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Cocrystallization of baicalein with nicotinamide yields a 1:1 cocrystal [systematic name: pyridine-3-carboxamide-5,6,7-trihy­droxy-2-phenyl-4H-chromen-4-one (1/1)], C6H6N2O·C15H10O5. The asymmetric unit contains one baicalein and one nicotinamide mol­ecule, both in neutral forms. Mol­ecules in the cocrystal form column motifs stabilized by an array of inter­molecular hydrogen bonds.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270112024456/fg3251sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270112024456/fg3251Isup2.hkl
Contains datablock I

cml

Chemical Markup Language (CML) file https://doi.org/10.1107/S0108270112024456/fg3251Isup3.cml
Supplementary material

CCDC reference: 893495

Comment top

Flavones, members of the flavonoid family, are low molecular weight plant polyphenolic compounds with a wide range of biological activities (Verma & Pratap, 2010). Baicalein (5,6,7-trihydroxyflavone) is one of the main bioactive compounds found in roots of the traditional Chinese herb Scutellaria baicalensis (Olennikov et al., 2010), and has been shown to inhibit iron-induced lipid peroxidation (Perez et al., 2009) and induce apoptosis in HIV-infected cells in vitro (Ono et al., 1989), and research into its anticancer (Miocinovic et al., 2005), antioxidant (Shao et al., 2002) and anti-inflamatory (Chou et al., 2003) properties shows good results.

By virtue of the fact that flavonoids (including baicalein) have low solubility in water and therefore low bioavailability (Zhang et al., 2005, 2007), the discovery and identification of their new solid forms is highly desirable. A convenient way of modifying the physicochemical properties and pharmacokinetic parameters of active compounds of pharmaceutical interest (active pharmaceutical ingredients, APIs) is cocrystallization with a substance generally regarded as safe (GRAS) (Schultheiss & Newman, 2009, and references therein). This gives rise to novel supramolecular complexes which generally exhibit enhanced solubility and dissolution rates compared with their constituent components. Recently, the structures of quercetin cocrystals with caffeine (MeOH solvate; Smith et al., 2011), isonicotinamide (Smith et al., 2011) and theobromine [dihydrate; Cambridge Structural Database (CSD; Allen, 2002) refcode MUPPOD (Clarke et al., 2010)] have been determined, and their solubility and oral bioavailability have been shown to be improved over that of quercetin (Smith et al., 2011).

Nicotinamide (NA) belongs to the vitamin B group (vitamin B3) and is classified as a GRAS substance. Therefore, this molecule is widely used in the cocrystallization of carboxylic acid functionalized APIs (Berry et al., 2008). Recently, two cocrystals of orcinol (3,5-dihydroxytoluene) with NA were reported (CSD refcodes EWAQEZ and EWAQAV; Mukherjee et al., 2011), showing that NA can be successfully applied to the cocrystallization of hydroxy-functionalized APIs.

Herein, the title 1:1 cocrystal of baicalein with nicotinamide, (I), is reported. The asymmetric unit of (I) comprises one baicalein and one nicotinamide molecule, both in their neutral forms (Fig. 1).

It is common among flavones that two rings of the phenylbenzopyran entity, referred to as A/C (benzopyran), are conjugated and coplanar, while the third one, B (phenyl), is usually out of this plane. In (I), the mean planes defined by the A/C and B rings of baicalein are inclined to each other with a dihedral angle of 20.0 (2)°. This is higher than the values of 8.6 and 9.7° determined for baicalein crystals grown from, respectively, a methanol–water mixture (CSD refcode RAMGOB; Rossi et al., 2001) and ethyl acetate (CSD refcode RAMGOB01; Hibbs et al., 2003). Typically, the cocrystallization of flavonoids leads to a change in the angle between the A/C and B ring planes. This can be illustrated by comparing the values of the above-mentioned angles in quercetin–caffeine methanol solvate (Smith et al., 2011) and quercetin–isonicotinamide (Smith et al., 2011) cocrystals (0.2 and 24.0°, respectively) with the values of 8.1 and 22.0°, respectively, for quercetin dihydrate (CSD refcode FEFBEX01; Jin et al., 1990) and quercetin pyridine solvate (CSD refcode NIXLUC; O'Mahony et al., 2006).

