Hexaaqua­zinc(II) dipicrate trihydrate

In the crystal structure of the title compound, [Zn(H₂O)₆](C₆H₂N₃O₇)₂·3H₂O, the zinc cation complexes and picrate anions are stacked separately, extending along the b axis. No picrate species ligate to the metal cation. This lack of picrate coordination is atypical among metal picrate salts. We speculate that the size of the metal–aqua complex as related to the inter­molecular distance of the picrate anions in the π stack can be a measure of the formation of such separated stacks in the crystal structures of divalent metal complexes with picrate anions. Picrate ions are linked to each other with short inter­molecular C...C contacts of 3.223 (6) and 3.194 (6) Å in the stack.

S1. Comment

Crystal structures of metal picrate salts that have been reported for the main-group, transition, lanthanide and actinide metals are classified into two groups according to the coordination structure of the metal cation and the picrate anion (Harrowfield, 1996). Most of the salts belong to the first group, where the picrate anion can bind directly to the metal atom via a coordinate and/or ionic bonds. In the second group, the water molecules are coordinated instead of the picrate ions to form an aqua complex cation with the metal. These are rather exceptional, and so far only three examples have been reported, viz. hexaaquamagnesium dipicrate trihydrate (Harrowfield et al., 1995), tris(µ-hydroxo)hexaaquatriberyllium tris(picrate) hexahydrate (Cecconi et al., 1998) and hexaaquairon dipicrate dihydrate (Honda et al., 2003). The coordination mode may be determined according to the balance of the picrate anions between the metal coordination and its stacking energy (Harrowfield, 1996). Picrate anions tend to stack in an almost parallel manner to their molecular planes, regardless of whether the phenolate group is coordinated to the metal. The intermolecular interaction energy of the π stack is considered to be comparable to the difference between the coordination bond energies of the picrate anion and aqua ligand to the metal cation. The second type of structure will be selected when the π-stack energy overcomes the coordination bond energy of the picrate ion to the metal, which thus displaces water. The coordinate structure is said to be controlled by the π-stack packing force. Thus, a further investigation of the crystal structures of metal picrates should contribute to the systematic understanding of the relationship between the structure formation and the intermolecular interaction. The crystal structure of a new 'no-picrate-coordination' complex, hexaaquazinc(II) dipicrate trihydrate, (I), is presented here and compared with those of other metal picrates.

Fig. 1 shows the molecular structures of the hexaaquazinc cation and picrate anions, and selected bond lengths are summarized in Table 1. Six water molecules are coordinated to the central metal atom and no picrate species ligate to the metal atom. The crystal structure as projected along the b axis is shown in Fig. 2. The unit cell contains four zinc cations and eight picrate anions. The cation complexes and picrate anions form separate stacks that extend along the b axis, and stacks consisting of the same species are aligned along the a axis. Picrate anions related through 2₁ screw symmetry stack in a head-to-tail manner, with the molecular planes almost parallel to the ac plane.

Similar packing motifs are observed in the Mg and Fe salts. In particular, the crystal structure of the Mg salt is similar to that of the present Zn salt. The monoclinic space group of P2₁/c for the Mg salt is similar to that of P2₁/n for the Zn salt, with a different direction of the glide symmetry. The unit-cell parameters [a = 15.023 (3) Å, b = 6.718 (4) Å, c = 26.516 (2) Å, β = 109.55 (1)° and V = 2522 ų] are similar to those of the Zn salt, with a reversed setting of a and c. The number of solvent water molecules in the unit cell (12) is also the same. The Fe salt crystallizes in a different space group (orthorhombic, Pccn) and the size of the unit cell is smaller [a = 25.248 (2) Å, b = 7.1136 (7) Å, c = 13.1993 (9) Å and V = 2370.7 (3) ų], partly because of the small number of solvent molecules in the unit cell (8). The average M—O bond distance for the Zn complex is 2.09 (2) Å. This value is close to the distance of 2.06 (1) Å for the Mg complex and is slightly shorter than that for the Fe complex [2.12 (4) Å]. On the other hand, the Be salt adopts a structure that is different from the other three salts in the group. The metals form a trimeric cation, the picrate anions stack in a head-to-head and slipped parallel manner, and the cation and picrate stacks do not align to each other.

