0.0023 (6)
N2A	0.0268 (7)	0.0221 (8)	0.0236 (7)	0.0000 (6)	0.0000 (6)	0.0000 (6)
N3A	0.0240 (7)	0.0244 (8)	0.0236 (7)	0.0010 (6)	0.0024 (6)	0.0034 (6)
C1A	0.0187 (8)	0.0230 (9)	0.0216 (8)	0.0002 (6)	0.0028 (6)	0.0019 (6)
C2A	0.0259 (8)	0.0246 (9)	0.0261 (9)	0.0004 (7)	−0.0024 (7)	−0.0031 (7)
C3A	0.0198 (8)	0.0204 (8)	0.0205 (8)	−0.0002 (6)	0.0023 (6)	0.0010 (6)
C4A	0.0224 (8)	0.0218 (9)	0.0235 (9)	−0.0005 (7)	0.0039 (7)	0.0021 (6)
C5A	0.0352 (9)	0.0228 (9)	0.0337 (10)	−0.0011 (7)	−0.0005 (8)	−0.0046 (7)
O1B	0.0459 (7)	0.0269 (7)	0.0328 (7)	−0.0057 (6)	−0.0044 (6)	−0.0041 (5)
N1B	0.0249 (7)	0.0172 (7)	0.0222 (7)	0.0014 (6)	−0.0014 (6)	0.0019 (5)
N2B	0.0270 (7)	0.0153 (7)	0.0250 (7)	0.0008 (5)	−0.0008 (6)	0.0011 (5)
N3B	0.0295 (7)	0.0247 (8)	0.0280 (8)	−0.0038 (6)	0.0007 (6)	−0.0014 (6)
C1B	0.0220 (8)	0.0203 (8)	0.0223 (8)	0.0005 (6)	0.0037 (7)	0.0001 (6)
C2B	0.0308 (9)	0.0205 (8)	0.0282 (9)	0.0013 (7)	−0.0010 (7)	0.0030 (7)
C3B	0.0212 (8)	0.0194 (8)	0.0198 (8)	−0.0005 (6)	0.0020 (6)	0.0002 (6)
C4B	0.0204 (8)	0.0211 (8)	0.0214 (8)	−0.0018 (6)	0.0041 (7)	−0.0013 (6)
C5B	0.0313 (9)	0.0184 (8)	0.0294 (9)	0.0012 (7)	0.0017 (7)	−0.0003 (7)

