Unusual O-coordination of caffeine in tetra­kis([mu]-3,5-dinitro­benzoato-[kappa]²O:O')bis­[(caffeine-[kappa]O)copper(II)]

The title compound {systematic name: tetra­kis([mu]-3,5-dinitro­benzoato-[kappa]²O:O')bis­[(3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione-[kappa]O²)copper(II)]}, [Cu₂(C₇H₃N₂O₆)₄(C₈H₁₀N₄O₂)₂], consists of paddle-wheel dimeric tetra­kis([mu]-3,5-dinitro­benzoato-[kappa]²O:O')dicopper(II) units with O-coordinated caffeine mol­ecules in both apical positions. The entire dimeric mol­ecule lies on a tetra­gonal inversion axis, and thus one nitro­benzoate anion with one Cu atom in a special position belong to the independent part of the mol­ecule. The caffeine ligand bonded to the Cu atom is disordered on a local twofold non-crystallographic axis coincident with the axis. A [pi]-[pi] stacking inter­action is observed between the caffeine rings and adjacent symmetry-related benzene rings of the 3,5-dinitro­benzoate anions.

S1. Comment

Benzoates, especially salicylates and fenamates, are known to play an important role in human medicine. The preparation of new nitrosubstituted benzoatocopper complexes with different biologically active ligands, the study of their composition, stereochemistry, structure and spectroscopic properties, and of course the study of their biological activity, are the basis of our approach to studying these compounds.

The complex molecule of the title compound, (I) (Fig. 1), is located on an inversion axis 4, with both Cu atoms and atoms O7, C8 and C10 of the caffeine ligand on a twofold axis. Each Cu atom in the dimeric structure has a tetragonal–pyramidal coordination, with four carboxylate O atom (O1, O2 and their symmetry equivalents) in equatorial positions [Cu—O1 = 1.933 (2) Å and Cu—O2 = 1.983 (2) Å] and caffeine atom O7 in the apical position [Cu—O7 = 2.180 (2) Å]. The Cu···Cuⁱⁱ separation is 2.661 (1) Å [symmetry code: (ii) y − 1/4, 1/4 − x, 5/4 − z Please check added symmop], which is close to the Cu···Cu distance in the complex [Cu₃(C₇H₃N₂O₆)₆(CH₃OH)₂]_n (Hökelek et al., 1998). The Cu atoms are slightly displaced from the basal plane by 0.200 (1) Å toward the apical atom O7, and the τ parameter (Addison et al., 1984) of 0.16 implies tetragonal geometry.

The caffeine molecules are significantly planar; the dihedral angle between the pyrimidine and imidazole rings is 0°. These dihedral angles for the structures of other complexes with caffeine are in the range 0–5°. The dihedral angle is 0° only for complexes [Cu₂(µ-flufenamato-κ²O:O')₄(caffeine-κN)(H₂O)] (Melník et al., 1998) and [Cu₂(µ-CCl₃CO₂-κ²O:O')₄(caffeine-κN)₂].benzene (Horie et al., 1986).

Interactions between molecules of (I) are π–π stacking interactions (Fig. 2) (Janiak, 2000) between the caffeine rings and adjacent symmetry-related benzene rings of the 3,5-dinitrobenzoate anions at (−x, −y, −z + 1) and (x, y + 1/2, −z + 1); the distances between the caffeine and benzene planes are in the range 3.28–3.52 Å.

As a ligand, caffeine usually prefers an N atom as a donor atom, e.g. in copper(II) carboxylate complexes with caffeine of the formulae [Cu₂(µ-flufenamato-κ²O:O')₄(caffeine-κN)(H₂O)] (Melník et al., 1998) or [Cu₂(µ-RCO₂-κ²O:O')₄(caffeine-κN)₂], where RCO₂⁻ is the benzoate anion (Kawata et al., 1992), the naproxenate anion (Koman et al., 2000), the chloroacetate anion (Koreň et al., 1985), the o-iodobenzoate anion (Valach et al., 2001), the benzoylformate anion (Harada et al., 1997) or the trichloroacetate anion (Horie et al., 1986). The Cu···Cu separations and Cu—N_ap(caffeine) bond distances in these complexes are in the ranges 2.633–2.852 and 2.239–2.116 Å, respectively. The O atom was found to participate in coordination only in the complex {[Cu₂(µ-CCl₃CO₂-κ²O:O')₄(µ-caffeine-κ²N:O)].2toluene}_n, which contains caffeine as a bridging ligand (Uekusa et al., 1992). It is interesting that the bonding of caffeine via an O atom in the title compound results in a smaller Cu-to-basal plane distance compared with those compounds with caffeine as an N-donor ligand [0.223 (Melník et al., 1998), 0.204 (Kawata et al., 1992), 0.217 (Koman et al., 2000), 0.236 (Koreň et al., 1985), 0.236 (Valach et al., 2001), 0.259 (Harada et al., 1997) or 0.315 Å (Horie et al., 1986).