Fig. 3 illustrates the molecular stack of the picrate anions of the Zn salt when viewed down the c axis. The anions in the stack are linked to each other via short intermolecular contacts of 3.223 (6) and 3.194 (6) Å for C3···C11ⁱ and C5···C9ⁱⁱ, respectively [symmetry codes: (i) -x, -y + 1, -z + 1; (ii) -x, -y, -z + 1]. Similar short C···C contacts in the stack are found in both the Mg salt (3.21 and 3.25 Å) and the Fe salt (3.06 and 3.08 Å). Successive anions of the stack are almost parallel to one another, with a dihedral angle between phenyl planes of 6.5 (1)°. This value is close to the dihedral angle of 6.3° in the Mg salt. In the Fe salt, instead, the planes are not parallel to one another, subtending a much larger dihedral angle (24.7°). An intermolecular repulsion would be too large to keep the two planes parallel with very short contacts of ca 3.1 Å. The π-stack contiguities of these salts are assumed to be similar when an `average distance' between two phenyl planes, which is estimated by calculating the average distance of the C atoms in one phenyl ring from the least-square plane formed by the C atoms in the other molecule, is used to compare them. The average distances for the Zn, Mg and Fe salts are 3.33 and 3.36, 3.35 and 3.36, and 3.45 and 3.50 Å, respectively. The phenyl planes of the three independent picrate anions in the Be salt are almost parallel to each other, since the dihedral angles are all less than 2°, and the estimated average distances are 3.40, 3.46 and 3.51 Å. A high level ab-initio molecular orbital calculation has revealed that the optimal intermolecular distance for benzene molecules is 3.5 Å at a slipped-parallel orientation (Tsuzuki et al., 2002). The average distances of the juxtaposed π-conjugated systems in the picrate stack seem to be slightly shorter than the most stable distance of benzene rings. An attractive electrostatic force due to a charge distribution introduced by the –NO₂ and –O^- groups could contribute to the building up of the close π stacks.

The closest metal–metal distances between the aqua complexes in the Zn, Mg and Fe salts correspond to the b axis lengths of their crystal lattice (6.69, 6.72 and 7.11 Å, respectively), that is, they are all approximately 7 Å and close to double the intermolecular spacings of the picrate anions in the π-stacks. This ratio of the intermolecular spacings is consistent with the chemical stoichiometry ratio of the divalent metal cation to the monovalent picrate anion. We speculate that such intermolecular spacing of the aqua complex may be a measure of the formation of the crystal packing with separate stacks of aqua complexes and picrate anions in the divalent metal complex salts. For the Zn–, Mg– and Fe–aqua complexes, the intermolecular spacing is adequate to form the separate stack structure. On the other hand, when the intermolecular spacing is significantly larger than 7 Å because of the large size of the aqua complex, the segregated stack structure should become unstable and the picrate anion may develop a tendency to become coordinated to the metal by eliminating the aqua ligand.

