The cocrystal nicotinamide-succinic acid (2/1)

In the asymmetric unit of the crystal structure of nicotinamide-succinic acid (2/1), 2C₆H₆N₂O·C₄H₆O₄, there are two independent nicotinamide mol­ecules in general positions and two half succinic acid mol­ecules which lie about inversion centres. The structure contains acid-pyridine and amide-amide synthons with nicotinamide mol­ecules forming ladders of alternating R₂²(8) and R₄²(8) rings linked through succinic acid to generate a corrugated hydrogen-bonded sheet. This sheet is a common supra­molecular unit found in other 2:1 nicotinamide-dicarb­oxy­lic acid cocrystals, but the presence of two crystallographically distinct nicotinamides with anti and syn conformations, forming two distinct sheets within the same structure, is a novel packing feature in this type of material.

S1. Comment

Molecular cocrystals are becoming increasingly important within the pharmaceutical industry as they represent a new source of solid-state materials which have the potential to provide optimal physical properties while retaining the chemical properties of the individual components (Almarsson & Zaworotko, 2004; Vishweshwar et al., 2006; Blagden et al., 2008). However, successful synthesis of these multicomponent materials relies on the preferential formation of heteromeric synthons rather than the formation of strong interactions within the structures of the individual cocrystal formers. Both nicotinamide and isonicotinamide have demonstrated the propensity for cocrystal formation with a range of carboxylic acids (Aakeröy et al., 2002; Vishweshwar et al., 2003; Chakrabarty et al., 2006; Amai et al., 2006; Schmidtmann et al., 2007; Karki et al., 2009; Orola et al., 2009), showing consistent preference for the formation of a heteromeric acid–pyridine hydrogen bond (I) (Fig. 1). The formation of an amide–amide (II) or acid–amide (III) hydrogen bond (Fig. 1) is then dependent on the stoichiometry of the cocrystal; those formed with a monocarboxylic acid in 1:1 or a dicarboxylic acid in a 2:1 ratio show a preference for formation of synthon (II), whereas cocrystals with the dicarboxylic acid in a 1:1 ratio tend to form synthon (III). This is clearly illustrated in cases where both 1:1 and 2:1 cocrystal stoichiometries have been identified; for example, nicotinamide:adipic acid, nicotinamide:suberic acid (Karki et al., 2009), nicotinamide:fumaric acid (Orola et al., 2009), isonicotinamide:glutaric acid and isonicotinamide:adipic acid (Vishweshwar et al., 2003).

Here we report the crystal structure of the nicotinamide:succinic acid 2:1 cocrystal, (1). Compound (1) was prepared by slow evaporation from a 1:1 stoichiometric ratio of starting materials as previously described, although no crystal structure was reported (Karki et al., 2009).

The crystal structure of (1) displays an extended hydrogen-bond network generated by the acid–pyridine and amide–amide synthons expected in a cocrystal of this composition in a 2:1 stoichiometry, but unlike other nicotinamide:acid cocrystals, (1) contains two crystallographically distinct nicotinamide molecules with different conformations. Nicotinamide molecule A (denoted by atom labels a in Fig. 2) adopts an anti conformation with the heterocyclic N and amide N on opposite sides of the molecule [torsion angle C6A—C5A—C7A—N7A = 151.9 (2)°; Table 1] whereas nicotinamide molecule B (denoted by atom labels b in Fig. 2) adopts a syn conformation [torsion angle C6B—C5B—C7B—N7B = 26.5 (3)°; Table 1]. A search of the Cambridge Structural Database (Allen, 2002) revealed that, in other nicotinamide adducts, the nicotinamide molecule displays only one conformation in each structure (either the anti or syn), and there are more examples of structures adopting the anti rather than the syn conformation. An electron-density map was used to identify the positions of the carboxyl hydrogen atoms H8A and H8B in (1) confirming that this is a neutral cocrystal form rather than a salt (see Experimental).

