3,5-Di­fluoro-4-nitro­pyridine N-oxide and 3,5-di­amino-4-nitro­pyridine N-oxide monohydrate

The mol­ecule of 3,5-di­fluoro-4-nitro­pyridine N-oxide, C₅H₂F₂N₂O₃, is twisted around the C-NO₂ bond by 38.5 (1)°, while the 3,5-di­amino analogue, 3,5-di­amino-4-nitro­pyridine N-oxide monohydrate, C₅H₆N₄O₃·H₂O, adopts a planar conformation stabilized by intramolecular hydrogen bonds, with a significant redistribution of [pi] electrons.

Computing details

For both compounds, data collection: SMART (Siemens, 1995); cell refinement: SMART; data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXTL (Bruker, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

(I) 3,5-difluoro-4-nitropyridine N-oxide

Crystal data

C5H2F2N2O3	Dx = 1.820 Mg m^−3
Mr = 176.09	Melting point: 124° C K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 5.479 (2) Å	Cell parameters from 449 reflections
b = 10.840 (4) Å	θ = 10.0–23.0°
c = 11.159 (3) Å	µ = 0.19 mm^−1
β = 104.12 (1)°	T = 295 K
V = 642.7 (4) Å^3	Block, light yellow
Z = 4	0.35 × 0.25 × 0.20 mm
F(000) = 352

Data collection

SMART 1K CCD area-detector diffractometer	1086 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.032
Graphite monochromator	θmax = 27.5°, θmin = 2.7°
Detector resolution: 8 pixels mm^-1	h = −7→5
ω scans	k = −11→14
4314 measured reflections	l = −14→14
1469 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.040	All H-atom parameters refined
wR(F^2) = 0.104	w = 1/[σ^2(Fo^2) + (0.030P)^2 + 0.2547P] where P = (Fo^2 + 2Fc^2)/3
S = 1.14	(Δ/σ)max = 0.003
1469 reflections	Δρmax = 0.16 e Å^−3
118 parameters	Δρmin = −0.15 e Å^−3
0 restraints	Extinction correction: SHELXTL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.054 (5)

Special details

Experimental. The data collection nominally covered over a hemisphere of reciprocal space, by a combination of 4 sets of ω scans; each set at different φ and/or 2θ angles and each scan (10 sec exposure) covering 0.3° in ω. Crystal decay was monitored by repeating 50 initial frames at the end of data collection and comparing 41 duplicate reflections. Crystal to detector distance 4.54 cm.