The overall geometry of baicalein and NA in (I) is similar to that determined for the parent components. A twist of the amide group of NA relative to its pyridine ring plane is reflected in the value of the O1A—C7A—C3A—C4A torsion angle [-28.2 (5)°, Table 1] and reveals a similar conformation to that of a pure nicotinamide crystal (CSD refcode NICOAM01; Miwa et al., 1999).

The supramolecular arrangement in flavonoid cocrystals depends on the number of hydroxyl substituents on the flavonoid backbone, as well as on the reaction conditions (Timmons et al., 2008). Quercetin, hesperetin and apigenin exhibit hydroxy substitution on both benzopyran and phenyl rings, which facilitates the formation of O—H···O and N—H···O hydrogen-bonded two- or three-dimensional structures. Accordingly, quercetin cocrystals with caffeine (MeOH solvate; Smith et al., 2011), isonicotinamide (Smith et al., 2011), theobromine (dihydrate; CSD refcode MUPPOD; Clarke et al., 2010) and triethylenediamine (CSD refcode COLHIV; Timmons et al., 2008) reveal two-dimensional hydrogen-bonded networks, and a three-dimensional network has been observed in the quercetin–isonicotinic acid zwitterion hydrate cocrystal (CSD refcode RUWHUN; Kavuru et al., 2010). Similarly, the hesperetin–isonicotinamide cocrystal (Kavuru, 2008) comprises molecules arranged into a two-dimensional sheet, while hesperetin–nicotinic acid zwitterion cocrystals (CSD refcodes RUWHEX and RUWHIB; Kavuru et al., 2010) and the apigein triethyelenediamine cocrystal (Timmons et al., 2008) reveal the formation of one-dimensional extended structures.

Baicalein contains a trihydroxy-substituted benzopyran ring, therefore having three potential hydrogen-bond donor atoms (O5, O6 and O7). In the crystal structure of (I), hydroxy atom O5 of one baicalein molecule acts as an H-atom donor in an intramolecular O5—H5···O4 hydrogen bond, which is common to all 5-hydroxyflavone derivatives known so far. The remaining atoms O6 and O7 act as H-atom donors in intermolecular interactions (Table 2). Each baicalein molecule is also joined to two adjacent inversion-related nicotniamide molecules, which leaves no possibility for further extension into a two-dimensional structure. Similarly, 3,6-dihydroxyflavone possesses two potential hydrogen-bond donor atoms on the benzopyran ring (O3 and O6), facilitating the formation of one-dimensional helices or ribbons with a bidentate cocrystal former (CSD refcodes COLHAN and COLHIV, respectively; Timmons et al., 2008).

An O7—H7···O1A intermolecular hydrogen bond forms a baicalein–NA heterodimer (Figs. 1 and 2a, Table 2), in which the planes defined by the A/C rings of baicalein and the N1A/C6A atoms of NA are inclined to each other with a dihedral angle of 27.3 (2)°. The heterodimers are further extended along the a direction into ribbons through N2A—H2A2···O1Aii hydrogen bonds (Fig. 2a). Two inversion-related ribbons are assembled into a one-dimensional column in the a direction by means of O6—H6···N1Ai hydrogen bonds (Fig. 2b). C4A—H4A···O4iii interactions join adjacent columns into sheets parallel to (001) (Table 2). Other possible N—H···O and C—H···O contacts with angles significantly below 140° are regarded as structurally insignificant (Wood et al., 2009).

It should be noted here that the O—H···Nar interaction is one of the most competitive heterosynthons (Bis et al., 2007), based on a search of the CSD (Version? No. of hits?), and has also been observed in quercetin–isonicotinamide (Smith et al., 2011), hesperetin–isonicotinamide (Kavuru, 2008) and quercetin–caffeine methanol solvate (Smith et al., 2011) cocrystals, as well as in the cocrystal of orcinol (3,5-dihydroxytoluene) with nicotinamide (CSD refcodes EWAQEZ and EWAQAV; Mukherjee et al., 2011).