Each nicotinamide molecule (A and B) is involved in four intermolecular hydrogen bonds with A and B molecules, respectively; one hard O—H···N(heterocyclic) interaction and one soft C—H···O═C hydrogen bond to a succinic acid molecule, and two hard N—H···O═C hydrogen bonds to other nicotinamide molecules of the same conformation (Table 2). More specifically, the carboxyl oxygen O8A acts as a hydrogen-bond donor, via H8A, to the heterocyclic N1A of nicotinamide A at (x, y, z) with the acid–pyridine packing motif (I) reinforced by C6A in the nicotinamide acting as a soft hydrogen-bond donor through H6A to the other carboxyl oxygen O9A at (x, y, z). Propagation of this motif through inversion within the succinic acid molecule generates the 2:1 nicotinamide:succinic acid unit in which succinic acid A is capped at both ends by molecules of nicotinamide A. These units are then linked together through a complementary amide dimer R₂²(8) motif (II) (Bernstein et al., 1995) formed by N7A via H7AA to O7A at (1-x, 2-y, 2 - z) to generate a chain running in the [201] direction. The chains are linked through a second complementary N—H···O interaction formed by N7A through H7AB donation to O7A at (-1+x, y, z) giving R₄²(8) rings and resulting in the formation of an infinite corrugated hydrogen-bonded sheet in the ac plane (Fig.3).

Nicotinamide B is involved in a similar set of intermolecular interactions with succinic acid B and other nicotinamide B molecules, generating the same synthons and motifs as nicotinamide A. The formation of a dimer with nicotinamide B at (2 - x, 1 - y, 2 - z) generates a chain linking the 2:1 nicotinamide B:succinic acid B units, which in this case runs in the [201] direction. These chains are then linked to others to give a second corrugated hydrogen-bonded sheet also in the ac plane. Hence the structure of (1) contains alternating sheets comprised purely of A molecules and then purely of B molecules in which the chains run in opposing directions (Fig. 4). There are no strong interactions between alternating sheets and all strong hydrogen-bond donors and acceptors are used in the hydrogen-bond network.

The corrugated hydrogen-bonded sheet formed by nicotinamide A in the anti conformation is a common supramolecular unit found in other 2:1 nicotinamide:dicarboxylic acid cocrystals in which the alkyl chain in the acid is longer, such as nicotinamide:adipic acid, nicotinamide:suberic acid and nicotinamide:sebacic acid (Karki et al., 2009). Similar anti conformation chains are also formed by 2:1 cocrystals with malonic and fumaric acids, but in these cases the chains are linked through a further acid–amide interaction rather than through the formation of nicotinamide ladders. There are no other reports of the syn conformation in this series of cocrystals, although it is found in the synthon (III)-based acid–amide chains formed in the 1:1 stoichiometry nicotinamide:glutaric acid and nicotinamide:pimelic acid cocrystals (Karki et al., 2009).

In conclusion, the single-crystal structure of (1) highlights the formation of a supramolecular hydrogen-bonded sheet that is also seen in other nicotinamide:dicarboxylic acid cocrystals of this stoichiometry. However, the formation of two distinct sheets with anti and syn nicotinamide conformations is a novel packing feature in this type of material. This display of both typical and atypical structural behaviour within (1) may be (i) a result of the succinic acid being at the interface of two distinct preferred packing modes dependent on the size of the acid component, or (ii) an indication that other packing modes may be exhibited through potential polymorphic behaviour.

Related literature

For related literature, see: Aakeröy et al. (2002); Allen (2002); Almarsson & Zaworotko (2004); Amai et al. (2006); Bernstein et al. (1995); Blagden et al. (2008); Chakrabarty et al. (2006); Karki et al. (2009); Orola & Veidis (2009); Schmidtmann et al. (2007); Vishweshwar et al. (2003, 2006).

S2. Experimental

All starting materials were purchased from Sigma Aldrich and used without purification. Nicotinamide (0.0138 g, 1.13 x 10^-4 mmol) and succinic acid (0.0133 g, 1.13 x 10^-4 mmol) were dissolved in warm methanol (5 ml) in a 1:1 stoichiometric ratio. The resulting solution was cooled to room temperature and, on slow evaporation of the solvent, crystals were formed. A colourless lath-shaped crystal of (1) was selected and used for single-crystal X-ray diffraction.

S3. Refinement

The presence of hydrogen atoms H8A and H8B bonded to oxygen atoms O8A and O8B, respectively [showing (1) is a cocrystal rather than a salt] was confirmed by the observation of peaks in those locations in an electron-density map, in addition to analysis of the C8A/B—O8A/B and C8A/B—O9A/B bond lengths (Table 1). All H atoms were then added at calculated positions and refined using a riding model, with C—H = 0.95 Å for aromatic H atoms, 0.99 Å for methylene H atoms, N—H = 0.88 Å and O—H = 0.84 Å and with U_iso(H) = 1.2U_eq(C) for aromatic and methylene H atoms, 1.2U_eq(N) for N—H groups and 1.5U_eq(O) for hydroxyl H atoms. In the case of the hydroxyl groups O8A—H8A and O8B—H8B the riding model used (AFIX 147) allowed the chosen C—C—O—H torsion angle to maximize the electron density at the calculated H-atom position such that the final positions for H8A and H8B are very close to the peaks initially observed in the electron-density map.

