Dimorphic forms of 3,6-dinitro­durene in a single space group

3,6-Dinitro­durene (1,2,4,5-tetra­methyl-3,6-dinitro­benzene), C₁₀H₁₂N₂O₄, has been crystallized in two polymorphic forms which may be distinguished by their colours in the solid state. Polymorph I gives clear colourless prismatic crystals, while polymorph II crystallizes in the dark and under an inert atmosphere as irregular purple blocks. Both forms belong to the space group C2/c, with both asymmetric units containing two half-mol­ecules. One mol­ecule is located on an inversion centre and the other lies on a twofold axis. The polymorphism arises from different orientations of the twofold axis: in form I, this axis passes through the mid-points of two C-C bonds of the benzene ring and, as a consequence, all atoms in the asymmetric unit are in general positions. In form II, the N atoms of the nitro groups and the C_ipso atoms are located on the binary axis. Comparing phases I and II, slightly different conformations are observed for the nitro substituents, while the stacking structures are very similar.

S1. Comment

Durene (1,2,4,5-tetramethylbenzene), (1), is a highly symmetric molecule belonging to point group D_2h (Prince et al., 1973). Numerous homo-3,6-disubstituted durene derivatives have been prepared, one of the first being 3,6-dinitrodurene, obtained by direct nitration of durene (Smith & Dobrovolny, 1926). A preliminary X-ray characterization of this molecule appeared 50 years ago, which reports cell parameters and space group (Trotter, 1959). However, for unclear reasons, that characterization was never completed. In the general class of D_2h-durene derivatives, polymorphism is unusual and has been clearly described to date only for hexamethylbenzene (Le Maguères et al., 2001). We have now detected that at least two C2/c polymorphs are stabilized for the title molecule, and report here their structures.

The title compound was initially synthesized as a starting material for the preparation of polyimide membranes intended for gas separation. During the purification of this material, one batch was recrystallized from methanol, affording, as invariably described in the literature, well shaped colourless crystals (polymorph I hereafter). However, another batch, serendipitously left in the dark and under an inert atmosphere, gave irregular purple crystals (polymorph II hereafter). Providing that crystallizations are carried out as slowly as possible, pure phases may be obtained and concomitant polymorphs were not observed.

All D_2h-durene derivatives previously characterized by X-ray analysis crystallize with the molecule(s) placed on an inversion centre (e.g. tetramethylhydroquinone: Pennington et al., 1986; dicyanodurene: Britton & van Rij, 1991). By contrast, the title compound is a Z' = 1 structure with two half-molecules per asymmetric unit in both phases. One molecule is located on an inversion centre and the other molecule on a twofold axis. The dimorphism results from the position of the C₂ molecule in the cell. Indeed, two special orientations are consistent for this molecule in the space group C2/c, assuming an ideal D_2h molecular symmetry. The crystallographic twofold axis may correspond to the molecular C₂ axis containing the N atoms of the nitro groups, or to the other C₂ axis in the same plane and normal to the first. The latter arrangement is found in polymorph I (Fig. 1), while the former is observed in polymorph II (Fig. 2), a situation reminiscent of that reported for another dimorphic D_2h molecule, namely 2,3,5,6-tetraphenylpyrazine (Bartnik et al., 1999). As a consequence, all atoms in polymorph I are located in general positions, while in polymorph II, atoms C6, C9, N2 and N3 are in special positions. The unit cells have approximately identical parameters and volumes, with a different orientation for the binary axis. The polymorphism in a single space group seems to be a poorly documented matter, probably because it is an uncommon phenomenon. It should, however, arise for good reasons rather than on a random basis, and thus deserves efforts to be understood. For example, it was recently claimed that a specific crystal nucleation mechanism may be related to the existence of nonconcomitant polymorphs (Burley & Prior, 2006).

Polymorphism does not affect significantly the molecular structure of the title molecule. As expected, the nitro groups are almost perpendicular to the benzene rings in order to avoid steric hindrance with the methyl substituents. Such a resonance inhibition is common in polysubstituted nitrobenzene derivatives (e.g. 1,2,4,5-tetrachloro-3,6-dinitrobenzene: Wigand et al., 1987) and is not surprising, as it has been shown that the energy required for tilting a nitro group out of a benzene plane is rather low (Dashevskii et al., 1966). In polymorph I, dihedral angle between the nitro and benzene mean planes is 85.60 (10)° for the centrosymmetric molecule and 79.76 (8)° in the other molecule. In polymorph II, the centrosymmetric molecule has nitro groups titled as in polymorph I, δ = 86.11 (13)°, while the C₂ molecule has two nitro-tilting angles, viz. 75.75 (15) and 85.82 (13)°.