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.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.6315 (3)	0.53826 (15)	0.35891 (14)	0.0434 (4)
C2	0.6757 (4)	0.61027 (19)	0.46240 (19)	0.0440 (5)
H2	0.817 (4)	0.594 (2)	0.524 (2)	0.061 (7)*
C3	0.5163 (4)	0.70703 (18)	0.46799 (17)	0.0420 (5)
C4	0.3073 (3)	0.73343 (17)	0.37154 (17)	0.0400 (4)
C5	0.2711 (3)	0.65693 (18)	0.26861 (17)	0.0418 (5)
C6	0.4314 (4)	0.56114 (19)	0.26238 (19)	0.0452 (5)
H6	0.411 (4)	0.511 (2)	0.195 (2)	0.056 (6)*
O1	0.7806 (3)	0.44597 (15)	0.35385 (14)	0.0640 (5)
F3	0.5653 (2)	0.77428 (13)	0.57141 (11)	0.0638 (4)
N4	0.1388 (3)	0.83620 (16)	0.37957 (16)	0.0493 (4)
O41	−0.0870 (3)	0.81918 (16)	0.33561 (18)	0.0714 (5)
O42	0.2333 (3)	0.93172 (14)	0.42902 (16)	0.0674 (5)
F5	0.0801 (2)	0.67666 (12)	0.17059 (11)	0.0640 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0450 (9)	0.0417 (9)	0.0425 (9)	0.0058 (7)	0.0086 (7)	0.0026 (7)
C2	0.0400 (10)	0.0500 (11)	0.0394 (10)	0.0006 (9)	0.0045 (8)	0.0022 (9)
C3	0.0418 (10)	0.0464 (11)	0.0373 (10)	−0.0039 (8)	0.0087 (8)	−0.0033 (8)
C4	0.0369 (10)	0.0377 (9)	0.0463 (11)	−0.0017 (8)	0.0116 (8)	0.0028 (8)
C5	0.0382 (10)	0.0417 (10)	0.0401 (10)	−0.0022 (8)	−0.0011 (8)	0.0042 (8)
C6	0.0504 (12)	0.0426 (11)	0.0395 (10)	0.0003 (9)	0.0047 (9)	−0.0021 (9)
O1	0.0658 (10)	0.0593 (10)	0.0620 (10)	0.0265 (8)	0.0062 (8)	−0.0039 (8)
F3	0.0642 (8)	0.0720 (9)	0.0491 (7)	0.0071 (6)	0.0017 (6)	−0.0199 (6)
N4	0.0483 (10)	0.0462 (10)	0.0556 (11)	0.0058 (8)	0.0169 (8)	0.0066 (8)
O41	0.0436 (9)	0.0709 (11)	0.1007 (14)	0.0100 (8)	0.0194 (9)	0.0095 (10)
O42	0.0835 (12)	0.0447 (9)	0.0731 (11)	0.0051 (8)	0.0175 (9)	−0.0089 (8)
F5	0.0578 (8)	0.0642 (8)	0.0554 (8)	0.0093 (6)	−0.0144 (6)	−0.0037 (6)

Geometric parameters (Å, º)

N1—O1	1.301 (2)	C4—C5	1.391 (3)
N1—C6	1.359 (3)	C4—N4	1.464 (2)
N1—C2	1.366 (3)	C5—F5	1.334 (2)
C2—C3	1.376 (3)	C5—C6	1.372 (3)
C2—H2	0.92 (2)	C6—H6	0.91 (2)
C3—F3	1.336 (2)	N4—O42	1.227 (2)
C3—C4	1.396 (3)	N4—O41	1.228 (2)
O1—N1—C6	119.96 (17)	C3—C4—N4	121.31 (17)
O1—N1—C2	119.51 (17)	F5—C5—C6	117.61 (18)
C6—N1—C2	120.52 (17)	F5—C5—C4	120.45 (17)
N1—C2—C3	119.39 (19)	C6—C5—C4	121.92 (18)
N1—C2—H2	117.4 (15)	N1—C6—C5	120.02 (19)
C3—C2—H2	123.1 (15)	N1—C6—H6	117.5 (14)
F3—C3—C2	117.34 (18)	C5—C6—H6	122.5 (14)
F3—C3—C4	120.55 (17)	O42—N4—O41	125.44 (18)
C2—C3—C4	122.09 (18)	O42—N4—C4	117.81 (18)
C5—C4—C3	116.05 (17)	O41—N4—C4	116.76 (18)
C5—C4—N4	122.63 (18)

(II) 3,5-diamino-4-nitropyridine N-oxide monohydrate

Crystal data

C5H6N4O3·H2O	Dx = 1.646 Mg m^−3
Mr = 188.15	Melting point: >300° C (decomp.) K
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 391 reflections
a = 7.000 (1) Å	θ = 10.4–25.5°
b = 13.123 (1) Å	µ = 0.14 mm^−1
c = 8.263 (1) Å	T = 150 K
V = 759.05 (15) Å^3	Prism, red
Z = 4	0.40 × 0.15 × 0.08 mm
F(000) = 392