Computing details

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); data reduction: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg & Putz, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. Potential hydrogen-bond synthons found in acid–amide cocrystals.
	Fig. 2. The independent molecules of (1), showing the atom-numbering scheme and the hard intermolecular hydrogen bonds (shown as dashed lines). Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. Symmetry codes: (i) –x + 3, –y + 2, –z + 1; (ii) –x, 1–y, 1–z.
	Fig. 3. A view of the corrugated hydrogen-bonded sheet in the ac plane formed by nicotinamide A and succinic acid A. Hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonding are omitted for clarity.
	Fig. 4. A stereoview of part of the crystal structure of (1) showing the chains formed by nicotinamide A and succinic acid A running along [201] (right) and nicotinamide B and succinic acid B running along [201] (left). Hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonding are omitted for clarity.

nicotinamide–succinic acid (2/1)

Crystal data

2C6H6N2O·C4H6O4	Z = 2
Mr = 362.34	F(000) = 380
Triclinic, P1	Dx = 1.471 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.0872 (2) Å	Cell parameters from 13985 reflections
b = 11.5569 (5) Å	θ = 2.9–27.5°
c = 14.2784 (5) Å	µ = 0.12 mm^−1
α = 77.433 (2)°	T = 120 K
β = 86.726 (2)°	Lath, colourless
γ = 89.418 (2)°	0.17 × 0.03 × 0.01 mm
V = 818.01 (6) Å^3

Data collection

Bruker Nonius APEXII CCD camera on κ-goniostat diffractometer	3205 independent reflections
Radiation source: Bruker Nonius FR591 rotating anode	2455 reflections with I > 2σ(I)
10cm confocal mirrors monochromator	Rint = 0.061
Detector resolution: 4096x4096pixels / 62x62mm pixels mm^-1	θmax = 26.0°, θmin = 3.6°
ϕ & ω scans	h = −6→6
Absorption correction: multi-scan (SADABS; Sheldrick, 2007)	k = −14→14
Tmin = 0.981, Tmax = 0.999	l = −17→17
12664 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.132	H-atom parameters constrained
S = 1.11	w = 1/[σ^2(Fo^2) + (0.0321P)^2 + 1.0121P] where P = (Fo^2 + 2Fc^2)/3
3205 reflections	(Δ/σ)max < 0.001
237 parameters	Δρmax = 0.24 e Å^−3
0 restraints	Δρmin = −0.27 e Å^−3

Special details

Experimental. SADABS was used to perform the Absorption correction Parameter refinement on 11243 reflections reduced R(int) from 0.1206 to 0.0608 Ratio of minimum to maximum apparent transmission: 0.821807 The given Tmin and Tmax were generated using the SHELX SIZE command