Both crystal structures are built up of mixed stacks alternating centrosymmetric and C₂ molecules. In polymorph I, stacks run along the [001] axis (Fig. 1, inset), giving a separation between molecules close to c/4, as already devised by Trotter (1959), who noted that reflection (004) has a strong intensity. Actually, centroids of neighbouring benzene rings in polymorph I are separated by 4.238 (1)Å, with a dihedral angle of 4.01 (5)°. In polymorph II, although the stack orientation deviates from cell axis c (Fig. 2, inset), the geometric parameters are very close to those observed in form I: molecules are separated by 4.285 (1)Å and tilted by 3.99 (5)°. In both forms, nitro groups within a stack adopt a staggered arrangement, minimizing intermolecular hindrance.

Finally, an obvious concern is to explain why, despite so similar molecular and crystal structures, polymorphs I and II present different colours in the solid state. X-ray structures of isomers of the title compound have been reported. m-Dinitrodurene is a colourless solid, with molecules packed at a 4.342Å distance and parallel in a stack (Ori et al., 1989). o-Dinitrodurene is reported as a yellow solid, and molecules are separated by 4.119 or 4.215Å (Sgarabotto et al., 1989). In that case, the yellow colour is likely a consequence of the shift of the π → π* transition expected for a benzene ring substituted by two σ-electron withdrawing chromophores. The situation is completely different in form II of p-dinitrodurene, which presents a well defined absorption at λ = 598 nm, even when highly diluted in tetrahydrofuran (Fig. 3). In the visible range, polymorph I does not absorb at all in solution. On the other hand, π → π* and n → π* transitions of nitro groups are known to be characterized by low extinction coefficients. We thus assume than some kind of agostic (attractive) interaction allows the molecules to arrange as dimers or oligomers in solution in the case of polymorph II, and that such an arrangement survives the nucleation step. The resulting π–π interactions would then account for the visible absorption. Slow crystallization in noncontrolled conditions can produce the colourless polymorph I, indicating that the agostic interactions are low in energy.

Related literature

For related literature, see: Bartnik et al. (1999); Britton & van Rij (1991); Burley & Prior (2006); Dashevskii et al. (1966); Le Maguères, Lindeman & Kochi (2001); Ori et al. (1989); Pennington et al. (1986); Prince et al. (1973); Sgarabotto et al. (1989); Smith & Dobrovolny (1926); Trotter (1959); Wigand et al. (1987).

S2. Experimental

Durene (98%, Aldrich), nitric acid (66.5%), sulfuric acid (98.5%), hexane and methanol (99.96%, Baker) were used for the nitration. In a two-necked vessel equipped with a refrigerant, the nitrating mixture HNO₃:H₂SO₄ was prepared in a 4:6 molar ratio. Durene was dissolved in hexane and then added slowly to the reaction vessel under stirring. During the reaction, it is important to check that temperature does not exceed 313 K. After duerene addition was completed, the mixture was further stirred for 2 h at 313 K. The resulting solid was then washed with large amounts of water and recrystallized, first from tetrahydrofuran and then from methanol. Colourless crystals (polymorph I) were obtained on crystallization carried out without special precautions, while using a dark vessel and under an inert atmosphere purple crystals were obtained (polymorph II). Slow crystallization is essential to obtain pure form I or form II crystals. The crystals are air-stable for several months.

S3. Refinement

Although polymorph I affords large and well shaped crystals, they are poorly diffracting and data were collected at low temperature (work done in Toulouse). In order to rule out a possible low-temperature phase transition, cell parameters were also measured at 298 K and did not show any symmetry modification. The data for polymorph II were collected at room temperature (work done in Monterrey). In both structures, data resolution allowed accurate positions for all H atoms to be determined, which were then freely refined. In the case of polymorph II, H atoms are disordered over two positions, due to a free rotation of the methyl groups about the C—C σ bonds. Each part of the disordered groups was restrained to approximate an ideal tetrahedral geometry by restraining C—H and H···H distances to a target geometry identical for all methyl groups. C—H bond lengths converged to 1.003 (19)–1.046 (18)Å. Occupancies were refined to common values for all methyl groups, constraining the sum of occupancies in each group to 1. Occupancies converged to 0.621 (12) and 0.379 (12). The same behaviour is probably also present in polymorph I, but limited at 180 (2) K, and methyl groups were eventually refined with nondisordered H atoms. In polymorph I, C—H bond lengths are in the range 0.89 (3)–1.02 (3)Å. Isotropic displacement parameters for H atoms were refined to a single value in each structure, and converged to 0.071 (2) and 0.071 (3)Ų for polymorphs I and II, respectively.