Data collection

SMART 1K CCD area-detector diffractometer	837 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.051
Graphite monochromator	θmax = 27.5°, θmin = 2.9°
Detector resolution: 8 pixels mm^-1	h = −9→9
ω scans	k = −16→17
5153 measured reflections	l = −10→10
925 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.035	All H-atom parameters refined
wR(F^2) = 0.093	w = 1/[σ^2(Fo^2) + (0.0515P)^2 + 0.3363P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max = 0.003
925 reflections	Δρmax = 0.21 e Å^−3
149 parameters	Δρmin = −0.22 e Å^−3
1 restraint	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0 (10)

Special details

Experimental. The data collection nominally covered over a hemisphere of reciprocal space, by a combination of 4 sets of ω scans; each set at different φ and/or 2θ angles and each scan (20 sec exposure) covering 0.3° in ω. Crystal decay was monitored by repeating 50 initial frames at the end of data collection and comparing 102 duplicate reflections. Crystal to detector distance 4.54 cm.

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. The absolute structure (polarity) could not be determined reliably for the lack of anomalously scattering atoms. Of 1682 unique reflections measured, 757 Friedel pairs were merged.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.3290 (3)	0.47510 (15)	0.2312 (3)	0.0147 (4)
C2	0.4014 (4)	0.4299 (2)	0.0987 (4)	0.0156 (6)
H2	0.444 (5)	0.473 (3)	0.011 (5)	0.025 (9)*
C3	0.4200 (4)	0.32302 (18)	0.0905 (3)	0.0136 (5)
C4	0.3529 (4)	0.26489 (17)	0.2262 (4)	0.0129 (5)
C5	0.2817 (4)	0.3158 (2)	0.3684 (3)	0.0140 (5)
C6	0.2721 (4)	0.4232 (2)	0.3626 (4)	0.0154 (6)
H6	0.225 (5)	0.461 (2)	0.446 (5)	0.014 (8)*
O1	0.3120 (3)	0.57640 (13)	0.2305 (3)	0.0197 (5)
O41	0.4256 (3)	0.11343 (14)	0.0994 (3)	0.0205 (5)
O42	0.2907 (3)	0.10538 (15)	0.3355 (3)	0.0226 (5)
N3	0.4969 (4)	0.28535 (18)	−0.0446 (3)	0.0177 (5)
H31	0.532 (5)	0.326 (3)	−0.127 (5)	0.016 (6)*
H32	0.506 (5)	0.225 (3)	−0.060 (5)	0.016 (6)*
N4	0.3572 (3)	0.15663 (14)	0.2199 (3)	0.0138 (4)
N5	0.2229 (4)	0.2695 (2)	0.5040 (3)	0.0182 (5)
H51	0.231 (5)	0.199 (2)	0.507 (4)	0.007 (7)*
H52	0.190 (5)	0.306 (3)	0.584 (5)	0.021 (9)*
O1W	−0.0783 (3)	0.60634 (15)	0.2584 (3)	0.0209 (5)
H1W	−0.118 (7)	0.551 (4)	0.274 (6)	0.054 (15)*
H2W	0.047 (7)	0.593 (3)	0.242 (7)	0.057 (14)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0157 (9)	0.0110 (9)	0.0173 (11)	−0.0006 (8)	−0.0015 (10)	−0.0039 (11)
C2	0.0167 (13)	0.0139 (12)	0.0163 (13)	−0.0017 (10)	0.0027 (11)	0.0017 (12)
C3	0.0110 (13)	0.0133 (11)	0.0166 (13)	0.0022 (9)	−0.0014 (11)	−0.0017 (12)
C4	0.0142 (10)	0.0118 (11)	0.0128 (12)	0.0001 (9)	−0.0018 (10)	0.0015 (13)
C5	0.0122 (12)	0.0151 (12)	0.0149 (13)	−0.0012 (10)	−0.0013 (10)	−0.0015 (12)
C6	0.0166 (13)	0.0158 (12)	0.0139 (13)	0.0015 (10)	0.0028 (11)	−0.0039 (11)
O1	0.0273 (10)	0.0083 (8)	0.0234 (11)	0.0003 (7)	−0.0033 (10)	−0.0012 (9)
O41	0.0311 (12)	0.0136 (9)	0.0167 (10)	0.0015 (8)	0.0041 (10)	−0.0027 (9)
O42	0.0310 (12)	0.0132 (9)	0.0236 (12)	−0.0007 (8)	0.0100 (10)	0.0038 (9)
N3	0.0251 (13)	0.0116 (11)	0.0163 (13)	0.0020 (10)	0.0057 (10)	0.0003 (11)
N4	0.0126 (9)	0.0120 (9)	0.0168 (11)	−0.0002 (8)	0.0007 (9)	0.0002 (12)
N5	0.0239 (13)	0.0146 (12)	0.0162 (13)	0.0021 (10)	0.0067 (11)	0.0002 (10)
O1W	0.0283 (11)	0.0133 (9)	0.0212 (11)	0.0003 (8)	−0.0038 (9)	−0.0010 (9)

