2-Ureidopyridine N-oxide monohydrate

In the title compound, C₆H₇N₃O₂·H₂O, all atoms of 2-ureidopyridine N-oxide mol­ecule are approximately coplanar and adjacent mol­ecules are connected by strong hydrogen bonds, resulting in a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.034
• wR factor = 0.092
• Data-to-parameter ratio = 11.1

checkCIF/PLATON results

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Alert level C
PLAT063_ALERT_3_C Crystal Probably too Large for Beam Size .......       0.64 mm

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          3

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The asymmetric unit of the title compound, (I), there are one 1-(pyridin-2-yl-N-oxide)urea molecule and one discrete water molecule (Fig. 1). All atoms of 1-(pyridin-2-yl-N-oxide)urea molecule are approximately coplanar, the maximum deviation from the least-squares plane through the whole molecule being 0.096 Å for O3. In the crystal of (I) adjacent molecules are connected by strong hydrogen bonds, which resulting in a 3-D network (Fig. 2).

Related literature

Please supply related literature

S2. Experimental

1-(pyridin-2-yl-N-oxide)urea was obtained commercially. Crystals of the title compound were acquired after 0.153 g (0.001 mol) 1-(pyridin-2-yl-N-oxide)urea were recrystallized in 30 ml e thanol by means of solvent evaporation.

S3. Refinement

The H atoms bonding to C atoms were located at calculated positions and refined as riding on their parent atoms with the bond length fixed to 0.93Å, with U_iso(H) being 1.2 times U_eq(C). The H atoms of water molecules were found in electron density maps and refined with bond length fixed to 0.82Å and with i>U_iso(H) = 1.2 times U_eq(O). The H atoms bonding to N1 were located at calculated positions while the H atoms connect with N2 were found in electron density maps and were refined with the bond lengths fixed to 0.86Å and with i>U_iso(H) = 1.5 times U_eq(N).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1996); software used to prepare material for publication: SHELXTL (Siemens, 1996).

Figures

	Fig. 1. The asymmetric unit of (I), showing 50% probability displacement ellipsoids.
	Fig. 2. The packing diagram of (I), viewed along a axis. Hydrogen bonds are shown as dash lines.

2-Ureidopyridine N-oxide monohydrate

Crystal data

C6H7N3O2·H2O	F(000) = 360.0
Mr = 171.16	Dx = 1.504 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2597 reflections
a = 13.1277 (17) Å	θ = 1.0–28.3°
b = 4.1085 (5) Å	µ = 0.12 mm^−1
c = 15.419 (2) Å	T = 293 K
β = 114.618 (2)°	Block, yellow
V = 756.03 (17) Å^3	0.64 × 0.13 × 0.09 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	862 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.055
Graphite monochromator	θmax = 25.0°, θmin = 2.7°
phi and ω scans	h = −15→15
4130 measured reflections	k = −4→4
1316 independent reflections	l = −18→18

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.034	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.092	w = 1/[σ^2(Fo^2) + (0.0526P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.90	(Δ/σ)max < 0.001
1316 reflections	Δρmax = 0.13 e Å^−3
119 parameters	Δρmin = −0.13 e Å^−3
3 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.026 (5)

Special details

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.