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2007) for polymorph_I; XSCANS (Siemens, 1996) for polymorph_II. Cell refinement: CrysAlis RED (Oxford Diffraction, 2007) for polymorph_I; XSCANS (Siemens, 1996) for polymorph_II. Data reduction: CrysAlis RED (Oxford Diffraction, 2007) for polymorph_I; XSCANS (Siemens, 1996) for polymorph_II. For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 (Sheldrick, 2008) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of polymorph I. The upper molecule is located on an inversion centre and nonlabelled atoms are generated through the symmetry code (1-x, 1-y, 1-z); the lower molecule is located on a binary axis and the symmetry code for the nonlabelled atoms is (1-x, y, 3/2-z). Displacement ellipsoids are shown at the 20% probability level. The inset shows part of the crystal structure, including one stack of molecules.
	Fig. 2. The molecular structure of polymorph II. The upper molecule is located on an inversion centre and nonlabelled atoms are generated through the symmetry code (1/2-x, 1/2-y, 1-z); the lower molecule is located on a binary axis and the symmetry code for the nonlabelled atoms is (1-x, y, 3/2-z). Displacement ellipsoids are shown at the 20% probability level. The inset shows part of the crystal structure, including one stack of molecules.
	Fig. 3. Electronic spectra of polymorphs I and II of the title compound. Samples were dissolved in tetrahydrofuran and the concentrations were 440 and 630 p.p.m. for I and II, respectively. The figure displays the visible region of the spectra, while the UV region (not shown) features the expected π → π* transitions of the aromatic systems.

(polymorph_I) 1,2,4,5-tetramethyl-3,6-dinitrobenzene

Crystal data

C10H12N2O4	F(000) = 944
Mr = 224.22	Dx = 1.405 Mg m^−3
Monoclinic, C2/c	Melting point: 485.9 K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 15.1088 (11) Å	Cell parameters from 3138 reflections
b = 8.9454 (5) Å	θ = 2.6–32.1°
c = 15.9300 (13) Å	µ = 0.11 mm^−1
β = 100.131 (8)°	T = 180 K
V = 2119.4 (3) Å^3	Flattened box, colourless
Z = 8	0.46 × 0.34 × 0.13 mm

Data collection

Oxford-Diffraction Xcalibur diffractometer	1551 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.062
Graphite monochromator	θmax = 26.4°, θmin = 2.7°
Detector resolution: 8.2632 pixels mm^-1	h = −13→18
ω and ϕ scans	k = −11→11
7776 measured reflections	l = −19→19
2155 independent 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)] = 0.047	Hydrogen site location: difference Fourier map
wR(F^2) = 0.130	All H-atom parameters refined
S = 1.08	w = 1/[σ^2(Fo^2) + (0.065P)^2 + 0.6452P] where P = (Fo^2 + 2Fc^2)/3
2155 reflections	(Δ/σ)max < 0.001
182 parameters	Δρmax = 0.21 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3
0 constraints