Complex (I) is also unusual for the manner of bonding adopted by the 3,5-dinitrobenzoate anion. This anion prefers a monodentate or ionic bonding manner, and there is only one example of a bidentate bridging bonding mode forming copper(II) acetate-like dimers in 3,5-dinitrobenzoatocopper(II) complexes with formula [Cu₃(C₇H₃N₂O₆)₆(CH₃OH)₂]_n (Hökelek et al., 1998), and in this case (O-donor apical ligand) the Cu atom is displaced from the basal plane by 0.195 Å.

S2. Experimental

Caffeine (0.5 mmol) was added to copper(II) acetate (1 mmol) in aqueous solution (Volume?). 3,5-Dinitrobenzoic acid (2 mmol) was then added. The powdery blue product was filtered off, washed with water and dried at room temperature. Blue crystals of (I) suitable for X-ray analysis were obtained from the mother liquor after a few weeks by slow room-temperature crystallization.

S3. Refinement

Discrete positional disorder of the caffeine ligands is observed. Molecules of (I) lie around a 4 inversion axis. Atoms Cu, O7, C8 and C10 lie in special positions on the twofold rotation axis and have occupancy factors of 0.5 in the asymmetric unit. Fig. 1 shows the molecular structure of (I). Atoms which have full occupancy in complete molecules are drawn with solid lines. Atoms which have 0.5 occupancy in parts A or B alongside the twofold rotation axis are drawn with open or open dashed lines. Atoms N from the caffeine ligand in part A and atom O8 from the caffeine ligand in mirror part B lie in the same positions and were constrained by EXYZ and EADP with occupancy factors of 0.5. In part A, the full caffeine ligand consists of atoms O7, C8, C9, N3, N4, N5, C11 and C13, atoms in inversion C9ⁱ, N3ⁱ, C13ⁱ, C12ⁱ and O8ⁱ, and their parent H atoms. In part A [Part B?], the full molecule consists of atoms O7, C8, C9, N3, C12, O8 and C13, atoms in inversion C9ⁱ, N3ⁱ, C13ⁱ, N4ⁱ, N5ⁱ and C11ⁱ, and their parent H atoms. The remaining H atoms were positioned geometically, with C—H = 0.95 and 0.98 Å for aromatic and methyl H atoms, respectively, and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2003); cell refinement: CrysAlis RED (Oxford Diffraction, 2003); data reduction: CrysAlis RED; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL (Sheldrick, 1998); software used to prepare material for publication: enCIFer (Allen et al., 2004).

Figures

	Fig. 1. A perspective view of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. [Symmetry codes: (i) −x, 1/2 − y, z; (ii) y − 1/4, 1/4 − x, 5/4 − z].
	Fig. 2. The π–π stacking interactions (dashed lines) in the crystal structure of (I).

tetrakis(µ-3,5-dinitrobenzoato-κ²O:O')bis[(3,7-dihydro-1,3,7- trimethyl-1H-purine-2,6-dione-κO)copper(II)]}

Crystal data

[Cu2(C7H3N2O6)4(C8H10N4O2)2]	Dx = 1.790 Mg m^−3
Mr = 1359.96	Mo Kα radiation, λ = 0.71069 Å
Tetragonal, I41/a	Cell parameters from 6992 reflections
a = 12.900 (5) Å	θ = 3.2–35.0°
c = 30.330 (3) Å	µ = 0.96 mm^−1
V = 5047 (3) Å^3	T = 100 K
Z = 4	Block, blue
F(000) = 2760	0.24 × 0.12 × 0.11 mm