In order to estimate the size of the aqua complex we assume that the average M—O bond distance is the approximate size of the aqua-complex radius. The size of the complex is obtained by doubling the M—O distance. This value does not take the H atoms of the aqua ligand into account but can be used to compare the size of other metal–aqua complexes by using the reported atomic coordinates, some of which do not contain accurate information on the positions of the H atoms. The sizes of the Zn–, Mg– and Fe–aqua complexes are thus estimated to be 4.17, 4.12 and 4.23 Å, respectively. They are all approximately 4 Å and adjacent complexes have an intermolecular separation of ca 3 Å. This separation is expected to be an optimal value for the adjacent complexes to be energetically stable. Most of the metal cations in the picrate-coordinated group of divalent-metal picrate salts that have been reported have a large ionic radius, and the minimum metal—O(ligand) distance is 2.46 Å for the Ca^II salts (Diakiw et al., 1979). The size of the Ca–aqua complex would be approximately 5 Å, resulting in an intermolecular spacing of ca 8 Å, much larger than 7 Å. Although the M—O distance is 2.11 Å in the trivalent cation Sc salt, some picrate anions are directly bound to the metal (Harrowfield, et al., 1994). The separate π-stack orientation would be unfavorable in terms of the electrostatic interaction energy between such a trivalent cation and the counter-anions. The cation charge would be considered as another factor for determining the picrate binding to the cation, as previously discussed (Harrowfield, 1996; Cecconi et al., 1998).

Variable-temperature measurements from 300 K down to 95 K were also conducted for the Zn salt and showed a linear decrease of the lattice parameters. The thermal expansion coefficients for a, b, c, β and V were 1.32 × 10^-5, 9.90 × 10^-5, 2.53 × 10^-5, 6.57 × 10^-6 and 1.34 × 10 ^-4 K^-1, respectively. The value for V is close to the value of 1.30 × 10 ^-4 K^-1 for the Fe salt. Compared with the images observed at 300 K, the diffraction photographs at 95 K did not show any new appearances of diffraction spots or any diminution of existing spots. These results imply that the crystal is isomorphous between room temperature and 95 K. However, the diffraction spots disappeared and a powder diffraction pattern was observed at above 300 K. The d values of the diffraction lines were not consistent with the values that were estimated with the cell parameters of the single-crystal phase and indicated the occurrence of a phase transition.

A differential scanning calorimetry and thermal gravimetry analysis confirmed that the elimination of solvent water molecules begins at approximately this temperature (Matsukawa et al., 2003). The high-temperature phase is stable below the phase-transition temperature under a dry environment on cooling but returns to the low-temperature phase rapidly on addition of water to the powder sample. The iron salts also exhibited a similar phase transition at ca 330 K, accompanied by the loss of two water solvet molecules from the unit cell. Note that the powder patterns of the non-water-solvented phases of the iron and zinc salts are almost identical to one another. The determination of the structure from the powder pattern of the high-temperature phase will be reported in the near future.

Related literature

For related literature, see: Cecconi et al. (1998); Diakiw et al. (1979); Harrowfield (1996); Harrowfield et al. (1994, 1995); Honda et al. (2003); Matsukawa et al. (2003); Tsuzuki et al. (2002).

S2. Experimental

The synthesis of the title compound was reported by Matsukawa et al. (2003 or??2002). Single crystals were prepared by recrystallization from an aqueous solution.

S3. Refinement

The H atoms in the picrate anions were placed at calculated positions (C—H = 0.96 Å) and fixed during the final refinement, with U_iso(H) values of 1.5U_eq of the attached C atoms. Those in water molecules could not be reliably found in difference maps and were accordingly omitted from the model. However, short intermolecular contacts of O atoms between the water molecules and picrate anions suggest a complex hydrogen-bonding interaction between them.

Computing details

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software; data reduction: TEXSAN (Molecular Structure Corporation & Rigaku Corporation, 2000); program(s) used to solve structure: SHELXS86 (Sheldrick, 1985); program(s) used to refine structure: TEXSAN; molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: TEXSAN.

Figures

	Fig. 1. A displacement ellipsoid diagram (50% probability) of the title compound, with the atomic labelling.
	Fig. 2. The crystal structure, viewed along the b axis. Dashed lines depict intermolecular short contacts with O···O distances within 2.8 Å, suggesting hydrogen-bond formation.
	Fig. 3. The molecular stack of picrate anions, viewed along the c axis. Dashed lines indicate short intermolecular contacts with C···C distances within 3.3 Å.