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

	x	y	z	Uiso*/Ueq
C1	0.53044 (12)	0.63721 (18)	0.49463 (11)	0.0266 (4)
C2	0.44184 (11)	0.62274 (19)	0.50461 (11)	0.0270 (4)
C3	0.40944 (11)	0.47793 (19)	0.51046 (11)	0.0267 (4)
C4	0.38184 (14)	0.7561 (2)	0.50727 (15)	0.0369 (5)
H4A	0.3328 (18)	0.744 (3)	0.4592 (16)	0.071 (2)*
H4B	0.4097 (17)	0.852 (3)	0.5056 (17)	0.071 (2)*
H4C	0.3560 (17)	0.751 (3)	0.5578 (17)	0.071 (2)*
C5	0.31418 (13)	0.4508 (3)	0.52042 (15)	0.0385 (5)
H5A	0.2764 (17)	0.482 (3)	0.4713 (16)	0.071 (2)*
H5B	0.3033 (17)	0.347 (3)	0.5343 (16)	0.071 (2)*
H5C	0.2984 (16)	0.506 (3)	0.5684 (16)	0.071 (2)*
N1	0.56375 (10)	0.79138 (17)	0.48764 (10)	0.0328 (4)
O1	0.56080 (13)	0.84296 (16)	0.41743 (10)	0.0634 (5)
O2	0.59214 (13)	0.85824 (16)	0.55211 (10)	0.0630 (5)
C6	0.41353 (11)	0.66207 (19)	0.75391 (11)	0.0256 (4)
C7	0.45425 (11)	0.80055 (19)	0.75192 (11)	0.0263 (4)
C8	0.45422 (11)	0.52386 (19)	0.75245 (11)	0.0275 (4)
C9	0.40340 (14)	0.9442 (2)	0.75401 (14)	0.0374 (5)
H9A	0.3470 (18)	0.925 (3)	0.7725 (16)	0.071 (2)*
H9B	0.4396 (17)	1.017 (3)	0.7963 (16)	0.071 (2)*
H9C	0.3921 (17)	0.980 (3)	0.7000 (17)	0.071 (2)*
C10	0.40414 (15)	0.3801 (2)	0.75598 (16)	0.0406 (5)
H10A	0.4121 (17)	0.318 (3)	0.7097 (17)	0.071 (2)*
H10B	0.4254 (17)	0.331 (3)	0.8065 (18)	0.071 (2)*
H10C	0.3452 (19)	0.396 (3)	0.7512 (17)	0.071 (2)*
N2	0.31621 (10)	0.66225 (17)	0.75594 (10)	0.0334 (4)
O3	0.29181 (9)	0.6407 (2)	0.82301 (10)	0.0572 (5)
O4	0.26546 (9)	0.68319 (19)	0.68913 (9)	0.0508 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0308 (9)	0.0199 (9)	0.0285 (9)	−0.0017 (7)	0.0031 (7)	0.0009 (6)
C2	0.0301 (9)	0.0232 (9)	0.0268 (9)	0.0036 (7)	0.0031 (7)	−0.0003 (6)
C3	0.0262 (9)	0.0262 (9)	0.0273 (9)	0.0014 (7)	0.0033 (7)	−0.0020 (7)
C4	0.0360 (11)	0.0256 (10)	0.0500 (13)	0.0092 (8)	0.0105 (9)	0.0017 (9)
C5	0.0314 (10)	0.0366 (11)	0.0488 (13)	−0.0007 (9)	0.0105 (9)	−0.0049 (9)
N1	0.0371 (9)	0.0240 (8)	0.0380 (9)	−0.0010 (7)	0.0088 (7)	−0.0007 (7)
O1	0.1080 (14)	0.0399 (9)	0.0445 (10)	−0.0202 (8)	0.0193 (9)	0.0085 (7)
O2	0.1053 (14)	0.0303 (8)	0.0494 (10)	−0.0217 (8)	0.0020 (9)	−0.0072 (7)
C6	0.0211 (8)	0.0279 (9)	0.0278 (9)	−0.0010 (7)	0.0040 (7)	0.0009 (7)
C7	0.0281 (8)	0.0235 (9)	0.0272 (9)	0.0017 (7)	0.0050 (7)	0.0008 (7)
C8	0.0301 (9)	0.0229 (9)	0.0281 (9)	−0.0043 (7)	0.0015 (7)	0.0004 (7)
C9	0.0407 (11)	0.0265 (10)	0.0460 (12)	0.0083 (8)	0.0105 (10)	0.0019 (8)
C10	0.0423 (12)	0.0259 (10)	0.0517 (14)	−0.0094 (9)	0.0031 (10)	0.0024 (9)
N2	0.0286 (8)	0.0341 (9)	0.0378 (9)	−0.0019 (7)	0.0064 (7)	−0.0017 (7)
O3	0.0364 (8)	0.0937 (14)	0.0448 (9)	−0.0099 (8)	0.0165 (7)	0.0072 (8)
O4	0.0291 (7)	0.0771 (11)	0.0433 (9)	0.0080 (7)	−0.0015 (6)	0.0000 (7)

Geometric parameters (Å, º)