Data collection

Kuma KM-4 CCD area-detector diffractometer	5131 independent reflections
Radiation source: fine-focus sealed tube	2721 reflections with I > 2α(I)
Graphite monochromator	Rint = 0.067
ω scans	θmax = 35.0°, θmin = 3.2°
Absorption correction: analytical (CrysAlis RED; Oxford Diffraction, 2003)	h = −16→15
Tmin = 0.826, Tmax = 0.908	k = −17→20
19901 measured reflections	l = −47→39

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)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.078	H-atom parameters constrained
S = 1.01	w = 1/[σ^2(Fo^2) + (0.0207P)^2] where P = (Fo^2 + 2Fc^2)/3
5131 reflections	(Δ/σ)max < 0.001
216 parameters	Δρmax = 0.91 e Å^−3
0 restraints	Δρmin = −0.61 e Å^−3

Special details

Experimental. analytical numerical absorption using a multifaceted crystal model

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Cu	0.0000	0.2500	0.581135 (11)	0.00983 (9)
N1	0.29906 (13)	−0.19367 (13)	0.69899 (6)	0.0168 (4)
N2	0.26890 (13)	−0.19816 (14)	0.53733 (6)	0.0170 (4)
N3	0.04696 (12)	0.17070 (12)	0.44505 (5)	0.0133 (4)
N4	0.0177 (3)	0.2223 (3)	0.33284 (10)	0.0147 (8)	0.50
N5	0.09415 (12)	0.09653 (12)	0.37678 (6)	0.0213 (4)	0.50
O1	0.07869 (10)	0.12280 (10)	0.58494 (4)	0.0141 (3)
O2	0.12827 (11)	0.33175 (10)	0.59047 (4)	0.0139 (3)
O3	0.35451 (11)	−0.27110 (11)	0.69570 (5)	0.0229 (4)
O4	0.27634 (11)	−0.15046 (11)	0.73356 (4)	0.0193 (3)
O5	0.32022 (11)	−0.27824 (11)	0.53727 (5)	0.0238 (4)
O6	0.23465 (12)	−0.15658 (12)	0.50390 (5)	0.0245 (4)
O7	0.0000	0.2500	0.50926 (6)	0.0182 (4)
O8	0.09415 (12)	0.09653 (12)	0.37678 (6)	0.0213 (4)	0.50
C1	0.10335 (14)	0.08503 (14)	0.62227 (7)	0.0130 (4)
C2	0.16494 (14)	−0.01333 (14)	0.62103 (6)	0.0115 (4)
C3	0.19942 (15)	−0.05885 (15)	0.66000 (7)	0.0128 (4)
H3	0.1828	−0.0290	0.6878	0.015*
C4	0.25847 (15)	−0.14856 (16)	0.65753 (7)	0.0137 (5)
C5	0.28290 (15)	−0.19614 (16)	0.61797 (6)	0.0140 (5)
H5	0.3226	−0.2581	0.6169	0.017*
C6	0.24658 (16)	−0.14898 (16)	0.58017 (7)	0.0134 (4)
C7	0.18889 (15)	−0.05867 (15)	0.58075 (7)	0.0130 (4)
H7	0.1660	−0.0280	0.5540	0.016*
C8	0.0000	0.2500	0.46879 (9)	0.0133 (6)
C9	0.05002 (15)	0.16877 (15)	0.39868 (6)	0.0124 (4)
C10	0.0000	0.2500	0.37706 (9)	0.0114 (5)
C11	0.0709 (3)	0.1319 (3)	0.33348 (13)	0.0180 (9)	0.50
H11	0.0908	0.0957	0.3076	0.022*	0.50