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
C2A	0.4871 (5)	0.6850 (2)	0.69296 (18)	0.0206 (5)
H2A	0.4885	0.6440	0.6421	0.025*
C3A	0.2889 (5)	0.6599 (2)	0.76498 (18)	0.0217 (5)
H3A	0.1600	0.6012	0.7643	0.026*
C4A	0.2815 (5)	0.7214 (2)	0.83796 (18)	0.0214 (5)
H4A	0.1449	0.7071	0.8873	0.026*
C5A	0.4770 (4)	0.8044 (2)	0.83812 (17)	0.0185 (5)
C6A	0.6720 (5)	0.8224 (2)	0.76399 (17)	0.0193 (5)
H6A	0.8079	0.8780	0.7644	0.023*
C7A	0.4920 (5)	0.8766 (2)	0.91250 (17)	0.0197 (5)
N1A	0.6769 (4)	0.76476 (18)	0.69195 (15)	0.0207 (5)
N7A	0.2674 (4)	0.90012 (19)	0.95723 (15)	0.0233 (5)
H7AA	0.2687	0.9438	1.0006	0.028*
H7AB	0.1177	0.8720	0.9435	0.028*
O7A	0.7068 (3)	0.91475 (17)	0.93003 (13)	0.0264 (4)
C8A	1.2024 (4)	0.9118 (2)	0.56775 (17)	0.0167 (5)
C9A	1.4146 (5)	0.9511 (2)	0.49025 (17)	0.0195 (5)
H9AA	1.3324	0.9794	0.4282	0.023*
H9AB	1.5270	0.8823	0.4844	0.023*
O8A	1.0447 (3)	0.83088 (15)	0.54734 (12)	0.0219 (4)
H8A	0.9364	0.8072	0.5941	0.033*
O9A	1.1766 (3)	0.94944 (15)	0.64069 (12)	0.0212 (4)
C2B	0.9486 (5)	0.1801 (2)	0.69609 (18)	0.0217 (5)
H2B	0.9479	0.1351	0.6478	0.026*
C3B	1.1319 (5)	0.1529 (2)	0.76504 (18)	0.0234 (6)
H3B	1.2522	0.0896	0.7648	0.028*
C4B	1.1374 (5)	0.2194 (2)	0.83447 (17)	0.0206 (5)
H4B	1.2632	0.2031	0.8823	0.025*
C5B	0.9559 (4)	0.3105 (2)	0.83337 (17)	0.0185 (5)
C6B	0.7752 (5)	0.3301 (2)	0.76243 (17)	0.0193 (5)
H6B	0.6482	0.3910	0.7624	0.023*
C7B	0.9726 (5)	0.3884 (2)	0.90374 (17)	0.0191 (5)
N1B	0.7711 (4)	0.26738 (18)	0.69400 (14)	0.0202 (4)
N7B	0.7563 (4)	0.4459 (2)	0.92417 (15)	0.0247 (5)
H7BA	0.7607	0.4936	0.9644	0.030*
H7BB	0.6088	0.4362	0.8974	0.030*
O7B	1.1850 (3)	0.39940 (16)	0.93981 (13)	0.0248 (4)
C8B	0.2786 (4)	0.4130 (2)	0.56901 (17)	0.0179 (5)
C9B	0.0897 (5)	0.4496 (2)	0.49128 (17)	0.0195 (5)
H9BA	−0.0197	0.3805	0.4876	0.023*
H9BB	0.1901	0.4751	0.4288	0.023*
O8B	0.4439 (3)	0.32933 (15)	0.55067 (12)	0.0224 (4)
H8B	0.5417	0.3083	0.5968	0.034*