C1—C2	1.382 (3)	C6—C8	1.383 (2)
C1—C3^i	1.385 (2)	C6—C7	1.386 (2)
C1—N1	1.479 (2)	C6—N2	1.476 (2)
C2—C3	1.394 (2)	C7—C7^ii	1.394 (3)
C2—C4	1.504 (2)	C7—C9	1.501 (2)
C3—C1^i	1.385 (2)	C8—C8^ii	1.399 (3)
C3—C5	1.495 (3)	C8—C10	1.498 (3)
C4—H4A	0.97 (3)	C9—H9A	0.96 (3)
C4—H4B	0.96 (3)	C9—H9B	1.02 (3)
C4—H4C	0.95 (3)	C9—H9C	0.91 (3)
C5—H5A	0.93 (2)	C10—H10A	0.95 (3)
C5—H5B	0.97 (3)	C10—H10B	0.92 (3)
C5—H5C	0.98 (3)	C10—H10C	0.89 (3)
N1—O2	1.201 (2)	N2—O3	1.205 (2)
N1—O1	1.203 (2)	N2—O4	1.212 (2)
C2—C1—C3^i	126.56 (16)	C8—C6—C7	126.74 (16)
C2—C1—N1	116.45 (14)	C8—C6—N2	116.67 (14)
C3^i—C1—N1	116.98 (15)	C7—C6—N2	116.58 (14)
C1—C2—C3	116.98 (15)	C6—C7—C7^ii	116.65 (10)
C1—C2—C4	122.00 (16)	C6—C7—C9	122.26 (16)
C3—C2—C4	121.01 (16)	C7^ii—C7—C9	121.09 (11)
C1^i—C3—C2	116.46 (16)	C6—C8—C8^ii	116.60 (10)
C1^i—C3—C5	122.59 (16)	C6—C8—C10	122.53 (17)
C2—C3—C5	120.94 (16)	C8^ii—C8—C10	120.86 (11)
C2—C4—H4A	105.8 (16)	C7—C9—H9A	109.9 (16)
C2—C4—H4B	116.2 (15)	C7—C9—H9B	110.0 (14)
H4A—C4—H4B	111 (2)	H9A—C9—H9B	108 (2)
C2—C4—H4C	109.0 (16)	C7—C9—H9C	107.2 (17)
H4A—C4—H4C	107 (2)	H9A—C9—H9C	109 (2)
H4B—C4—H4C	108 (2)	H9B—C9—H9C	113 (2)
C3—C5—H5A	108.8 (16)	C8—C10—H10A	110.1 (16)
C3—C5—H5B	112.5 (16)	C8—C10—H10B	109.9 (16)
H5A—C5—H5B	112 (2)	H10A—C10—H10B	109 (2)
C3—C5—H5C	111.9 (15)	C8—C10—H10C	111.3 (18)
H5A—C5—H5C	108 (2)	H10A—C10—H10C	107 (2)
H5B—C5—H5C	103 (2)	H10B—C10—H10C	110 (2)
O2—N1—O1	123.59 (16)	O3—N2—O4	123.93 (16)
O2—N1—C1	118.38 (16)	O3—N2—C6	118.70 (15)
O1—N1—C1	118.04 (15)	O4—N2—C6	117.36 (15)
C3^i—C1—C2—C3	0.2 (3)	C8—C6—C7—C7^ii	0.0 (3)
N1—C1—C2—C3	179.42 (14)	N2—C6—C7—C7^ii	−178.62 (18)
C3^i—C1—C2—C4	−178.51 (17)	C8—C6—C7—C9	−179.86 (17)
N1—C1—C2—C4	0.7 (3)	N2—C6—C7—C9	1.6 (3)
C1—C2—C3—C1^i	−0.2 (3)	C7—C6—C8—C8^ii	−0.7 (3)
C4—C2—C3—C1^i	178.55 (16)	N2—C6—C8—C8^ii	177.87 (18)
C1—C2—C3—C5	−179.35 (16)	C7—C6—C8—C10	179.20 (18)
C4—C2—C3—C5	−0.6 (3)	N2—C6—C8—C10	−2.2 (3)
C2—C1—N1—O2	85.9 (2)	C8—C6—N2—O3	79.9 (2)
C3^i—C1—N1—O2	−94.8 (2)	C7—C6—N2—O3	−101.37 (19)
C2—C1—N1—O1	−94.0 (2)	C8—C6—N2—O4	−99.54 (19)
C3^i—C1—N1—O1	85.3 (2)	C7—C6—N2—O4	79.2 (2)

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

(polymorph_II) 1,2,4,5-tetramethyl-3,6-dinitrobenzene

Crystal data

C10H12N2O4	F(000) = 944
Mr = 224.22	Dx = 1.372 Mg m^−3
Monoclinic, C2/c	Melting point: 486.3 K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 8.9592 (19) Å	Cell parameters from 65 reflections
b = 15.313 (3) Å	θ = 5.1–12.1°
c = 16.136 (4) Å	µ = 0.11 mm^−1
β = 101.300 (13)°	T = 298 K
V = 2170.8 (9) Å^3	Irregular, light violet
Z = 8	0.40 × 0.30 × 0.16 mm

Data collection

Bruker P4 diffractometer	Rint = 0.036
Radiation source: fine-focus sealed tube, FN4	θmax = 27.5°, θmin = 2.6°
Graphite monochromator	h = −11→8
2θ/ω scans	k = −19→19
6214 measured reflections	l = −20→20
2492 independent reflections	3 standard reflections every 97 reflections
1423 reflections with I > 2σ(I)	intensity decay: 1.5%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.051	All H-atom parameters refined
wR(F^2) = 0.152	w = 1/[σ^2(Fo^2) + (0.0599P)^2 + 0.8126P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max < 0.001
2492 reflections	Δρmax = 0.19 e Å^−3
223 parameters	Δρmin = −0.14 e Å^−3
48 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 constraints	Extinction coefficient: 0.0079 (14)
Primary atom site location: structure-invariant direct methods