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

	x	y	z	Uiso*/Ueq
C1	0.73625 (15)	1.2059 (4)	−0.12921 (12)	0.0502 (5)
C2	0.77990 (14)	0.9178 (4)	0.02165 (11)	0.0455 (4)
C3	0.88443 (14)	0.7903 (4)	0.04058 (12)	0.0544 (5)
H3	0.9173	0.8308	−0.0014	0.065*
C4	0.94047 (15)	0.6049 (5)	0.12032 (13)	0.0607 (5)
H4	1.0110	0.5217	0.1326	0.073*
C5	0.89145 (16)	0.5428 (5)	0.18212 (13)	0.0629 (5)
H5	0.9285	0.4181	0.2366	0.076*
C6	0.78795 (16)	0.6670 (5)	0.16209 (13)	0.0642 (5)
H6	0.7544	0.6248	0.2035	0.077*
H2	0.6539 (8)	1.185 (4)	−0.0503 (12)	0.077*
H1A	0.5125 (18)	0.351 (2)	0.0890 (14)	0.096*
H1B	0.5431 (15)	0.662 (4)	0.0966 (14)	0.096*
N1	0.65659 (13)	1.3944 (4)	−0.19130 (10)	0.0615 (5)
H1C	0.6626	1.4634	−0.2416	0.074*
H1D	0.5991	1.4470	−0.1811	0.074*
N2	0.71368 (11)	1.1122 (4)	−0.05211 (10)	0.0488 (4)
N3	0.73273 (11)	0.8497 (4)	0.08372 (9)	0.0523 (4)
O1	0.50430 (13)	0.5297 (3)	0.10892 (10)	0.0701 (4)
O2	0.63227 (11)	0.9703 (3)	0.06613 (9)	0.0738 (5)
O3	0.82049 (10)	1.1191 (3)	−0.13782 (8)	0.0650 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0547 (11)	0.0590 (12)	0.0452 (9)	−0.0185 (9)	0.0290 (9)	−0.0115 (9)
C2	0.0493 (10)	0.0481 (11)	0.0459 (9)	−0.0121 (8)	0.0267 (8)	−0.0096 (8)
C3	0.0500 (10)	0.0631 (13)	0.0593 (11)	−0.0106 (9)	0.0317 (9)	−0.0091 (9)
C4	0.0488 (10)	0.0634 (13)	0.0691 (13)	−0.0034 (9)	0.0238 (10)	−0.0061 (10)
C5	0.0668 (13)	0.0643 (13)	0.0560 (11)	0.0040 (10)	0.0238 (10)	0.0039 (9)
C6	0.0809 (14)	0.0660 (13)	0.0600 (12)	0.0081 (11)	0.0435 (11)	0.0097 (11)
N1	0.0623 (10)	0.0807 (12)	0.0503 (9)	−0.0052 (9)	0.0323 (8)	0.0089 (8)
N2	0.0503 (8)	0.0583 (10)	0.0474 (8)	−0.0046 (7)	0.0298 (7)	0.0009 (7)
N3	0.0578 (9)	0.0558 (9)	0.0565 (9)	0.0046 (7)	0.0369 (8)	0.0056 (8)
O1	0.0862 (10)	0.0710 (11)	0.0706 (9)	0.0079 (8)	0.0501 (8)	0.0049 (8)
O2	0.0744 (9)	0.0859 (10)	0.0886 (10)	0.0275 (7)	0.0611 (8)	0.0305 (7)
O3	0.0600 (8)	0.0930 (11)	0.0574 (8)	−0.0076 (7)	0.0396 (7)	−0.0073 (7)

Geometric parameters (Å, º)

C1—O3	1.2208 (19)	C5—C6	1.361 (2)
C1—N1	1.332 (2)	C5—H5	0.9300
C1—N2	1.394 (2)	C6—N3	1.349 (2)
C2—N2	1.365 (2)	C6—H6	0.9300
C2—N3	1.3681 (19)	N1—H1C	0.8600
C2—C3	1.382 (2)	N1—H1D	0.8600
C3—C4	1.371 (2)	N2—H2	0.851 (14)
C3—H3	0.9300	N3—O2	1.3268 (16)
C4—C5	1.378 (3)	O1—H1A	0.820 (12)
C4—H4	0.9300	O1—H1B	0.82 (2)
O3—C1—N1	124.55 (16)	C4—C5—H5	120.5
O3—C1—N2	122.41 (17)	N3—C6—C5	121.68 (16)
N1—C1—N2	113.04 (15)	N3—C6—H6	119.2
N2—C2—N3	112.69 (14)	C5—C6—H6	119.2
N2—C2—C3	129.02 (15)	C1—N1—H1C	120.0
N3—C2—C3	118.28 (16)	C1—N1—H1D	120.0
C4—C3—C2	120.98 (16)	H1C—N1—H1D	120.0
C4—C3—H3	119.5	C2—N2—C1	125.76 (15)
C2—C3—H3	119.5	C2—N2—H2	117.0 (13)
C3—C4—C5	119.50 (18)	C1—N2—H2	117.2 (13)
C3—C4—H4	120.2	O2—N3—C6	120.56 (13)
C5—C4—H4	120.2	O2—N3—C2	118.79 (14)
C6—C5—C4	118.91 (18)	C6—N3—C2	120.64 (15)
C6—C5—H5	120.5	H1A—O1—H1B	108 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O2^i	0.82 (1)	2.35 (1)	3.0763 (18)	149 (2)
N2—H2···O1^ii	0.85 (1)	2.22 (1)	3.005 (2)	153 (2)
O1—H1B···O2	0.82 (2)	1.91 (2)	2.7310 (19)	179 (2)
N1—H1C···O3^iii	0.86	2.06	2.9232 (18)	179
N1—H1D···O1^ii	0.86	2.09	2.899 (2)	158

Symmetry codes: (i) x, y−1, z; (ii) −x+1, −y+2, −z; (iii) −x+3/2, y+1/2, −z−1/2.