O9B	0.2844 (3)	0.45419 (15)	0.64005 (12)	0.0218 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C2A	0.0221 (12)	0.0187 (12)	0.0219 (13)	0.0023 (10)	−0.0012 (10)	−0.0069 (10)
C3A	0.0213 (12)	0.0195 (12)	0.0242 (13)	−0.0017 (10)	−0.0035 (10)	−0.0038 (10)
C4A	0.0187 (12)	0.0248 (13)	0.0195 (13)	0.0014 (10)	0.0025 (10)	−0.0031 (10)
C5A	0.0152 (11)	0.0213 (12)	0.0192 (12)	0.0023 (9)	−0.0023 (9)	−0.0047 (10)
C6A	0.0159 (11)	0.0205 (12)	0.0219 (13)	0.0003 (9)	−0.0013 (9)	−0.0056 (10)
C7A	0.0187 (12)	0.0233 (13)	0.0168 (12)	0.0001 (10)	−0.0014 (9)	−0.0037 (10)
N1A	0.0174 (10)	0.0242 (11)	0.0214 (11)	0.0009 (8)	−0.0005 (8)	−0.0072 (9)
N7A	0.0169 (10)	0.0330 (12)	0.0245 (12)	−0.0010 (9)	0.0012 (8)	−0.0166 (10)
O7A	0.0173 (9)	0.0381 (11)	0.0278 (10)	−0.0015 (8)	−0.0009 (7)	−0.0156 (8)
C8A	0.0148 (11)	0.0169 (12)	0.0189 (12)	0.0028 (9)	−0.0027 (9)	−0.0046 (10)
C9A	0.0188 (12)	0.0205 (12)	0.0203 (13)	0.0007 (10)	−0.0001 (10)	−0.0071 (10)
O8A	0.0196 (9)	0.0249 (9)	0.0220 (9)	−0.0058 (7)	0.0040 (7)	−0.0079 (8)
O9A	0.0210 (9)	0.0227 (9)	0.0211 (9)	0.0004 (7)	0.0024 (7)	−0.0080 (7)
C2B	0.0229 (13)	0.0221 (13)	0.0210 (13)	0.0006 (10)	−0.0009 (10)	−0.0069 (10)
C3B	0.0243 (13)	0.0210 (13)	0.0248 (13)	0.0034 (10)	−0.0021 (10)	−0.0045 (10)
C4B	0.0178 (12)	0.0248 (13)	0.0184 (12)	0.0000 (10)	−0.0009 (9)	−0.0028 (10)
C5B	0.0166 (11)	0.0208 (12)	0.0181 (12)	−0.0015 (9)	0.0030 (9)	−0.0050 (10)
C6B	0.0154 (11)	0.0217 (12)	0.0210 (13)	−0.0006 (9)	0.0008 (9)	−0.0056 (10)
C7B	0.0180 (12)	0.0222 (13)	0.0165 (12)	−0.0008 (10)	0.0007 (9)	−0.0036 (10)
N1B	0.0197 (10)	0.0230 (11)	0.0194 (11)	0.0013 (8)	−0.0012 (8)	−0.0075 (9)
N7B	0.0177 (10)	0.0347 (13)	0.0271 (12)	0.0027 (9)	−0.0024 (9)	−0.0183 (10)
O7B	0.0176 (9)	0.0325 (10)	0.0280 (10)	0.0011 (7)	−0.0041 (7)	−0.0142 (8)
C8B	0.0151 (11)	0.0165 (12)	0.0220 (13)	−0.0024 (9)	0.0019 (9)	−0.0045 (10)
C9B	0.0167 (12)	0.0227 (13)	0.0196 (12)	0.0013 (10)	−0.0019 (10)	−0.0055 (10)
O8B	0.0214 (9)	0.0263 (9)	0.0214 (9)	0.0073 (7)	−0.0043 (7)	−0.0090 (8)
O9B	0.0232 (9)	0.0235 (9)	0.0208 (9)	0.0026 (7)	−0.0028 (7)	−0.0090 (7)