Geometric parameters (Å, º)

N1—O1	1.335 (3)	C5—C6	1.411 (4)
N1—C6	1.342 (4)	C6—H6	0.91 (4)
N1—C2	1.344 (4)	O41—N4	1.242 (3)
C2—C3	1.410 (3)	O42—N4	1.258 (3)
C2—H2	0.96 (4)	N3—H31	0.90 (4)
C3—N3	1.334 (4)	N3—H32	0.80 (3)
C3—C4	1.435 (4)	N5—H51	0.92 (3)
C4—N4	1.422 (3)	N5—H52	0.85 (4)
C4—C5	1.441 (4)	O1W—H1W	0.79 (5)
C5—N5	1.339 (4)	O1W—H2W	0.90 (5)
O1—N1—C6	118.9 (2)	C6—C5—C4	116.9 (2)
O1—N1—C2	118.0 (2)	N1—C6—C5	121.3 (3)
C6—N1—C2	123.1 (2)	N1—C6—H6	116 (2)
N1—C2—C3	120.9 (3)	C5—C6—H6	122 (2)
N1—C2—H2	118 (2)	C3—N3—H31	121 (2)
C3—C2—H2	121 (2)	C3—N3—H32	122 (3)
N3—C3—C2	116.5 (3)	H31—N3—H32	116 (4)
N3—C3—C4	126.1 (2)	O41—N4—O42	120.52 (19)
C2—C3—C4	117.4 (2)	O41—N4—C4	119.6 (2)
N4—C4—C3	119.7 (2)	O42—N4—C4	119.9 (2)
N4—C4—C5	120.0 (2)	C5—N5—H51	117 (2)
C3—C4—C5	120.2 (2)	C5—N5—H52	119 (2)
N5—C5—C6	117.8 (2)	H51—N5—H52	124 (3)
N5—C5—C4	125.3 (2)	H1W—O1W—H2W	101 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H31···O1^i	0.90 (4)	2.05 (4)	2.922 (3)	162 (3)
N3—H32···O41	0.80 (3)	2.05 (4)	2.599 (3)	125 (4)
N3—H32···O1W^ii	0.80 (3)	2.22 (4)	2.915 (3)	145 (4)
N5—H51···O42	0.92 (3)	1.92 (3)	2.609 (3)	130 (3)
N5—H52···O1W^iii	0.85 (4)	2.00 (4)	2.845 (3)	172 (4)
O1W—H1W···O42^iv	0.79 (5)	2.21 (5)	2.994 (3)	175 (5)
O1W—H2W···O1	0.90 (5)	1.87 (5)	2.770 (3)	173 (5)

Symmetry codes: (i) −x+1, −y+1, z−1/2; (ii) −x+1/2, y−1/2, z−1/2; (iii) −x, −y+1, z+1/2; (iv) x−1/2, −y+1/2, z.