In summary, this report provides an insight into the previously unexplored field of baicalein cocrystallization and is a further example of the successful application of nicotinamide as a coocrystal former for hydroxy-substituted molecules. The crystal of (I) comprises one-dimensional ribbons, which are assembled into columns and held together in the crystal structure by weak intermolecular C—H···O interactions. In contrast with the quercetin, hesperetin and apigenin cocrystals known so far, the crystal structure of (I) does not exhibit homomolecular hydrogen-bonded dimers.

Related literature top

For related literature, see: Allen (2002); Berry et al. (2008); Bis et al. (2007); Chou et al. (2003); Clarke et al. (2010); Hibbs et al. (2003); Jin et al. (1990); Kavuru (2008); Kavuru et al. (2010); Miocinovic et al. (2005); Miwa et al. (1999); Mukherjee et al. (2011); O'Mahony et al. (2006); Olennikov et al. (2010); Ono et al. (1989); Perez et al. (2009); Rossi et al. (2001); Schultheiss & Newman (2009); Shao et al. (2002); Smith et al. (2011); Timmons et al. (2008); Verma & Pratap (2010); Wood et al. (2009); Zhang et al. (2005, 2007).

Experimental top

Baicalein was obtained from Sino-Future Bio-Tech Co. Ltd, nicotinamide was obtained from Sigma–Aldrich and both were used without further purification. Baicalein (0.025 g, 0.181 mmol) was dissolved in a close to saturated solution of nicotinamide in ethyl acetate (10 ml). Slow evaporation of the resulting solution yielded amorphous material and crystals of (I). The latter were separated manually (?) and recrystallized from which solvent?

Refinement top

All H atoms were found in difference Fourier maps, but in the final refinement cycles they were repositioned in their calculated positions and refined using a riding model, with C—H = 0.95 Å, N—H = 0.88 Å and O—H = 0.84 Å, and with Uiso(H) = 1.2Ueq(C,N) or 1.5Ueq(O).