Hexaaquazinc(II) dipicrate trihydrate

Crystal data

[Zn(H2O)6](C6H2N3O7)2·3H2O	F(000) = 1400.0
Mr = 683.71	Dx = 1.810 Mg m^−3 Dm = 1.81 Mg m^−3 Dm measured by CH2Br2–CH2Cl2 floatation
Monoclinic, P21/n	Mo Kα radiation, λ = 0.7107 Å
Hall symbol: -P 2yn	Cell parameters from 20 reflections
a = 25.711 (2) Å	θ = 25.0–29.8°
b = 6.6934 (4) Å	µ = 1.10 mm^−1
c = 15.007 (1) Å	T = 296 K
β = 103.656 (6)°	Prism, yellow
V = 2509.5 (3) Å^3	0.64 × 0.28 × 0.16 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	3619 reflections with F^2 > 2.0σ(F^2)
Radiation source: Nonius sealed tube	Rint = 0.015
Graphite monochromator	θmax = 27.5°
ω scans	h = −33→32
Absorption correction: ψ scan (North et al., 1968)	k = −2→8
Tmin = 0.732, Tmax = 0.839	l = −7→19
6370 measured reflections	3 standard reflections every 60 min
5771 independent reflections	intensity decay: −0.1%

Refinement

Refinement on F^2	w = 1/[σ^2(Fo^2) + {0.05[Max(Fo^2,0) + 2Fc^2]/3}^2]
R[F^2 > 2σ(F^2)] = 0.049	(Δ/σ)max = 0.0003
wR(F^2) = 0.134	Δρmax = 0.79 e Å^−3
S = 1.31	Δρmin = −0.48 e Å^−3
5771 reflections	Extinction correction: type 2 Gaussian isotropic [Zachariasen, W. H. (1967). Acta Cryst. 23, 558–564.]
380 parameters	Extinction coefficient: 0.0028 (7)
H-atom parameters not refined

Special details

Refinement. Refinement using reflections with F² > -10.0 σ(F²). The weighted R-factor (wR) and goodness of fit (S) are based on F². R-factor (gt) are based on F. The threshold expression of F² > 2.0 σ(F²) is used only for calculating R-factor (gt).

