8-(2-Hy­droxy­phen­yl)-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione

Booysen, I.; Hlela, T.; Ismail, M.; Gerber, T.; Hosten, E.; Betz, R.

doi:10.1107/S1600536811032417

organic compounds

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ISSN: 2056-9890

Volume 67| Part 9| September 2011| Page o2347

doi:10.1107/S1600536811032417

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8-(2-Hydroxyphenyl)-1,3-dimethyl-1H-purine-2,6(3H,7H)-dione

Irvin Booysen,^a Thulani Hlela,^a Muhammed Ismail,^a Thomas Gerber,^b Eric Hosten ^b and Richard Betz ^b ^*

^aUniversity of Kwazulu-Natal, School of Chemistry, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa, and ^bNelson Mandela Metropolitan University, Summerstrand Campus, Department of Chemistry, University Way, Summerstrand, PO Box 77000, Port Elizabeth 6031, South Africa
^*Correspondence e-mail: richard.betz@webmail.co.za

(Received 3 August 2011; accepted 10 August 2011; online 17 August 2011)

The title compound, C₁₃H₁₂N₄O₃, is an imidazole derivative featuring an annealed purine ring system. The benzimidazole-inspired moiety is essentially planar (r.m.s. of all fitted non-H atoms = 0.0205 Å). An intramolecular O—H⋯N hydrogen bond occurs. In the crystal, intermolecular N—H⋯O and C—H⋯O hydrogen bonds are observed, which connect the molecules into chains along [110]. The shortest centroid–centroid distance between two aromatic systems is 3.7771 (11) Å.

Related literature

For the crystal structure of benzimidazole, see: Krawczyk & Gdaniec (2005 ). For the crystal structure of hypoxanthinium nitrate monohydrate as an example of an oxopurine compound, see: Schmalle et al. (1990 ). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990 ); Bernstein et al. (1995 ). For puckering analysis, see: Cremer & Pople (1975 ). For general information about the chelate effect in coordination chemistry, see: Gade (1998 ).

Experimental

Crystal data

C₁₃H₁₂N₄O₃
M_r = 272.27
Monoclinic, P 2₁ /c
a = 8.6418 (5) Å
b = 5.9415 (3) Å
c = 23.4475 (10) Å
β = 91.275 (2)°
V = 1203.62 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 200 K
0.41 × 0.10 × 0.05 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ) T_min = 0.860, T_max = 1.000
10068 measured reflections
2975 independent reflections
1752 reflections with I > 2σ(I)
R_int = 0.043

Refinement

R[F² > 2σ(F²)] = 0.049
wR(F²) = 0.124
S = 1.01
2975 reflections
188 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯N2	0.84	1.86	2.611 (2)	148
N1—H71⋯O1ⁱ	0.97 (2)	1.78 (2)	2.746 (2)	175.4 (19)
C9—H9⋯O1ⁱ	0.95	2.37	3.294 (2)	164
C5—H5A⋯O3ⁱⁱ	0.98	2.58	3.234 (2)	124
Symmetry codes: (i) -x+1, -y+1, -z; (ii) -x+2, -y-1, -z.

Data collection: APEX2 (Bruker, 2010 ); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997 ) and Mercury (Macrae et al., 2008 ); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811032417/si2369sup1.cif

Supporting information file. DOI: 10.1107/S1600536811032417/si2369Isup2.cdx

Structure factors: contains datablock I. DOI: 10.1107/S1600536811032417/si2369Isup3.hkl

Supporting information file. DOI: 10.1107/S1600536811032417/si2369Isup4.cml

checkCIF report

Comment top

Chelate ligands have found widespread use in coordination chemistry due to the enhanced thermodynamic stability of resultant coordination compounds in relation to metal complexes exclusively applying comparable monodentate ligands (Gade 1998). Combining different sets of donor atoms in one chelate ligand molecule, a probe for testing and accomodating metal centers of different Lewis acidities is at hand. To enable comparative studies with envisioned coordination compounds, we determined the crystal structure of the title compound. The crystal structure of benzimidazole has been reported various times in the literature (e.g. Krawczyk & Gdaniec, 2005). In addition, several oxopurine derivatives have been the topic of crystal structure determinations (e.g. Schmalle et al., 1990).