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
C1	0.1149 (2)	0.21810 (13)	0.50352 (12)	0.0502 (5)
C2	0.2316 (2)	0.15849 (12)	0.50620 (12)	0.0520 (5)
C3	0.3747 (2)	0.19240 (13)	0.50241 (12)	0.0515 (5)
C4	0.2064 (3)	0.06200 (14)	0.51183 (17)	0.0718 (7)
H4A	0.098 (2)	0.046 (2)	0.513 (3)	0.071 (3)*	0.621 (12)
H4B	0.277 (4)	0.036 (2)	0.5638 (17)	0.071 (3)*	0.621 (12)
H4C	0.239 (4)	0.034 (2)	0.4598 (17)	0.071 (3)*	0.621 (12)
H4D	0.169 (7)	0.046 (3)	0.566 (2)	0.071 (3)*	0.379 (12)
H4E	0.298 (4)	0.023 (3)	0.508 (4)	0.071 (3)*	0.379 (12)
H4F	0.121 (5)	0.045 (3)	0.462 (3)	0.071 (3)*	0.379 (12)
C5	0.5097 (3)	0.13376 (16)	0.50392 (17)	0.0695 (6)
H5A	0.606 (3)	0.166 (2)	0.496 (3)	0.071 (3)*	0.621 (12)
H5B	0.484 (4)	0.088 (2)	0.4577 (18)	0.071 (3)*	0.621 (12)
H5C	0.535 (4)	0.100 (2)	0.5610 (15)	0.071 (3)*	0.621 (12)
H5D	0.546 (7)	0.136 (4)	0.448 (2)	0.071 (3)*	0.379 (12)
H5E	0.484 (6)	0.0726 (19)	0.518 (4)	0.071 (3)*	0.379 (12)
H5F	0.591 (5)	0.160 (3)	0.550 (3)	0.071 (3)*	0.379 (12)
N1	−0.0361 (2)	0.18273 (13)	0.50863 (13)	0.0645 (5)
O1	−0.1241 (2)	0.16849 (17)	0.44499 (13)	0.1100 (8)
O2	−0.0633 (2)	0.16989 (17)	0.57750 (12)	0.1106 (8)
C6	0.5000	0.28452 (17)	0.7500	0.0529 (7)
C7	0.3621 (2)	0.24401 (13)	0.74974 (12)	0.0537 (5)
C8	0.3626 (2)	0.15333 (13)	0.75039 (11)	0.0517 (5)
C9	0.5000	0.11309 (17)	0.7500	0.0494 (6)
C10	0.2181 (3)	0.29374 (18)	0.75006 (18)	0.0780 (7)
H10A	0.238 (4)	0.3580 (13)	0.748 (2)	0.071 (3)*	0.621 (12)
H10B	0.176 (4)	0.279 (2)	0.8035 (15)	0.071 (3)*	0.621 (12)
H10C	0.140 (3)	0.274 (2)	0.6987 (16)	0.071 (3)*	0.621 (12)
H10D	0.181 (6)	0.321 (4)	0.6930 (17)	0.071 (3)*	0.379 (12)
H10E	0.236 (6)	0.340 (3)	0.796 (3)	0.071 (3)*	0.379 (12)
H10F	0.139 (5)	0.250 (3)	0.763 (4)	0.071 (3)*	0.379 (12)
C11	0.2205 (3)	0.10191 (18)	0.75218 (17)	0.0748 (7)
H11A	0.133 (3)	0.128 (2)	0.7075 (19)	0.071 (3)*	0.621 (12)
H11B	0.190 (4)	0.101 (2)	0.8091 (12)	0.071 (3)*	0.621 (12)
H11C	0.229 (4)	0.0368 (14)	0.734 (2)	0.071 (3)*	0.621 (12)
H11D	0.139 (5)	0.136 (3)	0.775 (4)	0.071 (3)*	0.379 (12)
H11E	0.243 (6)	0.044 (2)	0.785 (3)	0.071 (3)*	0.379 (12)
H11F	0.178 (6)	0.087 (4)	0.6900 (14)	0.071 (3)*	0.379 (12)
N2	0.5000	0.38077 (18)	0.7500	0.0743 (8)
O3	0.4486 (3)	0.41777 (12)	0.68592 (13)	0.1150 (8)
N3	0.5000	0.01670 (16)	0.7500	0.0619 (7)
O4	0.4850 (2)	−0.02067 (11)	0.68347 (11)	0.0963 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0376 (10)	0.0605 (12)	0.0534 (11)	−0.0023 (9)	0.0106 (8)	−0.0003 (9)
C2	0.0453 (11)	0.0509 (11)	0.0595 (11)	0.0002 (9)	0.0092 (8)	−0.0010 (9)
C3	0.0454 (11)	0.0571 (12)	0.0527 (11)	0.0069 (9)	0.0111 (8)	−0.0018 (9)
C4	0.0663 (15)	0.0525 (12)	0.0938 (18)	−0.0005 (11)	0.0087 (13)	0.0015 (11)
C5	0.0549 (14)	0.0700 (15)	0.0862 (16)	0.0155 (11)	0.0202 (12)	−0.0006 (12)
N1	0.0431 (10)	0.0774 (12)	0.0743 (12)	−0.0036 (9)	0.0149 (9)	0.0048 (10)
O1	0.0545 (10)	0.180 (2)	0.0905 (13)	−0.0356 (12)	0.0034 (9)	−0.0063 (13)
O2	0.0758 (13)	0.175 (2)	0.0882 (14)	−0.0304 (13)	0.0329 (10)	0.0234 (13)
C6	0.0587 (17)	0.0437 (15)	0.0561 (16)	0.000	0.0104 (13)	0.000
C7	0.0476 (11)	0.0566 (12)	0.0572 (11)	0.0063 (9)	0.0112 (9)	−0.0043 (9)
C8	0.0435 (11)	0.0585 (12)	0.0547 (11)	−0.0032 (9)	0.0136 (8)	−0.0028 (9)
C9	0.0509 (16)	0.0456 (14)	0.0526 (15)	0.000	0.0127 (12)	0.000
C10	0.0605 (15)	0.0827 (17)	0.0905 (18)	0.0194 (13)	0.0140 (13)	−0.0061 (14)
C11	0.0550 (14)	0.0858 (17)	0.0877 (17)	−0.0184 (12)	0.0239 (12)	−0.0065 (14)
N2	0.092 (2)	0.0534 (15)	0.0762 (19)	0.000	0.0141 (16)	0.000
O3	0.181 (2)	0.0633 (11)	0.0924 (14)	0.0316 (12)	0.0069 (13)	0.0147 (10)
N3	0.0684 (16)	0.0527 (14)	0.0643 (15)	0.000	0.0123 (12)	0.000
O4	0.1449 (18)	0.0611 (10)	0.0804 (12)	0.0085 (11)	0.0162 (11)	−0.0170 (9)