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

	x	y	z	Uiso*/Ueq
Zn1	0.25495 (2)	0.05002 (8)	0.02670 (3)	0.0303 (1)
O1	0.13590 (10)	0.0757 (5)	0.3599 (2)	0.0386 (8)
O2	0.0966 (1)	0.0362 (7)	0.5122 (2)	0.061 (1)
O3	0.0238 (1)	0.2008 (6)	0.5005 (2)	0.0527 (10)
O4	−0.1133 (1)	0.0957 (6)	0.2283 (2)	0.054 (1)
O5	−0.0925 (1)	0.0632 (6)	0.0990 (2)	0.0533 (10)
O6	0.0951 (1)	−0.0552 (7)	0.0992 (2)	0.065 (1)
O7	0.1448 (1)	0.1620 (6)	0.1852 (2)	0.059 (1)
O8	0.1455 (1)	0.4049 (5)	0.8770 (2)	0.0385 (8)
O9	0.0999 (1)	0.5026 (6)	1.0214 (2)	0.058 (1)
O10	0.0317 (1)	0.3090 (6)	1.0087 (2)	0.058 (1)
O11	−0.1018 (1)	0.4130 (6)	0.7301 (2)	0.058 (1)
O12	−0.0783 (1)	0.4344 (7)	0.6019 (2)	0.063 (1)
O13	0.1117 (1)	0.5088 (6)	0.6097 (2)	0.058 (1)
O14	0.1594 (1)	0.3053 (5)	0.7068 (2)	0.052 (1)
O15	0.3033 (1)	0.2889 (5)	0.0132 (2)	0.0427 (9)
O16	0.3118 (1)	−0.1537 (5)	0.0055 (2)	0.0435 (9)
O17	0.2254 (1)	0.0549 (5)	−0.1142 (2)	0.0386 (8)
O18	0.2039 (1)	−0.1801 (5)	0.0457 (2)	0.052 (1)
O19	0.1968 (1)	0.2590 (5)	0.0451 (2)	0.0367 (8)
O20	0.2867 (1)	0.0524 (6)	0.1692 (2)	0.0548 (10)
O21	0.2442 (1)	0.0434 (5)	0.3236 (2)	0.0461 (9)
O22	0.3059 (1)	0.4014 (5)	0.8427 (2)	0.0416 (8)
O23	0.2808 (1)	0.1726 (5)	0.6826 (2)	0.0437 (9)
N1	0.0559 (1)	0.1112 (6)	0.4664 (2)	0.0360 (10)
N2	−0.0804 (1)	0.0777 (5)	0.1824 (2)	0.0320 (9)
N3	0.1053 (1)	0.0540 (6)	0.1656 (2)	0.0394 (10)
N4	0.0627 (1)	0.4077 (6)	0.9757 (2)	0.0374 (10)
N5	−0.0678 (1)	0.4243 (6)	0.6853 (2)	0.039 (1)
N6	0.1200 (1)	0.4111 (5)	0.6803 (2)	0.0354 (10)
C1	0.0868 (1)	0.0774 (6)	0.3210 (2)	0.0268 (9)
C2	0.0437 (1)	0.0911 (6)	0.3674 (2)	0.0265 (10)
C3	−0.0099 (1)	0.0950 (5)	0.3233 (2)	0.0260 (9)
C4	−0.0244 (1)	0.0774 (6)	0.2290 (2)	0.0260 (9)
C5	0.0137 (1)	0.0599 (6)	0.1778 (2)	0.0269 (9)
C6	0.0667 (1)	0.0648 (6)	0.2226 (2)	0.0272 (9)
C7	0.0974 (1)	0.4124 (6)	0.8337 (2)	0.0272 (10)
C8	0.0523 (1)	0.4137 (6)	0.8759 (2)	0.0270 (10)
C9	−0.0004 (1)	0.4147 (6)	0.8292 (3)	0.030 (1)
C10	−0.0124 (1)	0.4224 (6)	0.7349 (3)	0.0292 (10)
C11	0.0274 (2)	0.4280 (6)	0.6866 (2)	0.0300 (10)
C12	0.0801 (1)	0.4186 (6)	0.7350 (2)	0.0278 (10)
H1	−0.0369	0.1097	0.3574	0.0393*
H2	0.0033	0.0447	0.1124	0.0405*
H3	−0.0284	0.4101	0.8616	0.0456*
H4	0.0185	0.4392	0.6210	0.0456*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.0240 (2)	0.0400 (3)	0.0263 (2)	0.0010 (2)	0.0046 (1)	0.0021 (2)
O1	0.026 (1)	0.061 (2)	0.028 (1)	−0.002 (1)	0.005 (1)	−0.003 (1)
O2	0.047 (2)	0.108 (3)	0.025 (1)	0.009 (2)	0.003 (1)	0.010 (2)