The molecule features a benzimidazole-inspired backbone comprised of a 6-amino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione moiety which is annealed to a five-membered aromatic ring. This part of the molecule is essentially planar (r.m.s. of its fitted non-hydrogen atoms = 0.0205 Å). The small puckering amplitude (τ = 1.6 °) of the six-membered heterocycle precludes a conformation analysis (Cremer & Pople, 1975). The least-squares planes defined by the atoms of the phenyl ring on the one hand and the benzimidazole-type ring system on the other hand enclose an angle of 0.45 (10) ° (Fig. 1). Both C–N–C angles in the five-membered heterocycle are similar in value with 106.25 (15)° and 104.41 (15)°, with the smaller value found on the non-protonated nitrogen atom. However, these angles are smaller in value than the corresponding ones in hypoxanthinium nitrate monohydrate – invariably above 108 ° – where both nitrogen atoms bear a hydrogen atom (Schmalle et al., 1990).

In the crystal structure, intra- as well as intermolecular hydrogen bonds and C–H···O contacts whose range falls by more than 0.1 Å below the sum of van-der-Waals radii of atoms participating are observed. While the intramolecular hydrogen bonds are exclusively made up by the proton of the hydroxyl group as donor and the non-protonated nitrogen atom of the five-membered heterocycle, intermolecular hydrogen bonds are solely apparent between the amino group and one of the double-bonded oxygen atoms (Table 1). The C–H···O contacts can be separated in two groups: while one of the nitrogen-bound methyl groups forms a C–H···O contact involving the oxygen atom of the hydroxyl group, one of the aromatic C–H groups acts as donor for the double-bonded oxygen atom that is already part of the N–H···O type hydrogen bonds. In terms of graph-set analysis (Etter et al., 1990; Bernstein et al., 1995), the descriptor for the classical hydrogen bonds is S(6)R²₂(10) on the unitary level. For the C–H···O contacts, a R²₂(16)R²₂(18) descriptor on the same level is needed for description. In total, the molecules are connected to chains along [1 1 0]. The shortest intercentroid distance between two aromatic systems was measured at 3.7771 (11) Å (Fig. 2).

The packing of the title compound in the crystal is shown in Figure 3.

Related literature top

For the crystal structure of benzimidazole, see: Krawczyk & Gdaniec (2005). For the crystal structure of hypoxanthinium nitrate monohydrate as an example of an oxopurine compound, see: Schmalle et al. (1990). For graph-set analysis of hydrogen bonds, see: Etter et al. (1990); Bernstein et al. (1995). For puckering analysis, see: Cremer & Pople (1975). For general information about the chelate effect in coordination chemistry, see: Gade (1998).

Experimental top

The title compound was prepared by reacting 6-amino-1,3-dimethyl-5-[(E)- 2-(hydroxy)benzylideneamino]pyrimidine-2,4-(1H,3H)-dione and NH₄VO₃ in methanol. A bright yellow precipitate was filtered, washed with methanol and dried under reduced pressure. Single-crystals suitable for the X-ray diffraction study were obtained by recrystallization from ethanol-dichlormethane (v:v = 1:1) mixture which was left in a fridge for several days.

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

	Fig. 1. The molecular structure of the title compound, with atom labels and anisotropic displacement ellipsoids (drawn at 50% probability level).
	Fig. 2. Intermolecular contacts, viewed along [-1 0 0]. Symmetry operators: ⁱ -x + 2, -y - 1, -z; ⁱⁱ -x + 1, -y + 1, -z.
	Fig. 3. Molecular packing of the title compound, viewed along [0 1 0] (anisotropic displacement ellipsoids drawn at 50% probability level).

8-(2-Hydroxyphenyl)-1,3-dimethyl-1H-purine-2,6(3H,7H)- dione top

Crystal data top

C₁₃H₁₂N₄O₃	F(000) = 568
M_r = 272.27	D_x = 1.502 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1955 reflections
a = 8.6418 (5) Å	θ = 2.4–27.2°
b = 5.9415 (3) Å	µ = 0.11 mm⁻¹
c = 23.4475 (10) Å	T = 200 K
β = 91.275 (2)°	Platelet, yellow
V = 1203.62 (11) Å³	0.41 × 0.10 × 0.05 mm
Z = 4

Data collection top

Bruker APEXII CCD diffractometer	2975 independent reflections
Radiation source: fine-focus sealed tube	1752 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.043
ϕ and ω scans	θ_max = 28.3°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −11→11
T_min = 0.860, T_max = 1.000	k = −7→6
10068 measured reflections	l = −31→27