C12	0.0154 (4)	0.2187 (3)	0.29438 (13)	0.0190 (10)*	0.50
H12A	0.0913	0.2162	0.2934	0.028*	0.50
H12B	−0.0107	0.2521	0.2676	0.028*	0.50
H12C	−0.0121	0.1480	0.2963	0.028*	0.50
C13	0.09496 (17)	0.08490 (16)	0.46926 (7)	0.0188 (5)
H13A	0.0678	0.0833	0.4994	0.028*
H13B	0.1703	0.0948	0.4701	0.028*
H13C	0.0789	0.0193	0.4545	0.028*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu	0.0110 (2)	0.0098 (2)	0.00861 (16)	0.00072 (18)	0.000	0.000
N1	0.0170 (10)	0.0134 (9)	0.0200 (10)	−0.0013 (8)	−0.0028 (8)	0.0053 (8)
N2	0.0161 (10)	0.0167 (10)	0.0182 (10)	−0.0020 (8)	0.0025 (8)	−0.0036 (8)
N3	0.0152 (9)	0.0130 (9)	0.0117 (9)	0.0001 (7)	0.0002 (7)	0.0000 (7)
N4	0.018 (2)	0.019 (2)	0.0075 (14)	−0.0003 (16)	−0.0010 (17)	0.0021 (14)
N5	0.0238 (9)	0.0179 (8)	0.0222 (9)	0.0051 (7)	0.0046 (8)	−0.0009 (8)
O1	0.0161 (8)	0.0127 (7)	0.0134 (8)	0.0034 (6)	0.0008 (6)	0.0006 (6)
O2	0.0132 (8)	0.0172 (8)	0.0114 (7)	−0.0032 (7)	−0.0013 (6)	−0.0014 (6)
O3	0.0264 (9)	0.0165 (8)	0.0258 (9)	0.0108 (7)	−0.0042 (7)	0.0043 (7)
O4	0.0234 (9)	0.0199 (8)	0.0146 (8)	0.0009 (7)	0.0000 (7)	0.0018 (7)
O5	0.0257 (9)	0.0188 (8)	0.0267 (9)	0.0075 (7)	0.0017 (7)	−0.0065 (7)
O6	0.0313 (9)	0.0286 (9)	0.0135 (8)	0.0064 (8)	0.0007 (7)	−0.0010 (7)
O7	0.0205 (12)	0.0244 (12)	0.0096 (10)	0.0033 (11)	0.000	0.000
O8	0.0238 (9)	0.0179 (8)	0.0222 (9)	0.0051 (7)	0.0046 (8)	−0.0009 (8)
C1	0.0092 (9)	0.0119 (9)	0.0179 (11)	−0.0017 (8)	−0.0002 (9)	0.0013 (9)
C2	0.0093 (9)	0.0100 (9)	0.0152 (10)	−0.0011 (7)	0.0010 (9)	0.0002 (9)
C3	0.0125 (10)	0.0131 (11)	0.0129 (11)	−0.0035 (9)	0.0002 (8)	0.0005 (8)
C4	0.0119 (10)	0.0134 (11)	0.0160 (11)	−0.0004 (9)	−0.0027 (9)	0.0037 (9)
C5	0.0117 (10)	0.0108 (10)	0.0195 (12)	0.0018 (8)	−0.0007 (9)	−0.0009 (9)
C6	0.0121 (10)	0.0130 (10)	0.0152 (10)	−0.0031 (9)	0.0017 (9)	−0.0021 (9)
C7	0.0115 (10)	0.0133 (10)	0.0140 (10)	−0.0018 (9)	−0.0007 (9)	0.0013 (9)
C8	0.0115 (15)	0.0183 (17)	0.0102 (14)	−0.0049 (14)	0.000	0.000
C9	0.0105 (10)	0.0146 (11)	0.0123 (11)	−0.0030 (9)	−0.0004 (8)	0.0002 (8)
C10	0.0121 (14)	0.0138 (14)	0.0084 (12)	−0.0005 (12)	0.000	0.000
C11	0.022 (2)	0.021 (2)	0.011 (2)	0.0007 (19)	0.0010 (18)	−0.0069 (18)
C13	0.0230 (12)	0.0185 (11)	0.0149 (11)	0.0030 (10)	0.0000 (9)	0.0038 (9)

Geometric parameters (Å, º)