O3	0.054 (2)	0.071 (2)	0.037 (2)	−0.005 (2)	0.020 (1)	−0.018 (2)
O4	0.026 (1)	0.087 (3)	0.050 (2)	−0.001 (2)	0.011 (1)	−0.004 (2)
O5	0.038 (2)	0.084 (3)	0.032 (1)	0.006 (2)	−0.004 (1)	0.000 (2)
O6	0.057 (2)	0.101 (3)	0.044 (2)	0.005 (2)	0.024 (2)	−0.025 (2)
O7	0.037 (2)	0.099 (3)	0.047 (2)	−0.018 (2)	0.021 (1)	0.002 (2)
O8	0.027 (1)	0.055 (2)	0.033 (1)	0.001 (1)	0.006 (1)	0.005 (1)
O9	0.045 (2)	0.095 (3)	0.030 (1)	0.003 (2)	0.001 (1)	−0.015 (2)
O10	0.067 (2)	0.073 (3)	0.042 (2)	0.004 (2)	0.025 (2)	0.019 (2)
O11	0.027 (2)	0.087 (3)	0.058 (2)	0.006 (2)	0.006 (1)	0.006 (2)
O12	0.046 (2)	0.095 (3)	0.037 (2)	0.001 (2)	−0.011 (1)	−0.003 (2)
O13	0.060 (2)	0.081 (3)	0.037 (2)	−0.009 (2)	0.020 (1)	0.013 (2)
O14	0.044 (2)	0.058 (2)	0.059 (2)	0.012 (2)	0.024 (2)	−0.005 (2)
O15	0.043 (2)	0.052 (2)	0.034 (2)	−0.019 (2)	0.010 (1)	−0.003 (1)
O16	0.034 (2)	0.052 (2)	0.046 (2)	0.013 (1)	0.013 (1)	0.010 (2)
O17	0.033 (1)	0.050 (2)	0.029 (1)	−0.003 (1)	0.000 (1)	−0.003 (1)
O18	0.033 (2)	0.050 (2)	0.073 (2)	−0.004 (2)	0.012 (2)	0.015 (2)
O19	0.028 (1)	0.045 (2)	0.039 (2)	0.006 (1)	0.011 (1)	0.002 (1)
O20	0.032 (1)	0.103 (3)	0.027 (1)	0.001 (2)	0.002 (1)	0.009 (2)
O21	0.047 (2)	0.050 (2)	0.044 (2)	0.003 (2)	0.015 (1)	−0.001 (2)
O22	0.041 (2)	0.046 (2)	0.040 (2)	−0.004 (1)	0.014 (1)	0.005 (1)
O23	0.044 (2)	0.038 (2)	0.048 (2)	0.002 (1)	0.007 (1)	0.002 (1)
N1	0.035 (2)	0.048 (2)	0.026 (2)	−0.011 (2)	0.009 (1)	−0.003 (1)
N2	0.026 (2)	0.034 (2)	0.034 (2)	0.001 (1)	0.002 (1)	0.002 (1)
N3	0.034 (2)	0.060 (2)	0.027 (2)	0.006 (2)	0.013 (1)	0.007 (2)
N4	0.037 (2)	0.049 (3)	0.026 (2)	0.015 (2)	0.008 (1)	0.002 (2)
N5	0.030 (2)	0.037 (2)	0.046 (2)	0.003 (2)	0.000 (1)	−0.003 (2)
N6	0.037 (2)	0.040 (2)	0.032 (2)	−0.008 (2)	0.013 (1)	−0.007 (2)
C1	0.026 (2)	0.029 (2)	0.025 (2)	−0.001 (2)	0.006 (1)	−0.001 (2)
C2	0.029 (2)	0.031 (2)	0.020 (2)	−0.002 (2)	0.007 (1)	−0.001 (1)
C3	0.028 (2)	0.024 (2)	0.029 (2)	−0.001 (1)	0.011 (1)	−0.001 (1)
C4	0.025 (2)	0.023 (2)	0.029 (2)	−0.001 (2)	0.005 (1)	−0.001 (2)
C5	0.031 (2)	0.027 (2)	0.023 (2)	−0.001 (2)	0.007 (1)	0.000 (2)
C6	0.028 (2)	0.031 (2)	0.025 (2)	−0.002 (2)	0.011 (1)	0.000 (2)
C7	0.025 (2)	0.028 (2)	0.028 (2)	0.001 (2)	0.006 (1)	0.002 (2)
C8	0.029 (2)	0.030 (2)	0.023 (2)	0.004 (2)	0.007 (1)	−0.001 (2)
C9	0.027 (2)	0.029 (2)	0.034 (2)	0.003 (2)	0.009 (1)	0.000 (2)
C10	0.025 (2)	0.025 (2)	0.034 (2)	0.002 (2)	0.001 (1)	−0.001 (2)
C11	0.038 (2)	0.026 (2)	0.024 (2)	0.002 (2)	0.004 (1)	0.000 (2)
C12	0.032 (2)	0.026 (2)	0.027 (2)	−0.002 (2)	0.011 (1)	−0.003 (2)