Refinement top

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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.124	H atoms treated by a mixture of independent and constrained refinement
S = 1.01	w = 1/[σ²(F_o²) + (0.0584P)² + 0.0815P] where P = (F_o² + 2F_c²)/3
2975 reflections	(Δ/σ)_max < 0.001
188 parameters	Δρ_max = 0.25 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₁₃H₁₂N₄O₃	V = 1203.62 (11) Å³
M_r = 272.27	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.6418 (5) Å	µ = 0.11 mm⁻¹
b = 5.9415 (3) Å	T = 200 K
c = 23.4475 (10) Å	0.41 × 0.10 × 0.05 mm
β = 91.275 (2)°

Data collection top

Bruker APEXII CCD diffractometer	2975 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2008)	1752 reflections with I > 2σ(I)
T_min = 0.860, T_max = 1.000	R_int = 0.043
10068 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.049	0 restraints
wR(F²) = 0.124	H atoms treated by a mixture of independent and constrained refinement
S = 1.01	Δρ_max = 0.25 e Å⁻³
2975 reflections	Δρ_min = −0.21 e Å⁻³
188 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.47991 (16)	0.4606 (2)	0.07866 (5)	0.0356 (4)
O2	0.66823 (16)	−0.0720 (2)	0.20267 (6)	0.0390 (4)
O3	0.94790 (18)	−0.3204 (3)	−0.06725 (6)	0.0454 (4)
H3	0.9105	−0.2923	−0.0353	0.068*
N1	0.65931 (17)	0.2091 (3)	−0.01367 (6)	0.0260 (4)
H71	0.615 (2)	0.330 (4)	−0.0365 (9)	0.049 (7)*
N2	0.79184 (18)	−0.1028 (3)	0.00928 (6)	0.0273 (4)
N3	0.73063 (17)	−0.1106 (3)	0.10978 (6)	0.0269 (4)
N4	0.57335 (17)	0.1913 (3)	0.13977 (6)	0.0259 (4)
C1	0.6392 (2)	0.1685 (3)	0.04385 (7)	0.0247 (4)
C2	0.7221 (2)	−0.0211 (3)	0.05591 (7)	0.0238 (4)
C3	0.6584 (2)	−0.0024 (3)	0.15408 (8)	0.0267 (4)
C4	0.5573 (2)	0.2871 (3)	0.08562 (7)	0.0254 (4)
C5	0.8231 (2)	−0.3115 (3)	0.12198 (8)	0.0323 (5)
H5A	0.8296	−0.4032	0.0874	0.048*
H5B	0.7742	−0.3993	0.1520	0.048*
H5C	0.9274	−0.2668	0.1347	0.048*
C6	0.4923 (2)	0.3034 (4)	0.18658 (8)	0.0342 (5)
H6A	0.5389	0.4513	0.1938	0.051*
H6B	0.5012	0.2112	0.2212	0.051*
H6C	0.3827	0.3221	0.1759	0.051*
C7	0.7514 (2)	0.0418 (3)	−0.03268 (8)	0.0254 (4)
C8	0.8012 (2)	0.0162 (3)	−0.09136 (8)	0.0258 (4)
C9	0.7563 (2)	0.1677 (3)	−0.13407 (8)	0.0307 (5)
H9	0.6913	0.2908	−0.1248	0.037*
C10	0.8043 (2)	0.1426 (4)	−0.18967 (8)	0.0352 (5)
H10	0.7732	0.2476	−0.2182	0.042*
C11	0.8985 (2)	−0.0377 (4)	−0.20303 (8)	0.0383 (5)
H11	0.9316	−0.0568	−0.2411	0.046*
C12	0.9443 (2)	−0.1892 (4)	−0.16178 (8)	0.0391 (5)
H12	1.0093	−0.3115	−0.1716	0.047*
C13	0.8968 (2)	−0.1664 (3)	−0.10562 (8)	0.0316 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0444 (8)	0.0353 (8)	0.0272 (8)	0.0189 (7)	0.0052 (6)	0.0019 (6)
O2	0.0474 (9)	0.0435 (9)	0.0265 (8)	0.0104 (7)	0.0069 (6)	0.0106 (7)
O3	0.0634 (10)	0.0420 (10)	0.0311 (8)	0.0278 (8)	0.0109 (7)	0.0036 (7)
N1	0.0290 (9)	0.0272 (9)	0.0219 (8)	0.0080 (7)	0.0029 (6)	0.0010 (7)
N2	0.0320 (9)	0.0256 (9)	0.0245 (8)	0.0059 (7)	0.0016 (7)	−0.0002 (7)
N3	0.0296 (9)	0.0270 (9)	0.0240 (8)	0.0059 (7)	0.0022 (6)	0.0037 (7)
N4	0.0284 (8)	0.0283 (9)	0.0212 (8)	0.0062 (7)	0.0047 (6)	0.0010 (7)
C1	0.0278 (10)	0.0251 (10)	0.0212 (9)	0.0041 (8)	0.0024 (7)	0.0008 (8)
C2	0.0248 (9)	0.0243 (10)	0.0224 (9)	0.0006 (8)	0.0029 (7)	−0.0011 (8)
C3	0.0261 (10)	0.0269 (11)	0.0270 (10)	0.0011 (8)	0.0028 (8)	0.0032 (8)
C4	0.0252 (10)	0.0270 (11)	0.0241 (10)	0.0034 (9)	0.0015 (8)	0.0006 (8)
C5	0.0356 (11)	0.0274 (11)	0.0339 (11)	0.0090 (9)	0.0015 (8)	0.0052 (9)
C6	0.0396 (11)	0.0399 (13)	0.0233 (10)	0.0084 (10)	0.0088 (8)	0.0003 (9)
C7	0.0246 (10)	0.0257 (10)	0.0257 (10)	0.0038 (8)	0.0012 (7)	−0.0019 (8)
C8	0.0274 (10)	0.0282 (10)	0.0219 (9)	0.0036 (8)	0.0031 (7)	−0.0025 (8)
C9	0.0309 (10)	0.0341 (12)	0.0271 (10)	0.0063 (9)	0.0028 (8)	−0.0014 (9)
C10	0.0370 (11)	0.0425 (13)	0.0261 (10)	0.0046 (10)	0.0019 (9)	0.0018 (10)
C11	0.0439 (12)	0.0475 (14)	0.0239 (11)	0.0060 (11)	0.0067 (9)	−0.0053 (10)
C12	0.0458 (13)	0.0388 (13)	0.0330 (12)	0.0124 (11)	0.0090 (9)	−0.0070 (10)
C13	0.0352 (11)	0.0308 (11)	0.0289 (11)	0.0058 (9)	0.0026 (8)	−0.0012 (9)