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2009); cell refinement: CrysAlis RED (Oxford Diffraction, 2009); data reduction: CrysAlis RED (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular complex of (I), showing the atom-numbering scheme and the symmetry-independent hydrogen bonds (dashed lines). Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. A packing diagram for (I), showing (a) ribbons of (I) along the a axis and (b) the inter-ribbon hydrogen-bond network resulting in the column motif along the a axis. In the electronic version of the journal, hydrogen bonds between molecules forming the heteromolecular dimer are indicated by blue dashed lines, and red and green dashed lines, respectively, represent hydrogen bonds involved in forming the ribbon and column motifs. Some H atoms and intramolecular hydrogen bonds have been omitted for clarity. [Symmetry codes: (i) -x + 2, -y + 2, -z + 1; (ii) x + 1, y, z; (#) x - 1, y, z.]
pyridine-3-carboxamide–5,6,7-trihydroxy-2-phenyl-4H-chromen-4-one (1/1) top
Crystal data top
C6H6N2·C15H10O5Z = 2
Mr = 392.36F(000) = 408
Triclinic, P1Dx = 1.495 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 5.248 (2) ÅCell parameters from 3736 reflections
b = 11.422 (3) Åθ = 3.2–28.0°
c = 14.952 (4) ŵ = 0.11 mm1
α = 84.38 (3)°T = 100 K
β = 82.29 (3)°Plate, yellow
γ = 79.83 (3)°0.48 × 0.07 × 0.04 mm
V = 871.7 (5) Å3
Data collection top
Kuma KM-4-CCD κ-geometry
diffractometer with a Sapphire2 CCD area detector
3432 independent reflections
Radiation source: Enhance (Mo) X-ray Source2076 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.065
ω scansθmax = 26.0°, θmin = 3.2°
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2009)
h = 66
Tmin = 0.739, Tmax = 1.000k = 1414
11110 measured reflectionsl = 1817
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.058Hydrogen site location: difference Fourier map
wR(F2) = 0.181H-atom parameters constrained
S = 1.08 w = 1/[σ2(Fo2) + (0.0899P)2 + 0.1803P]
where P = (Fo2 + 2Fc2)/3
3432 reflections(Δ/σ)max < 0.001
265 parametersΔρmax = 0.26 e Å3
0 restraintsΔρmin = 0.27 e Å3
Crystal data top
C6H6N2·C15H10O5γ = 79.83 (3)°
Mr = 392.36V = 871.7 (5) Å3
Triclinic, P1Z = 2
a = 5.248 (2) ÅMo Kα radiation
b = 11.422 (3) ŵ = 0.11 mm1
c = 14.952 (4) ÅT = 100 K
α = 84.38 (3)°0.48 × 0.07 × 0.04 mm
β = 82.29 (3)°
Data collection top
Kuma KM-4-CCD κ-geometry
diffractometer with a Sapphire2 CCD area detector
3432 independent reflections
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2009)
2076 reflections with I > 2σ(I)
Tmin = 0.739, Tmax = 1.000Rint = 0.065
11110 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0580 restraints
wR(F2) = 0.181H-atom parameters constrained
S = 1.08Δρmax = 0.26 e Å3
3432 reflectionsΔρmin = 0.27 e Å3
265 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
O10.4177 (4)0.4855 (2)0.15008 (15)0.0244 (6)
O41.0197 (4)0.3361 (2)0.29500 (16)0.0246 (6)
O51.0425 (4)0.5428 (2)0.34338 (16)0.0261 (6)
H51.07480.46820.34290.039*
O60.8561 (4)0.7897 (2)0.32489 (16)0.0262 (6)
H60.94480.75440.36530.039*
O70.4514 (4)0.8715 (2)0.22918 (17)0.0274 (6)
H70.50420.90390.26970.041*
C20.5075 (6)0.3658 (3)0.1531 (2)0.0224 (7)
C30.7086 (6)0.3141 (3)0.1999 (2)0.0225 (7)
H30.76660.23050.19910.027*
C40.8349 (6)0.3822 (3)0.2500 (2)0.0226 (8)
C50.8494 (6)0.5873 (3)0.2906 (2)0.0207 (7)
