5,5-Dihydroxy-barbituric acid 1,4-dioxane hemisolvate.

The asymmetric unit of the title compound,, C(4)H(4)N(2)O(5)·0.5C(4)H(8)O(2), contains one molecule of 5,5-dihydroxybarbituric acid with a nearly planar barbiturate ring and half a molecule of 1,4-dioxane. The geometry of the centrosymmetric dioxane molecule is close to an ideal chair conformation. The crystal structure exhibits a complex three-dimensional hydrogen-bonded network. Barbiturate mol-ecules are connected to one another via N-H⋯O=C, O-H⋯O=C and N-H⋯O(hydr-oxy) inter-actions, while the barbituric acid mol-ecule is linked to dioxane by an O-H⋯O contact.

Related literature

For the crystal structure of unsolvated 5,5-dihydroxy­barbituric acid, see: Singh (1965 ▶); Harrowfield et al. (1989 ▶). For the related monohydrate, see Lewis & Tocher (2004a ▶). For the related trihydrate, see Mootz & Jeffrey (1965 ▶); Lewis & Tocher (2004b ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C4H4N2O5·0.5C4H8O2

M = 204.14

Triclinic,

a = 6.0232 (3) Å

b = 8.3954 (4) Å

c = 8.6858 (5) Å

α = 106.007 (4)°

β = 94.459 (3)°

γ = 110.126 (3)°

V = 389.09 (3) Å3

Z = 2

Mo Kα radiation

μ = 0.16 mm−1

T = 120 K

0.10 × 0.10 × 0.10 mm

Data collection

Bruker-Nonius Roper CCD camera on κ-goniostat diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2007 ▶) T min = 0.984, T max = 0.984

5726 measured reflections

1529 independent reflections

1198 reflections with I > 2σ(I)

R int = 0.049

Refinement

R[F 2 > 2σ(F 2)] = 0.045

wR(F 2) = 0.131

S = 1.01

1529 reflections

148 parameters

4 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.25 e Å−3

Δρmin = −0.29 e Å−3

Data collection: COLLECT (Hooft, 1998 ▶); cell refinement: DENZO (Otwinowski & Minor, 1997 ▶) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL (Sheldrick, 2008 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810015321/jh2150sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810015321/jh2150Isup2.hkl

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

C4H4N2O5·0.5C4H8O2	Z = 2
Mr = 204.14	F(000) = 212
Triclinic, P1	Dx = 1.742 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.0232 (3) Å	Cell parameters from 3190 reflections
b = 8.3954 (4) Å	θ = 2.9–26.0°
c = 8.6858 (5) Å	µ = 0.16 mm−1
α = 106.007 (4)°	T = 120 K
β = 94.459 (3)°	Block, colourless
γ = 110.126 (3)°	0.10 × 0.10 × 0.10 mm
V = 389.09 (3) Å3

Bruker-Nonius Roper CCD camera on κ-goniostat diffractometer	1529 independent reflections
Radiation source: Bruker–Nonius FR591 rotating anode	1198 reflections with I > 2σ(I)
graphite	Rint = 0.049
Detector resolution: 9.091 pixels mm-1	θmax = 26.0°, θmin = 3.6°
φ & ω scans	h = −7→7
Absorption correction: multi-scan (SADABS; Sheldrick, 2007)	k = −10→10
Tmin = 0.984, Tmax = 0.984	l = −10→10
5726 measured reflections

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.045	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.131	w = 1/[σ2(Fo2) + (0.0787P)2 + 0.0767P] where P = (Fo2 + 2Fc2)/3
S = 1.01	(Δ/σ)max < 0.001
1529 reflections	Δρmax = 0.25 e Å−3
148 parameters	Δρmin = −0.29 e Å−3
4 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.062 (16)