Geometric parameters (Å, º)

C1—C3^i	1.378 (3)	C6—N2	1.474 (4)
C1—C2	1.382 (3)	C7—C8	1.389 (3)
C1—N1	1.475 (3)	C7—C10	1.499 (3)
C2—C3	1.396 (3)	C8—C9	1.378 (2)
C2—C4	1.500 (3)	C8—C11	1.502 (3)
C3—C1^i	1.378 (3)	C9—C8^ii	1.378 (2)
C3—C5	1.502 (3)	C9—N3	1.476 (4)
C4—H4A	1.005 (17)	C10—H10A	1.003 (18)
C4—H4B	1.024 (17)	C10—H10B	1.030 (17)
C4—H4C	1.034 (17)	C10—H10C	1.020 (17)
C4—H4D	1.02 (2)	C10—H10D	1.003 (19)
C4—H4E	1.03 (2)	C10—H10E	1.02 (2)
C4—H4F	1.04 (2)	C10—H10F	1.023 (19)
C5—H5A	1.024 (18)	C11—H11A	1.035 (18)
C5—H5B	1.011 (17)	C11—H11B	1.008 (18)
C5—H5C	1.038 (17)	C11—H11C	1.046 (18)
C5—H5D	1.014 (19)	C11—H11D	1.018 (19)
C5—H5E	1.004 (19)	C11—H11E	1.03 (2)
C5—H5F	1.02 (2)	C11—H11F	1.03 (2)
N1—O1	1.186 (2)	N2—O3^ii	1.190 (2)
N1—O2	1.200 (2)	N2—O3	1.190 (2)
C6—C7	1.382 (2)	N3—O4	1.2006 (19)
C6—C7^ii	1.382 (2)	N3—O4^ii	1.2006 (19)
C3^i—C1—C2	126.77 (18)	C6—C7—C8	116.60 (18)
C3^i—C1—N1	116.35 (17)	C6—C7—C10	122.8 (2)
C2—C1—N1	116.88 (18)	C8—C7—C10	120.6 (2)
C1—C2—C3	116.64 (17)	C9—C8—C7	116.63 (18)
C1—C2—C4	122.08 (19)	C9—C8—C11	121.8 (2)
C3—C2—C4	121.27 (18)	C7—C8—C11	121.56 (19)
C1^i—C3—C2	116.59 (17)	C8^ii—C9—C8	126.9 (2)
C1^i—C3—C5	122.05 (19)	C8^ii—C9—N3	116.56 (12)
C2—C3—C5	121.35 (19)	C8—C9—N3	116.56 (12)
C2—C4—H4A	114 (2)	C7—C10—H10A	110 (2)
C2—C4—H4B	110.6 (19)	C7—C10—H10B	110.3 (19)
H4A—C4—H4B	110 (2)	H10A—C10—H10B	110 (2)
C2—C4—H4C	106.9 (19)	C7—C10—H10C	107.4 (19)
H4A—C4—H4C	109 (2)	H10A—C10—H10C	112 (2)
H4B—C4—H4C	106.2 (19)	H10B—C10—H10C	108.2 (19)
C2—C4—H4D	112 (3)	C7—C10—H10D	109 (3)
H4A—C4—H4D	57 (3)	H10A—C10—H10D	66 (3)
H4B—C4—H4D	58 (3)	H10B—C10—H10D	139 (4)
H4C—C4—H4D	141 (4)	H10C—C10—H10D	48 (3)
C2—C4—H4E	116 (3)	C7—C10—H10E	110 (3)
H4A—C4—H4E	130 (4)	H10A—C10—H10E	48 (3)
H4B—C4—H4E	57 (3)	H10B—C10—H10E	65 (3)
H4C—C4—H4E	50 (3)	H10C—C10—H10E	142 (4)
H4D—C4—H4E	108 (2)	H10D—C10—H10E	111 (3)
C2—C4—H4F	108 (3)	C7—C10—H10F	107 (3)
H4A—C4—H4F	51 (3)	H10A—C10—H10F	142 (4)
H4B—C4—H4F	142 (3)	H10B—C10—H10F	46 (3)
H4C—C4—H4F	63 (3)	H10C—C10—H10F	65 (3)