Geometric parameters (Å, º) top

O1—C4	1.237 (2)	C5—H5A	0.9800
O2—C3	1.213 (2)	C5—H5B	0.9800
O3—C13	1.351 (2)	C5—H5C	0.9800
O3—H3	0.8400	C6—H6A	0.9800
N1—C7	1.355 (2)	C6—H6B	0.9800
N1—C1	1.385 (2)	C6—H6C	0.9800
N1—H71	0.97 (2)	C7—C8	1.459 (2)
N2—C7	1.346 (2)	C8—C9	1.395 (3)
N2—C2	1.351 (2)	C8—C13	1.409 (3)
N3—C2	1.371 (2)	C9—C10	1.385 (3)
N3—C3	1.382 (2)	C9—H9	0.9500
N3—C5	1.461 (2)	C10—C11	1.385 (3)
N4—C4	1.396 (2)	C10—H10	0.9500
N4—C3	1.402 (2)	C11—C12	1.373 (3)
N4—C6	1.474 (2)	C11—H11	0.9500
C1—C2	1.361 (3)	C12—C13	1.394 (3)
C1—C4	1.410 (3)	C12—H12	0.9500

C13—O3—H3	109.5	H5B—C5—H5C	109.5
C7—N1—C1	106.25 (15)	N4—C6—H6A	109.5
C7—N1—H71	126.1 (13)	N4—C6—H6B	109.5
C1—N1—H71	127.6 (13)	H6A—C6—H6B	109.5
C7—N2—C2	104.41 (15)	N4—C6—H6C	109.5
C2—N3—C3	119.72 (16)	H6A—C6—H6C	109.5
C2—N3—C5	121.03 (15)	H6B—C6—H6C	109.5
C3—N3—C5	119.14 (15)	N2—C7—N1	111.87 (15)
C4—N4—C3	126.42 (15)	N2—C7—C8	123.05 (16)
C4—N4—C6	116.97 (15)	N1—C7—C8	125.08 (16)
C3—N4—C6	116.61 (15)	C9—C8—C13	118.81 (17)
C2—C1—N1	105.66 (16)	C9—C8—C7	121.77 (17)
C2—C1—C4	122.63 (17)	C13—C8—C7	119.42 (17)
N1—C1—C4	131.69 (17)	C10—C9—C8	121.44 (18)
N2—C2—C1	111.80 (16)	C10—C9—H9	119.3
N2—C2—N3	126.19 (17)	C8—C9—H9	119.3
C1—C2—N3	122.00 (16)	C9—C10—C11	119.09 (19)
O2—C3—N3	121.57 (17)	C9—C10—H10	120.5
O2—C3—N4	122.01 (17)	C11—C10—H10	120.5
N3—C3—N4	116.43 (16)	C12—C11—C10	120.61 (18)
O1—C4—N4	120.16 (16)	C12—C11—H11	119.7
O1—C4—C1	127.08 (17)	C10—C11—H11	119.7
N4—C4—C1	112.74 (16)	C11—C12—C13	121.01 (19)
N3—C5—H5A	109.5	C11—C12—H12	119.5
N3—C5—H5B	109.5	C13—C12—H12	119.5
H5A—C5—H5B	109.5	O3—C13—C12	117.67 (18)
N3—C5—H5C	109.5	O3—C13—C8	123.27 (17)
H5A—C5—H5C	109.5	C12—C13—C8	119.05 (18)