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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
N1	0.7757 (3)	0.7817 (2)	0.3822 (2)	0.0204 (4)
H1N	0.934 (3)	0.835 (4)	0.398 (4)	0.061 (10)*
N3	0.4114 (3)	0.5803 (2)	0.2073 (2)	0.0175 (4)
H3N	0.342 (4)	0.506 (3)	0.107 (2)	0.029 (6)*
O2	0.7627 (3)	0.65461 (19)	0.11484 (17)	0.0242 (4)
O4	0.0683 (3)	0.4836 (2)	0.29980 (18)	0.0264 (4)
O6	0.8029 (3)	0.90452 (19)	0.65175 (17)	0.0265 (4)
O7	0.3029 (2)	0.83394 (18)	0.53542 (18)	0.0212 (4)
H7O	0.360 (6)	0.895 (4)	0.638 (2)	0.064 (10)*
O8	0.3738 (3)	0.60819 (19)	0.60882 (17)	0.0221 (4)
H8O	0.228 (3)	0.574 (4)	0.615 (4)	0.060 (10)*
C2	0.6555 (4)	0.6706 (3)	0.2277 (2)	0.0189 (5)
C4	0.2802 (4)	0.5806 (3)	0.3280 (2)	0.0185 (5)
C6	0.6801 (3)	0.8039 (3)	0.5200 (2)	0.0186 (5)
C5	0.4070 (3)	0.7064 (3)	0.5010 (2)	0.0178 (5)
O1S	0.4460 (2)	1.04067 (18)	0.85656 (16)	0.0201 (4)
C1S	0.6766 (4)	1.1366 (3)	0.9647 (3)	0.0218 (5)
H1S1	0.6742	1.2450	1.0457	0.030 (6)*
H1S2	0.8027	1.1755	0.9014	0.013 (5)*
C2S	0.2647 (3)	0.9800 (3)	0.9481 (2)	0.0213 (5)
H2S1	0.1066	0.9113	0.8733	0.031 (6)*
H2S2	0.2530	1.0848	1.0287	0.036 (7)*

	U11	U22	U33	U12	U13	U23
N1	0.0145 (9)	0.0210 (9)	0.0182 (10)	0.0021 (8)	0.0036 (7)	0.0005 (7)
N3	0.0161 (9)	0.0192 (9)	0.0127 (9)	0.0042 (7)	0.0020 (7)	0.0019 (7)
O2	0.0192 (8)	0.0258 (8)	0.0188 (8)	0.0030 (6)	0.0070 (6)	−0.0003 (6)
O4	0.0159 (8)	0.0307 (8)	0.0211 (8)	0.0004 (7)	0.0042 (6)	0.0016 (6)
O6	0.0191 (8)	0.0319 (9)	0.0186 (8)	0.0056 (7)	0.0014 (6)	−0.0007 (6)
O7	0.0190 (8)	0.0229 (8)	0.0200 (8)	0.0092 (6)	0.0031 (6)	0.0031 (6)
O8	0.0214 (8)	0.0279 (8)	0.0202 (8)	0.0096 (7)	0.0070 (6)	0.0116 (6)
C2	0.0179 (10)	0.0165 (10)	0.0187 (11)	0.0036 (8)	0.0040 (9)	0.0039 (8)
C4	0.0170 (10)	0.0187 (10)	0.0189 (11)	0.0056 (8)	0.0042 (8)	0.0061 (8)
C6	0.0166 (10)	0.0198 (10)	0.0180 (11)	0.0060 (8)	0.0036 (8)	0.0053 (8)
C5	0.0162 (10)	0.0199 (10)	0.0182 (11)	0.0069 (8)	0.0054 (8)	0.0068 (8)
O1S	0.0158 (7)	0.0249 (8)	0.0162 (8)	0.0054 (6)	0.0027 (6)	0.0044 (6)
C1S	0.0152 (10)	0.0225 (10)	0.0205 (11)	0.0019 (8)	−0.0004 (8)	0.0039 (8)
C2S	0.0138 (10)	0.0290 (11)	0.0182 (11)	0.0059 (9)	0.0040 (8)	0.0060 (9)