H4D—C4—H4F	107 (2)	H10D—C10—H10F	110 (2)
H4E—C4—H4F	106 (2)	H10E—C10—H10F	109 (2)
C3—C5—H5A	113.7 (19)	C8—C11—H11A	107.9 (19)
C3—C5—H5B	109.4 (19)	C8—C11—H11B	114.0 (19)
H5A—C5—H5B	108 (2)	H11A—C11—H11B	110 (2)
C3—C5—H5C	110.0 (19)	C8—C11—H11C	112.8 (19)
H5A—C5—H5C	107.9 (19)	H11A—C11—H11C	105.3 (19)
H5B—C5—H5C	107.2 (19)	H11B—C11—H11C	106.9 (19)
C3—C5—H5D	111 (3)	C8—C11—H11D	114 (3)
H5A—C5—H5D	57 (3)	H11A—C11—H11D	63 (3)
H5B—C5—H5D	56 (3)	H11B—C11—H11D	49 (3)
H5C—C5—H5D	138 (4)	H11C—C11—H11D	133 (4)
C3—C5—H5E	110 (3)	C8—C11—H11E	112 (3)
H5A—C5—H5E	136 (4)	H11A—C11—H11E	137 (3)
H5B—C5—H5E	60 (3)	H11B—C11—H11E	65 (3)
H5C—C5—H5E	50 (3)	H11C—C11—H11E	46 (3)
H5D—C5—H5E	111 (2)	H11D—C11—H11E	110 (2)
C3—C5—H5F	103 (3)	C8—C11—H11F	105 (3)
H5A—C5—H5F	53 (3)	H11A—C11—H11F	47 (3)
H5B—C5—H5F	147 (3)	H11B—C11—H11F	140 (4)
H5C—C5—H5F	63 (3)	H11C—C11—H11F	63 (3)
H5D—C5—H5F	109 (2)	H11D—C11—H11F	108 (2)
H5E—C5—H5F	111 (2)	H11E—C11—H11F	107 (2)
O1—N1—O2	123.4 (2)	O3^ii—N2—O3	123.1 (3)
O1—N1—C1	118.73 (18)	O3^ii—N2—C6	118.44 (15)
O2—N1—C1	117.84 (19)	O3—N2—C6	118.44 (15)
C7—C6—C7^ii	126.6 (2)	O4—N3—O4^ii	123.1 (3)
C7—C6—N2	116.68 (12)	O4—N3—C9	118.46 (13)
C7^ii—C6—N2	116.68 (12)	O4^ii—N3—C9	118.46 (13)
C3^i—C1—C2—C3	−0.1 (3)	C6—C7—C8—C9	−0.9 (2)
N1—C1—C2—C3	−179.22 (16)	C10—C7—C8—C9	179.97 (17)
C3^i—C1—C2—C4	−179.4 (2)	C6—C7—C8—C11	178.59 (16)
N1—C1—C2—C4	1.5 (3)	C10—C7—C8—C11	−0.5 (3)
C1—C2—C3—C1^i	0.1 (3)	C7—C8—C9—C8^ii	0.48 (12)
C4—C2—C3—C1^i	179.4 (2)	C11—C8—C9—C8^ii	−179.0 (2)
C1—C2—C3—C5	−179.37 (18)	C7—C8—C9—N3	−179.52 (12)
C4—C2—C3—C5	−0.1 (3)	C11—C8—C9—N3	1.0 (2)
C3^i—C1—N1—O1	86.5 (3)	C7—C6—N2—O3^ii	104.49 (17)
C2—C1—N1—O1	−94.3 (3)	C7^ii—C6—N2—O3^ii	−75.51 (17)
C3^i—C1—N1—O2	−93.5 (3)	C7—C6—N2—O3	−75.51 (17)
C2—C1—N1—O2	85.7 (3)	C7^ii—C6—N2—O3	104.49 (17)
C7^ii—C6—C7—C8	0.48 (12)	C8^ii—C9—N3—O4	−85.58 (15)
N2—C6—C7—C8	−179.52 (12)	C8—C9—N3—O4	94.42 (15)
C7^ii—C6—C7—C10	179.6 (2)	C8^ii—C9—N3—O4^ii	94.42 (15)
N2—C6—C7—C10	−0.4 (2)	C8—C9—N3—O4^ii	−85.58 (15)

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