C7—N1—C1—C2	0.44 (19)	C2—C1—C4—O1	179.62 (19)
C7—N1—C1—C4	179.0 (2)	N1—C1—C4—O1	1.2 (3)
C7—N2—C2—C1	0.3 (2)	C2—C1—C4—N4	1.1 (3)
C7—N2—C2—N3	−179.25 (17)	N1—C1—C4—N4	−177.26 (18)
N1—C1—C2—N2	−0.5 (2)	C2—N2—C7—N1	0.0 (2)
C4—C1—C2—N2	−179.25 (17)	C2—N2—C7—C8	−179.54 (17)
N1—C1—C2—N3	179.11 (16)	C1—N1—C7—N2	−0.3 (2)
C4—C1—C2—N3	0.4 (3)	C1—N1—C7—C8	179.23 (17)
C3—N3—C2—N2	177.08 (17)	N2—C7—C8—C9	179.44 (17)
C5—N3—C2—N2	0.9 (3)	N1—C7—C8—C9	0.0 (3)
C3—N3—C2—C1	−2.5 (3)	N2—C7—C8—C13	−0.4 (3)
C5—N3—C2—C1	−178.64 (17)	N1—C7—C8—C13	−179.78 (18)
C2—N3—C3—O2	−177.22 (18)	C13—C8—C9—C10	−0.4 (3)
C5—N3—C3—O2	−1.0 (3)	C7—C8—C9—C10	179.85 (18)
C2—N3—C3—N4	2.8 (2)	C8—C9—C10—C11	0.3 (3)
C5—N3—C3—N4	179.07 (16)	C9—C10—C11—C12	−0.3 (3)
C4—N4—C3—O2	178.72 (17)	C10—C11—C12—C13	0.3 (3)
C6—N4—C3—O2	−1.7 (3)	C11—C12—C13—O3	−179.3 (2)
C4—N4—C3—N3	−1.3 (3)	C11—C12—C13—C8	−0.4 (3)
C6—N4—C3—N3	178.23 (16)	C9—C8—C13—O3	179.20 (18)
C3—N4—C4—O1	−179.24 (17)	C7—C8—C13—O3	−1.0 (3)
C6—N4—C4—O1	1.2 (3)	C9—C8—C13—C12	0.4 (3)
C3—N4—C4—C1	−0.6 (3)	C7—C8—C13—C12	−179.82 (18)
C6—N4—C4—C1	179.82 (16)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···N2	0.84	1.86	2.611 (2)	148
N1—H71···O1ⁱ	0.97 (2)	1.78 (2)	2.746 (2)	175.4 (19)
C9—H9···O1ⁱ	0.95	2.37	3.294 (2)	164
C5—H5A···O3ⁱⁱ	0.98	2.58	3.234 (2)	124

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

Experimental details

Crystal data
Chemical formula	C₁₃H₁₂N₄O₃
M_r	272.27
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	200
a, b, c (Å)	8.6418 (5), 5.9415 (3), 23.4475 (10)
β (°)	91.275 (2)
V (Å³)	1203.62 (11)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.11
Crystal size (mm)	0.41 × 0.10 × 0.05

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2008)
T_min, T_max	0.860, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	10068, 2975, 1752
R_int	0.043
(sin θ/λ)_max (Å⁻¹)	0.667

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.124, 1.01
No. of reflections	2975
No. of parameters	188
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.21

Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···N2	0.84	1.86	2.611 (2)	148.2
N1—H71···O1ⁱ	0.97 (2)	1.78 (2)	2.746 (2)	175.4 (19)
C9—H9···O1ⁱ	0.95	2.37	3.294 (2)	164.3
C5—H5A···O3ⁱⁱ	0.98	2.58	3.234 (2)	124.2

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

Acknowledgements

The authors thank Mrs Patricia Pono for helpful discussions.

References

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