N1—C6	1.362 (3)	O8—H8O	0.834 (18)
N1—C2	1.374 (3)	C4—C5	1.532 (3)
N1—H1N	0.886 (18)	C6—C5	1.536 (3)
N3—C4	1.361 (3)	O1S—C2S	1.435 (2)
N3—C2	1.373 (3)	O1S—C1S	1.439 (2)
N3—H3N	0.883 (17)	C1S—C2Si	1.504 (3)
O2—C2	1.217 (2)	C1S—H1S1	0.9900
O4—C4	1.216 (2)	C1S—H1S2	0.9900
O6—C6	1.214 (2)	C2S—C1Si	1.504 (3)
O7—C5	1.394 (2)	C2S—H2S1	0.9900
O7—H7O	0.867 (18)	C2S—H2S2	0.9900
O8—C5	1.392 (2)
C6—N1—C2	126.66 (17)	O8—C5—C4	109.42 (16)
C6—N1—H1N	115 (2)	O7—C5—C4	105.53 (15)
C2—N1—H1N	118 (2)	O8—C5—C6	106.79 (16)
C4—N3—C2	125.94 (17)	O7—C5—C6	108.58 (15)
C4—N3—H3N	119.4 (16)	C4—C5—C6	114.24 (16)
C2—N3—H3N	114.2 (16)	C2S—O1S—C1S	109.37 (15)
C5—O7—H7O	105 (2)	O1S—C1S—C2Si	110.63 (16)
C5—O8—H8O	107 (2)	O1S—C1S—H1S1	109.5
O2—C2—N3	122.08 (19)	C2Si—C1S—H1S1	109.5
O2—C2—N1	120.85 (18)	O1S—C1S—H1S2	109.5
N3—C2—N1	117.07 (17)	C2Si—C1S—H1S2	109.5
O4—C4—N3	121.06 (19)	H1S1—C1S—H1S2	108.1
O4—C4—C5	120.76 (18)	O1S—C2S—C1Si	110.95 (16)
N3—C4—C5	118.18 (17)	O1S—C2S—H2S1	109.4
O6—C6—N1	121.57 (18)	C1Si—C2S—H2S1	109.4
O6—C6—C5	120.87 (17)	O1S—C2S—H2S2	109.4
N1—C6—C5	117.43 (17)	C1Si—C2S—H2S2	109.4
O8—C5—O7	112.40 (16)	H2S1—C2S—H2S2	108.0
C4—N3—C2—O2	175.20 (18)	N3—C4—C5—O7	112.76 (19)
C4—N3—C2—N1	−5.1 (3)	O4—C4—C5—C6	173.36 (17)
C6—N1—C2—O2	−176.10 (18)	N3—C4—C5—C6	−6.4 (2)
C6—N1—C2—N3	4.2 (3)	O6—C6—C5—O8	−57.3 (2)
C2—N3—C4—O4	−173.22 (18)	N1—C6—C5—O8	126.73 (18)
C2—N3—C4—C5	6.6 (3)	O6—C6—C5—O7	64.2 (2)
C2—N1—C6—O6	179.18 (18)	N1—C6—C5—O7	−111.85 (19)
C2—N1—C6—C5	−4.8 (3)	O6—C6—C5—C4	−178.39 (17)
O4—C4—C5—O8	53.7 (2)	N1—C6—C5—C4	5.6 (2)
N3—C4—C5—O8	−126.09 (18)	C2S—O1S—C1S—C2Si	57.5 (2)
O4—C4—C5—O7	−67.4 (2)	C1S—O1S—C2S—C1Si	−57.7 (2)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O6ii	0.89 (2)	2.39 (3)	3.068 (2)	134 (3)
N1—H1N···O7iii	0.89 (2)	2.44 (2)	3.180 (2)	141 (3)
N3—H3N···O2iv	0.88 (2)	1.93 (2)	2.810 (2)	172 (2)
O7—H7O···O1S	0.87 (2)	1.87 (2)	2.732 (2)	171 (3)
O8—H8O···O4v	0.83 (2)	1.95 (2)	2.751 (2)	162 (3)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯O6i	0.89 (2)	2.39 (3)	3.068 (2)	134 (3)
N1—H1N⋯O7ii	0.89 (2)	2.44 (2)	3.180 (2)	141 (3)
N3—H3N⋯O2iii	0.88 (2)	1.93 (2)	2.810 (2)	172 (2)
O7—H7O⋯O1S	0.87 (2)	1.87 (2)	2.732 (2)	171 (3)
O8—H8O⋯O4iv	0.83 (2)	1.95 (2)	2.751 (2)	162 (3)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) .