Geometric parameters (Å, º)

Zn1—O15	2.065 (3)	N2—C4	1.445 (4)
Zn1—O16	2.078 (3)	N3—C6	1.457 (4)
Zn1—O17	2.071 (3)	N4—C8	1.457 (4)
Zn1—O18	2.087 (3)	N5—C10	1.442 (5)
Zn1—O19	2.112 (3)	N6—C12	1.457 (5)
Zn1—O20	2.101 (3)	C1—C2	1.445 (5)
O1—C1	1.259 (4)	C1—C6	1.447 (5)
O2—N1	1.217 (4)	C2—C3	1.381 (5)
O3—N1	1.224 (4)	C3—C4	1.382 (5)
O4—N2	1.218 (4)	C4—C5	1.384 (5)
O5—N2	1.220 (4)	C5—C6	1.369 (5)
O6—N3	1.214 (5)	C7—C8	1.446 (5)
O7—N3	1.226 (5)	C7—C12	1.443 (5)
O8—C7	1.255 (4)	C8—C9	1.370 (5)
O9—N4	1.216 (5)	C9—C10	1.377 (5)
O10—N4	1.226 (5)	C10—C11	1.387 (5)
O11—N5	1.224 (4)	C11—C12	1.380 (5)
O12—N5	1.218 (5)	C3—H1	0.959
O13—N6	1.220 (4)	C5—H2	0.960
O14—N6	1.222 (4)	C9—H3	0.960
N1—C2	1.451 (4)	C11—H4	0.960
O1···O16^i	2.807 (4)	O8···O17^ix	3.098 (4)
O1···O15^ii	2.889 (4)	O9···O19^ix	2.930 (4)
O1···O21	2.968 (4)	O10···O10^xi	3.012 (8)
O2···O22^iii	3.044 (4)	O10···N4^xi	3.132 (5)
O2···O15^ii	3.157 (4)	O10···N3^ix	3.151 (5)
O2···O16^i	3.197 (5)	O10···C5^ix	3.160 (5)
O3···O3^iv	2.951 (7)	O11···O20^xii	2.806 (4)
O3···N1^iv	3.046 (5)	O12···O13^xiii	3.111 (4)
O3···C11	3.163 (5)	O12···O16^xii	3.209 (4)
O3···O13	3.209 (5)	O13···O16^i	3.107 (4)
O4···O22^v	2.991 (4)	O14···O22^iii	2.995 (4)
O4···O23^v	3.067 (4)	O14···O23^x	3.156 (5)
O4···O17^vi	3.149 (4)	O15···O22^vii	2.683 (4)
O4···O14^iv	3.178 (5)	O17···O23^ii	2.748 (4)
O5···O6^vi	2.960 (4)	O18···O21^ii	2.796 (5)
O6···O10^vii	3.065 (6)	O19···O21^i	2.897 (4)
O6···O9^viii	3.194 (6)	O20···O21	2.787 (4)
O6···O18	3.198 (4)	O22···O23	2.793 (4)
O7···O19	2.821 (4)	O22···O23^x	2.829 (4)
O7···O21	2.995 (4)	C3···C11^xiii	3.223 (6)
O8···O19^ix	2.737 (4)	C5···C9^iv	3.194 (6)
O8···O23^x	2.900 (4)
O15—Zn1—O16	91.8 (1)	C2—C1—C6	111.4 (3)
O15—Zn1—O17	88.4 (1)	N1—C2—C1	119.7 (3)
O15—Zn1—O18	176.4 (1)	N1—C2—C3	116.0 (3)