O1A—N3A	1.2701 (16)	O1B—N3B	1.2412 (16)
N1A—C4A	1.319 (2)	N1B—C4B	1.330 (2)
N1A—N2A	1.3922 (18)	N1B—N2B	1.3801 (17)
N1A—H1A	0.915 (19)	N1B—H1B	0.954 (18)
N2A—C1A	1.3170 (19)	N2B—C1B	1.3279 (19)
N3A—C3A	1.3553 (19)	N3B—C3B	1.3902 (19)
C1A—C3A	1.442 (2)	C1B—C3B	1.417 (2)
C1A—C2A	1.479 (2)	C1B—C2B	1.492 (2)
C2A—H2A	0.9800	C2B—H2B1	0.9800
C2A—H2B	0.9800	C2B—H2B2	0.9800
C2A—H2C	0.9800	C2B—H2B3	0.9800
C3A—C4A	1.410 (2)	C3B—C4B	1.405 (2)
C4A—C5A	1.488 (2)	C4B—C5B	1.479 (2)
C5A—H5A	0.9800	C5B—H5B1	0.9800
C5A—H5B	0.9800	C5B—H5B2	0.9800
C5A—H5C	0.9800	C5B—H5B3	0.9800
C4A—N1A—N2A	113.82 (13)	C4B—N1B—N2B	113.61 (12)
C4A—N1A—H1A	129.1 (11)	C4B—N1B—H1B	126.7 (10)
N2A—N1A—H1A	116.9 (11)	N2B—N1B—H1B	119.7 (10)
C1A—N2A—N1A	105.42 (12)	C1B—N2B—N1B	105.14 (12)
O1A—N3A—C3A	115.11 (12)	O1B—N3B—C3B	115.32 (13)
N2A—C1A—C3A	109.56 (13)	N2B—C1B—C3B	109.83 (13)
N2A—C1A—C2A	121.60 (13)	N2B—C1B—C2B	121.54 (13)
C3A—C1A—C2A	128.84 (13)	C3B—C1B—C2B	128.62 (14)
C1A—C2A—H2A	109.5	C1B—C2B—H2B1	109.5
C1A—C2A—H2B	109.5	C1B—C2B—H2B2	109.5
H2A—C2A—H2B	109.5	H2B1—C2B—H2B2	109.5
C1A—C2A—H2C	109.5	C1B—C2B—H2B3	109.5
H2A—C2A—H2C	109.5	H2B1—C2B—H2B3	109.5
H2B—C2A—H2C	109.5	H2B2—C2B—H2B3	109.5
N3A—C3A—C4A	121.63 (13)	N3B—C3B—C4B	131.33 (14)
N3A—C3A—C1A	132.39 (14)	N3B—C3B—C1B	122.16 (14)
C4A—C3A—C1A	105.89 (13)	C4B—C3B—C1B	106.50 (13)
N1A—C4A—C3A	105.30 (13)	N1B—C4B—C3B	104.92 (13)
N1A—C4A—C5A	123.80 (14)	N1B—C4B—C5B	122.65 (14)
C3A—C4A—C5A	130.89 (14)	C3B—C4B—C5B	132.42 (14)
C4A—C5A—H5A	109.5	C4B—C5B—H5B1	109.5
C4A—C5A—H5B	109.5	C4B—C5B—H5B2	109.5
H5A—C5A—H5B	109.5	H5B1—C5B—H5B2	109.5
C4A—C5A—H5C	109.5	C4B—C5B—H5B3	109.5
H5A—C5A—H5C	109.5	H5B1—C5B—H5B3	109.5
H5B—C5A—H5C	109.5	H5B2—C5B—H5B3	109.5
C4A—N1A—N2A—C1A	0.03 (17)	C4B—N1B—N2B—C1B	−0.10 (17)
N1A—N2A—C1A—C3A	−0.15 (16)	N1B—N2B—C1B—C3B	0.46 (17)
N1A—N2A—C1A—C2A	−179.56 (13)	N1B—N2B—C1B—C2B	−178.40 (13)
O1A—N3A—C3A—C4A	178.61 (13)	O1B—N3B—C3B—C4B	2.4 (2)
O1A—N3A—C3A—C1A	2.4 (2)	O1B—N3B—C3B—C1B	−179.01 (14)
N2A—C1A—C3A—N3A	176.84 (15)	N2B—C1B—C3B—N3B	−179.59 (13)
C2A—C1A—C3A—N3A	−3.8 (3)	C2B—C1B—C3B—N3B	−0.8 (2)
N2A—C1A—C3A—C4A	0.22 (16)	N2B—C1B—C3B—C4B	−0.65 (17)
C2A—C1A—C3A—C4A	179.57 (15)	C2B—C1B—C3B—C4B	178.11 (15)
N2A—N1A—C4A—C3A	0.11 (17)	N2B—N1B—C4B—C3B	−0.30 (16)
N2A—N1A—C4A—C5A	179.38 (14)	N2B—N1B—C4B—C5B	178.69 (13)
N3A—C3A—C4A—N1A	−177.26 (14)	N3B—C3B—C4B—N1B	179.36 (15)
C1A—C3A—C4A—N1A	−0.19 (16)	C1B—C3B—C4B—N1B	0.56 (16)
N3A—C3A—C4A—C5A	3.5 (3)	N3B—C3B—C4B—C5B	0.5 (3)
C1A—C3A—C4A—C5A	−179.39 (16)	C1B—C3B—C4B—C5B	−178.29 (15)

D—H···A	D—H	H···A	D···A	D—H···A
N1B—H1B···O1Ai	0.954 (18)	1.802 (18)	2.7526 (16)	174.0 (15)
N1A—H1A···N2Bii	0.915 (19)	1.95 (2)	2.8544 (18)	171.5 (16)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1B—H1B⋯O1Ai	0.954 (18)	1.802 (18)	2.7526 (16)	174.0 (15)
N1A—H1A⋯N2Bii	0.915 (19)	1.95 (2)	2.8544 (18)	171.5 (16)

Symmetry codes: (i) ; (ii) .