C60.7594 (6)0.7089 (3)0.2843 (2)0.0213 (7)
C70.5489 (6)0.7527 (3)0.2342 (2)0.0205 (7)
C80.4365 (6)0.6782 (3)0.1899 (2)0.0228 (8)
H80.29520.70950.15630.027*
C90.5326 (6)0.5577 (3)0.1953 (2)0.0205 (7)
C100.7404 (6)0.5093 (3)0.2459 (2)0.0207 (7)
C110.3676 (6)0.3028 (3)0.0992 (2)0.0231 (8)
C120.2290 (6)0.3637 (3)0.0315 (2)0.0271 (8)
H120.22310.44730.01950.033*
C130.0982 (7)0.3026 (3)0.0191 (3)0.0313 (9)
H130.00210.34490.06510.038*
C140.1074 (7)0.1812 (4)0.0027 (3)0.0333 (9)
H140.01960.13990.03790.040*
C150.2440 (7)0.1196 (3)0.0648 (3)0.0344 (9)
H150.24890.03590.07620.041*
C160.3745 (7)0.1793 (3)0.1162 (3)0.0299 (8)
H160.46800.13670.16270.036*
O1A0.5370 (4)1.0390 (2)0.33402 (17)0.0278 (6)
N1A0.8340 (5)1.2568 (2)0.54180 (19)0.0239 (7)
N2A0.9740 (5)1.0264 (3)0.3285 (2)0.0265 (7)
H2A11.00530.97090.28970.032*
H2A21.10441.05200.34750.032*
C2A0.8664 (6)1.1724 (3)0.4837 (2)0.0238 (8)
H2A1.01771.11280.48350.029*
C3A0.6898 (6)1.1672 (3)0.4234 (2)0.0214 (7)
C4A0.4661 (6)1.2525 (3)0.4250 (2)0.0237 (8)
H4A0.33821.24980.38620.028*
C5A0.4324 (6)1.3411 (3)0.4837 (2)0.0239 (8)
H5A0.28251.40160.48540.029*
C6A0.6213 (6)1.3402 (3)0.5401 (2)0.0241 (8)
H6A0.59851.40240.57970.029*
C7A0.7286 (6)1.0716 (3)0.3585 (2)0.0211 (7)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0194 (12)0.0266 (13)0.0301 (14)0.0052 (10)0.0085 (10)0.0054 (11)
O40.0174 (11)0.0267 (13)0.0319 (14)0.0046 (10)0.0105 (10)0.0015 (11)
O50.0201 (12)0.0261 (13)0.0350 (15)0.0036 (10)0.0137 (10)0.0034 (12)
O60.0242 (13)0.0263 (13)0.0319 (15)0.0068 (10)0.0134 (10)0.0022 (11)
O70.0242 (13)0.0258 (13)0.0363 (15)0.0046 (10)0.0140 (11)0.0078 (11)
C20.0181 (16)0.0244 (18)0.0263 (19)0.0046 (13)0.0040 (14)0.0056 (15)
C30.0174 (16)0.0243 (18)0.0271 (19)0.0052 (13)0.0027 (14)0.0049 (15)
C40.0125 (15)0.0296 (19)0.0252 (19)0.0052 (14)0.0001 (14)0.0001 (15)
C50.0144 (15)0.0269 (18)0.0220 (18)0.0046 (13)0.0060 (13)0.0006 (15)
C60.0164 (16)0.0253 (18)0.0249 (19)0.0078 (13)0.0052 (14)0.0030 (15)
C70.0177 (16)0.0189 (17)0.0250 (18)0.0034 (13)0.0020 (13)0.0025 (14)
C80.0156 (16)0.0291 (19)0.0250 (19)0.0036 (14)0.0074 (14)0.0022 (15)
C90.0147 (15)0.0264 (18)0.0231 (18)0.0066 (13)0.0053 (13)0.0060 (15)
C100.0135 (15)0.0254 (18)0.0248 (18)0.0049 (13)0.0058 (13)0.0015 (15)
C110.0143 (16)0.0293 (19)0.0261 (19)0.0043 (13)0.0004 (14)0.0059 (15)
C120.0228 (17)0.0302 (19)0.031 (2)0.0087 (15)0.0083 (15)0.0025 (16)
C130.0286 (19)0.038 (2)0.030 (2)0.0096 (16)0.0103 (16)0.0039 (17)
C140.031 (2)0.042 (2)0.034 (2)0.0128 (17)0.0105 (16)0.0119 (18)
C150.037 (2)0.0255 (19)0.046 (2)0.0110 (16)0.0115 (18)0.0076 (18)
C160.0241 (18)0.033 (2)0.036 (2)0.0057 (15)0.0118 (16)0.0040 (17)
O1A0.0163 (11)0.0303 (13)0.0398 (15)0.0023 (10)0.0118 (10)0.0092 (12)
N1A0.0188 (14)0.0272 (16)0.0281 (16)0.0073 (12)0.0052 (12)0.0049 (13)
N2A0.0193 (14)0.0286 (16)0.0347 (18)0.0058 (12)0.0059 (13)0.0104 (14)
C2A0.0174 (16)0.0224 (18)0.033 (2)0.0033 (13)0.0068 (14)0.0028 (16)
C3A0.0168 (16)0.0218 (17)0.0276 (19)0.0071 (13)0.0053 (14)0.0023 (15)
C4A0.0171 (16)0.0269 (19)0.0292 (19)0.0065 (14)0.0077 (14)0.0000 (16)
C5A0.0185 (16)0.0213 (18)0.033 (2)0.0041 (13)0.0035 (14)0.0051 (15)
C6A0.0195 (17)0.0261 (18)0.0290 (19)0.0106 (14)0.0010 (14)0.0036 (15)
C7A0.0162 (16)0.0226 (17)0.0255 (18)0.0049 (13)0.0056 (13)0.0002 (14)
Geometric parameters (Å, º) top
O1—C21.364 (4)C12—H120.95
O1—C91.376 (4)C13—C141.378 (5)