Geometric parameters (Å, º)

C2A—N1A	1.339 (3)	C2B—N1B	1.344 (3)
C2A—C3A	1.384 (4)	C2B—C3B	1.379 (3)
C2A—H2A	0.9500	C2B—H2B	0.9500
C3A—C4A	1.382 (3)	C3B—C4B	1.382 (4)
C3A—H3A	0.9500	C3B—H3B	0.9500
C4A—C5A	1.390 (3)	C4B—C5B	1.392 (3)
C4A—H4A	0.9500	C4B—H4B	0.9500
C5A—C6A	1.391 (3)	C5B—C6B	1.387 (3)
C5A—C7A	1.491 (3)	C5B—C7B	1.494 (3)
C6A—N1A	1.341 (3)	C6B—N1B	1.338 (3)
C6A—H6A	0.9500	C6B—H6B	0.9500
C7A—O7A	1.241 (3)	C7B—O7B	1.242 (3)
C7A—N7A	1.332 (3)	C7B—N7B	1.331 (3)
N7A—H7AA	0.8800	N7B—H7BA	0.8800
N7A—H7AB	0.8800	N7B—H7BB	0.8800
C8A—O9A	1.213 (3)	C8B—O9B	1.212 (3)
C8A—O8A	1.328 (3)	C8B—O8B	1.334 (3)
C8A—C9A	1.500 (3)	C8B—C9B	1.498 (3)
C9A—C9A^i	1.516 (5)	C9B—C9B^ii	1.528 (5)
C9A—H9AA	0.9900	C9B—H9BA	0.9900
C9A—H9AB	0.9900	C9B—H9BB	0.9900
O8A—H8A	0.8400	O8B—H8B	0.8400
N1A—C2A—C3A	122.8 (2)	N1B—C2B—C3B	123.1 (2)
N1A—C2A—H2A	118.6	N1B—C2B—H2B	118.5
C3A—C2A—H2A	118.6	C3B—C2B—H2B	118.5
C4A—C3A—C2A	119.0 (2)	C2B—C3B—C4B	118.8 (2)
C4A—C3A—H3A	120.5	C2B—C3B—H3B	120.6
C2A—C3A—H3A	120.5	C4B—C3B—H3B	120.6
C3A—C4A—C5A	119.0 (2)	C3B—C4B—C5B	119.0 (2)
C3A—C4A—H4A	120.5	C3B—C4B—H4B	120.5
C5A—C4A—H4A	120.5	C5B—C4B—H4B	120.5
C4A—C5A—C6A	118.2 (2)	C6B—C5B—C4B	118.2 (2)
C4A—C5A—C7A	124.4 (2)	C6B—C5B—C7B	122.3 (2)
C6A—C5A—C7A	117.4 (2)	C4B—C5B—C7B	119.4 (2)
N1A—C6A—C5A	123.0 (2)	N1B—C6B—C5B	123.1 (2)
N1A—C6A—H6A	118.5	N1B—C6B—H6B	118.4
C5A—C6A—H6A	118.5	C5B—C6B—H6B	118.4
O7A—C7A—N7A	121.8 (2)	O7B—C7B—N7B	122.2 (2)
O7A—C7A—C5A	120.6 (2)	O7B—C7B—C5B	120.0 (2)
N7A—C7A—C5A	117.6 (2)	N7B—C7B—C5B	117.8 (2)
C2A—N1A—C6A	118.0 (2)	C6B—N1B—C2B	117.7 (2)
C7A—N7A—H7AA	120.0	C7B—N7B—H7BA	120.0
C7A—N7A—H7AB	120.0	C7B—N7B—H7BB	120.0
H7AA—N7A—H7AB	120.0	H7BA—N7B—H7BB	120.0
O9A—C8A—O8A	123.6 (2)	O9B—C8B—O8B	123.3 (2)
O9A—C8A—C9A	124.2 (2)	O9B—C8B—C9B	124.9 (2)
O8A—C8A—C9A	112.2 (2)	O8B—C8B—C9B	111.8 (2)
C8A—C9A—C9A^i	112.7 (2)	C8B—C9B—C9B^ii	112.2 (2)
C8A—C9A—H9AA	109.1	C8B—C9B—H9BA	109.2
C9A^i—C9A—H9AA	109.1	C9B^ii—C9B—H9BA	109.2
C8A—C9A—H9AB	109.1	C8B—C9B—H9BB	109.2
C9A^i—C9A—H9AB	109.1	C9B^ii—C9B—H9BB	109.2
H9AA—C9A—H9AB	107.8	H9BA—C9B—H9BB	107.9
C8A—O8A—H8A	109.5	C8B—O8B—H8B	109.5
N1A—C2A—C3A—C4A	1.7 (4)	N1B—C2B—C3B—C4B	−1.2 (4)
C2A—C3A—C4A—C5A	−1.6 (3)	C2B—C3B—C4B—C5B	0.8 (4)
C3A—C4A—C5A—C6A	0.3 (3)	C3B—C4B—C5B—C6B	0.4 (3)
C3A—C4A—C5A—C7A	−180.0 (2)	C3B—C4B—C5B—C7B	−175.7 (2)
C4A—C5A—C6A—N1A	1.2 (3)	C4B—C5B—C6B—N1B	−1.5 (4)
C7A—C5A—C6A—N1A	−178.6 (2)	C7B—C5B—C6B—N1B	174.4 (2)
C4A—C5A—C7A—O7A	153.6 (2)	C6B—C5B—C7B—O7B	−152.2 (2)
C6A—C5A—C7A—O7A	−26.7 (3)	C4B—C5B—C7B—O7B	23.7 (3)
C4A—C5A—C7A—N7A	−27.8 (3)	C6B—C5B—C7B—N7B	26.5 (3)
C6A—C5A—C7A—N7A	151.9 (2)	C4B—C5B—C7B—N7B	−157.6 (2)
C3A—C2A—N1A—C6A	−0.3 (3)	C5B—C6B—N1B—C2B	1.3 (4)
C5A—C6A—N1A—C2A	−1.2 (3)	C3B—C2B—N1B—C6B	0.1 (4)
O9A—C8A—C9A—C9A^i	−3.5 (4)	O9B—C8B—C9B—C9B^ii	2.9 (4)
O8A—C8A—C9A—C9A^i	176.4 (2)	O8B—C8B—C9B—C9B^ii	−176.6 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N7A—H7AA···O7A^iii	0.88	2.10	2.952 (3)	164
N7A—H7AB···O7A^iv	0.88	2.15	2.899 (3)	142
O8A—H8A···N1A	0.84	1.85	2.693 (3)	175
N7B—H7BA···O7B^v	0.88	2.06	2.941 (3)	174
N7B—H7BB···O7B^iv	0.88	2.23	2.948 (3)	139
O8B—H8B···N1B	0.84	1.84	2.683 (2)	177

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