Cu—O1^i	1.933 (2)	C1—O2^ii	1.256 (2)
Cu—O1	1.933 (2)	C1—C2	1.498 (3)
Cu—O2	1.983 (2)	C2—C7	1.389 (3)
Cu—O2^i	1.983 (2)	C2—C3	1.393 (3)
Cu—O7	2.180 (2)	C3—C4	1.388 (3)
Cu—Cu^ii	2.661 (1)	C3—H3	0.9500
N1—O4	1.223 (2)	C4—C5	1.384 (3)
N1—O3	1.233 (2)	C5—C6	1.380 (3)
N1—C4	1.481 (3)	C5—H5	0.9500
N2—O5	1.227 (2)	C6—C7	1.383 (3)
N2—O6	1.229 (2)	C7—H7	0.9500
N2—C6	1.474 (3)	C8—N3^i	1.390 (2)
N3—C8	1.390 (2)	C9—C10	1.394 (2)
N3—C9	1.407 (2)	C10—C9^i	1.394 (2)
N3—C13	1.465 (2)	C10—N4^i	1.407 (4)
N4—N4^i	0.848 (6)	C11—H11	0.9500
N4—C11	1.352 (5)	C12—N4^i	1.457 (4)
N4—C10	1.407 (4)	C12—H12A	0.9800
N4—C12^i	1.457 (4)	C12—H12B	0.9800
N5—C11	1.423 (4)	C12—H12C	0.9800
N5—C9	1.278 (2)	C13—H13A	0.9800
O1—C1	1.273 (2)	C13—H13B	0.9800
O2—C1^iii	1.256 (2)	C13—H13C	0.9800
O7—C8	1.227 (3)
O1^i—Cu—O1	173.16 (8)	C3—C2—C1	120.35 (18)
O1^i—Cu—O2	88.75 (6)	C4—C3—C2	118.75 (19)
O1—Cu—O2	90.27 (6)	C4—C3—H3	120.6
O1^i—Cu—O2^i	90.27 (6)	C2—C3—H3	120.6
O1—Cu—O2^i	88.75 (6)	C5—C4—C3	122.80 (19)
O2—Cu—O2^i	163.57 (8)	C5—C4—N1	118.78 (18)
O1^i—Cu—O7	93.42 (4)	C3—C4—N1	118.40 (18)
O1—Cu—O7	93.42 (4)	C6—C5—C4	116.59 (19)
O2—Cu—O7	98.21 (4)	C6—C5—H5	121.7
O2^i—Cu—O7	98.21 (4)	C4—C5—H5	121.7
O1^i—Cu—Cu^ii	86.58 (4)	C5—C6—C7	122.9 (2)
O1—Cu—Cu^ii	86.58 (4)	C5—C6—N2	118.44 (18)
O2—Cu—Cu^ii	81.79 (4)	C7—C6—N2	118.62 (19)
O2^i—Cu—Cu^ii	81.79 (4)	C6—C7—C2	119.06 (19)
O7—Cu—Cu^ii	180.0	C6—C7—H7	120.5
O4—N1—O3	125.29 (17)	C2—C7—H7	120.5
O4—N1—C4	117.66 (17)	O7—C8—N3	121.19 (11)
O3—N1—C4	117.04 (17)	O7—C8—N3^i	121.19 (12)
O5—N2—O6	124.06 (18)	N3—C8—N3^i	117.6 (2)
O5—N2—C6	117.97 (17)	N5—C9—C10	120.64 (19)
O6—N2—C6	117.97 (17)	N5—C9—N3	123.01 (18)
C8—N3—C9	122.88 (17)	C10—C9—N3	116.34 (18)
C8—N3—C13	118.72 (17)	C9—C10—C9^i	123.9 (3)
C9—N3—C13	118.39 (16)	C9—C10—N4	100.50 (16)
N4^i—N4—C11	177.8 (7)	C9^i—C10—N4	135.60 (19)
N4^i—N4—C10	72.45 (12)	C9—C10—N4^i	135.60 (19)
C11—N4—C10	106.7 (3)	C9^i—C10—N4^i	100.50 (16)
N4^i—N4—C12^i	53.25 (19)	N5—C11—N4	113.4 (3)
C11—N4—C12^i	127.6 (3)	N5—C11—H11	123.3
C10—N4—C12^i	125.7 (3)	N4—C11—H11	123.3
C11—N5—C9	98.7 (2)	N4^i—C12—H12A	109.5
C1—O1—Cu	120.60 (13)	N4^i—C12—H12B	109.5