O4—C41.263 (4)C13—H130.95
O5—C51.365 (4)C14—C151.381 (5)
O5—H50.84C14—H140.95
O6—C61.355 (4)C15—C161.391 (5)
O6—H60.84C15—H150.95
O7—C71.362 (4)C16—H160.95
O7—H70.84O1A—C7A1.242 (4)
C2—C31.359 (5)N1A—C2A1.334 (4)
C2—C111.472 (5)N1A—C6A1.335 (4)
C3—C41.427 (5)N2A—C7A1.335 (4)
C3—H30.95N2A—H2A10.88
C4—C101.447 (5)N2A—H2A20.88
C5—C61.384 (5)C2A—C3A1.388 (4)
C5—C101.401 (5)C2A—H2A0.95
C6—C71.408 (4)C3A—C4A1.386 (4)
C7—C81.379 (5)C3A—C7A1.500 (5)
C8—C91.378 (5)C4A—C5A1.378 (5)
C8—H80.95C4A—H4A0.95
C9—C101.412 (4)C5A—C6A1.383 (5)
C11—C121.385 (5)C5A—H5A0.95
C11—C161.404 (5)C6A—H6A0.95
C12—C131.393 (5)
C2—O1—C9119.7 (2)C13—C12—H12119.9
C5—O5—H5109.5C14—C13—C12120.4 (3)
C6—O6—H6109.5C14—C13—H13119.8
C7—O7—H7109.5C12—C13—H13119.8
C3—C2—O1122.2 (3)C13—C14—C15120.0 (3)
C3—C2—C11125.3 (3)C13—C14—H14120.0
O1—C2—C11112.5 (3)C15—C14—H14120.0
C2—C3—C4121.6 (3)C14—C15—C16120.3 (3)
C2—C3—H3119.2C14—C15—H15119.8
C4—C3—H3119.2C16—C15—H15119.8
O4—C4—C3122.9 (3)C15—C16—C11119.8 (3)
O4—C4—C10121.2 (3)C15—C16—H16120.1
C3—C4—C10115.9 (3)C11—C16—H16120.1
O5—C5—C6119.1 (3)C2A—N1A—C6A117.3 (3)
O5—C5—C10119.8 (3)C7A—N2A—H2A1120.0
C6—C5—C10121.1 (3)C7A—N2A—H2A2120.0
O6—C6—C5124.5 (3)H2A1—N2A—H2A2120.0
O6—C6—C7117.0 (3)N1A—C2A—C3A123.3 (3)
C5—C6—C7118.5 (3)N1A—C2A—H2A118.4
O7—C7—C8118.5 (3)C3A—C2A—H2A118.4
O7—C7—C6119.7 (3)C4A—C3A—C2A118.4 (3)
C8—C7—C6121.8 (3)C4A—C3A—C7A118.9 (3)
C9—C8—C7118.9 (3)C2A—C3A—C7A122.7 (3)
C9—C8—H8120.5C5A—C4A—C3A118.8 (3)
C7—C8—H8120.5C5A—C4A—H4A120.6
O1—C9—C8117.8 (3)C3A—C4A—H4A120.6
O1—C9—C10120.9 (3)C4A—C5A—C6A118.6 (3)
C8—C9—C10121.4 (3)C4A—C5A—H5A120.7
C5—C10—C9118.3 (3)C6A—C5A—H5A120.7
C5—C10—C4122.1 (3)N1A—C6A—C5A123.5 (3)
C9—C10—C4119.6 (3)N1A—C6A—H6A118.2
C12—C11—C16119.3 (3)C5A—C6A—H6A118.2
C12—C11—C2120.9 (3)O1A—C7A—N2A122.8 (3)
C16—C11—C2119.7 (3)O1A—C7A—C3A120.1 (3)
C11—C12—C13120.2 (3)N2A—C7A—C3A117.1 (3)
C11—C12—H12119.9
C9—O1—C2—C30.2 (5)O4—C4—C10—C50.5 (5)
C9—O1—C2—C11178.4 (3)C3—C4—C10—C5178.9 (3)
O1—C2—C3—C41.1 (5)O4—C4—C10—C9179.7 (3)
C11—C2—C3—C4179.5 (3)C3—C4—C10—C90.9 (4)
C2—C3—C4—O4179.0 (3)C3—C2—C11—C12158.5 (3)
C2—C3—C4—C101.6 (5)O1—C2—C11—C1220.0 (4)
O5—C5—C6—O62.4 (5)C3—C2—C11—C1621.4 (5)
C10—C5—C6—O6179.5 (3)O1—C2—C11—C16160.1 (3)
O5—C5—C6—C7176.0 (3)C16—C11—C12—C130.1 (5)
C10—C5—C6—C72.1 (5)C2—C11—C12—C13179.9 (3)
O6—C6—C7—O70.5 (5)C11—C12—C13—C140.5 (5)
C5—C6—C7—O7178.0 (3)C12—C13—C14—C150.8 (6)
O6—C6—C7—C8179.7 (3)C13—C14—C15—C160.5 (6)
C5—C6—C7—C81.7 (5)C14—C15—C16—C110.2 (6)
O7—C7—C8—C9179.5 (3)C12—C11—C16—C150.4 (5)
C6—C7—C8—C90.3 (5)C2—C11—C16—C15179.5 (3)
C2—O1—C9—C8179.7 (3)C6A—N1A—C2A—C3A0.7 (5)
C2—O1—C9—C100.9 (4)N1A—C2A—C3A—C4A1.4 (5)
C7—C8—C9—O1179.7 (3)N1A—C2A—C3A—C7A179.9 (3)
C7—C8—C9—C100.8 (5)C2A—C3A—C4A—C5A2.3 (5)
O5—C5—C10—C9177.1 (3)C7A—C3A—C4A—C5A179.1 (3)
C6—C5—C10—C91.0 (5)C3A—C4A—C5A—C6A1.2 (5)
O5—C5—C10—C43.2 (5)C2A—N1A—C6A—C5A2.0 (5)
C6—C5—C10—C4178.7 (3)C4A—C5A—C6A—N1A1.0 (5)
O1—C9—C10—C5179.9 (3)C4A—C3A—C7A—O1A28.2 (5)
C8—C9—C10—C50.5 (5)C2A—C3A—C7A—O1A150.3 (3)
O1—C9—C10—C40.3 (5)C4A—C3A—C7A—N2A150.8 (3)
C8—C9—C10—C4179.8 (3)C2A—C3A—C7A—N2A30.7 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O5—H5···O40.841.812.563 (3)148
O6—H6···N1Ai0.841.912.694 (4)155
O7—H7···O1A0.841.942.720 (3)154
N2A—H2A2···O1Aii0.882.232.996 (4)145
C4A—H4A···O4iii0.952.323.200 (4)154
Symmetry codes: (i) x+2, y+2, z+1; (ii) x+1, y, z; (iii) x1, y+1, z.