C1^iii—O2—Cu	124.12 (13)	N4^i—C12—H12C	109.5
C8—O7—Cu	180.0	N3—C13—H13A	109.5
O2^ii—C1—O1	126.90 (17)	N3—C13—H13B	109.5
O2^ii—C1—C2	117.36 (18)	H13A—C13—H13B	109.5
O1—C1—C2	115.74 (18)	N3—C13—H13C	109.5
C7—C2—C3	119.86 (18)	H13A—C13—H13C	109.5
C7—C2—C1	119.79 (18)	H13B—C13—H13C	109.5
O1^i—Cu—O1—C1	−0.74 (14)	O6—N2—C6—C7	−0.3 (3)
O2—Cu—O1—C1	81.01 (14)	C5—C6—C7—C2	−0.8 (3)
O2^i—Cu—O1—C1	−82.59 (14)	N2—C6—C7—C2	178.19 (17)
O7—Cu—O1—C1	179.26 (13)	C3—C2—C7—C6	0.2 (3)
Cu^ii—Cu—O1—C1	−0.74 (13)	C1—C2—C7—C6	179.45 (17)
O1^i—Cu—O2—C1^iii	87.80 (15)	Cu—O7—C8—N3	−31 (49)
O1—Cu—O2—C1^iii	−85.43 (15)	Cu—O7—C8—N3^i	149 (85)
O2^i—Cu—O2—C1^iii	1.08 (14)	C9—N3—C8—O7	−178.97 (12)
O7—Cu—O2—C1^iii	−178.92 (14)	C13—N3—C8—O7	1.39 (17)
Cu^ii—Cu—O2—C1^iii	1.08 (14)	C9—N3—C8—N3^i	1.03 (12)
O1^i—Cu—O7—C8	−148 (85)	C13—N3—C8—N3^i	−178.61 (17)
O1—Cu—O7—C8	32 (49)	C11—N5—C9—C10	−0.5 (3)
O2—Cu—O7—C8	123 (49)	C11—N5—C9—N3	178.3 (2)
O2^i—Cu—O7—C8	−57 (85)	C8—N3—C9—N5	179.20 (15)
Cu^ii—Cu—O7—C8	0 (44)	C13—N3—C9—N5	−1.2 (3)
Cu—O1—C1—O2^ii	0.2 (3)	C8—N3—C9—C10	−2.0 (2)
Cu—O1—C1—C2	−179.58 (12)	C13—N3—C9—C10	177.67 (15)
O2^ii—C1—C2—C7	178.47 (17)	N5—C9—C10—C9^i	179.8 (2)
O1—C1—C2—C7	−1.8 (3)	N3—C9—C10—C9^i	0.93 (11)
O2^ii—C1—C2—C3	−2.3 (3)	N5—C9—C10—N4	−0.5 (2)
O1—C1—C2—C3	177.44 (17)	N3—C9—C10—N4	−179.3 (2)
C7—C2—C3—C4	0.8 (3)	N5—C9—C10—N4^i	0.2 (3)
C1—C2—C3—C4	−178.42 (18)	N3—C9—C10—N4^i	−178.7 (3)
C2—C3—C4—C5	−1.4 (3)	N4^i—N4—C10—C9	179.2 (5)
C2—C3—C4—N1	177.11 (17)	C11—N4—C10—C9	1.3 (3)
O4—N1—C4—C5	−179.87 (19)	C12^i—N4—C10—C9	−178.4 (4)
O3—N1—C4—C5	1.2 (3)	N4^i—N4—C10—C9^i	−1.1 (7)
O4—N1—C4—C3	1.6 (3)	C11—N4—C10—C9^i	−179.0 (2)
O3—N1—C4—C3	−177.33 (18)	C12^i—N4—C10—C9^i	1.3 (6)
C3—C4—C5—C6	0.9 (3)	C11—N4—C10—N4^i	−177.9 (8)
N1—C4—C5—C6	−177.60 (19)	C12^i—N4—C10—N4^i	2.4 (3)
C4—C5—C6—C7	0.2 (3)	C9—N5—C11—N4	1.4 (4)
C4—C5—C6—N2	−178.74 (18)	N4^i—N4—C11—N5	−69 (10)
O5—N2—C6—C5	−1.0 (3)	C10—N4—C11—N5	−1.8 (4)
O6—N2—C6—C5	178.72 (19)	C12^i—N4—C11—N5	177.9 (4)
O5—N2—C6—C7	179.96 (18)

Symmetry codes: (i) −x, −y+1/2, z; (ii) y−1/4, −x+1/4, −z+5/4; (iii) −y+1/4, x+1/4, −z+5/4.