Experimental details

Crystal data
Chemical formulaC6H6N2·C15H10O5
Mr392.36
Crystal system, space groupTriclinic, P1
Temperature (K)100
a, b, c (Å)5.248 (2), 11.422 (3), 14.952 (4)
α, β, γ (°)84.38 (3), 82.29 (3), 79.83 (3)
V3)871.7 (5)
Z2
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.48 × 0.07 × 0.04
Data collection
DiffractometerKuma KM-4-CCD κ-geometry
diffractometer with a Sapphire2 CCD area detector
Absorption correctionMulti-scan
(CrysAlis RED; Oxford Diffraction, 2009)
Tmin, Tmax0.739, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
11110, 3432, 2076
Rint0.065
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.058, 0.181, 1.08
No. of reflections3432
No. of parameters265
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.26, 0.27

Computer programs: CrysAlis CCD (Oxford Diffraction, 2009), CrysAlis RED (Oxford Diffraction, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2005).

Selected torsion angles (º) top
O1—C2—C11—C1220.0 (4)C4A—C3A—C7A—O1A28.2 (5)
C3—C2—C11—C1621.4 (5)C2A—C3A—C7A—N2A30.7 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O5—H5···O40.841.812.563 (3)147.5
O6—H6···N1Ai0.841.912.694 (4)155.3
O7—H7···O1A0.841.942.720 (3)154.0
N2A—H2A2···O1Aii0.882.232.996 (4)145.1
C4A—H4A···O4iii0.952.323.200 (4)153.6
Symmetry codes: (i) x+2, y+2, z+1; (ii) x+1, y, z; (iii) x1, y+1, z.
 

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