O15—Zn1—O19	87.8 (1)	C1—C2—C3	124.3 (3)
O15—Zn1—O20	89.8 (1)	C2—C3—C4	119.1 (3)
O16—Zn1—O17	87.5 (1)	N2—C4—C3	119.5 (3)
O16—Zn1—O18	91.4 (1)	N2—C4—C5	119.1 (3)
O16—Zn1—O19	178.7 (1)	C3—C4—C5	121.4 (3)
O16—Zn1—O20	92.4 (1)	C4—C5—C6	118.5 (3)
O17—Zn1—O18	93.4 (1)	N3—C6—C1	118.2 (3)
O17—Zn1—O19	91.3 (1)	N3—C6—C5	116.5 (3)
O17—Zn1—O20	178.1 (1)	C1—C6—C5	125.3 (3)
O18—Zn1—O19	89.1 (1)	O8—C7—C8	124.6 (3)
O18—Zn1—O20	88.4 (1)	O8—C7—C12	123.9 (3)
O19—Zn1—O20	88.8 (1)	C8—C7—C12	111.5 (3)
O2—N1—O3	122.8 (3)	N4—C8—C7	118.6 (3)
O2—N1—C2	119.3 (3)	N4—C8—C9	116.4 (3)
O3—N1—C2	118.0 (3)	C7—C8—C9	125.0 (3)
O4—N2—O5	123.0 (3)	C8—C9—C10	118.8 (3)
O4—N2—C4	118.3 (3)	N5—C10—C9	119.1 (3)
O5—N2—C4	118.7 (3)	N5—C10—C11	119.3 (3)
O6—N3—O7	123.9 (3)	C9—C10—C11	121.6 (3)
O6—N3—C6	117.9 (4)	C10—C11—C12	118.6 (3)
O7—N3—C6	118.1 (4)	N6—C12—C7	119.4 (3)
O9—N4—O10	123.5 (4)	N6—C12—C11	116.1 (3)
O9—N4—C8	119.6 (3)	C7—C12—C11	124.6 (3)
O10—N4—C8	116.8 (3)	C2—C3—H1	120.8
O11—N5—O12	123.6 (3)	C4—C3—H1	120.2
O11—N5—C10	117.4 (3)	C4—C5—H2	120.9
O12—N5—C10	118.9 (3)	C6—C5—H2	120.6
O13—N6—O14	123.6 (3)	C8—C9—H3	120.7
O13—N6—C12	117.9 (4)	C10—C9—H3	120.5
O14—N6—C12	118.4 (3)	C10—C11—H4	120.9
O1—C1—C2	125.2 (3)	C12—C11—H4	120.5
O1—C1—C6	123.4 (3)
O1—C1—C2—N1	2.1 (6)	O13—N6—C12—C11	36.7 (5)
O1—C1—C2—C3	179.2 (4)	O14—N6—C12—C7	36.8 (5)
O1—C1—C6—N3	−1.4 (6)	O14—N6—C12—C11	−142.1 (4)
O1—C1—C6—C5	177.8 (4)	N1—C2—C1—C6	−178.1 (3)
O2—N1—C2—C1	−30.6 (5)	N1—C2—C3—C4	179.8 (3)
O2—N1—C2—C3	152.0 (4)	N2—C4—C3—C2	178.9 (3)
O3—N1—C2—C1	150.7 (4)	N2—C4—C5—C6	178.4 (4)
O3—N1—C2—C3	−26.7 (5)	N3—C6—C1—C2	178.8 (4)
O4—N2—C4—C3	0.8 (5)	N3—C6—C5—C4	−177.6 (4)
O4—N2—C4—C5	−179.1 (4)	N4—C8—C7—C12	179.9 (3)
O5—N2—C4—C3	179.6 (4)	N4—C8—C9—C10	179.3 (3)
O5—N2—C4—C5	−0.3 (6)	N5—C10—C9—C8	−179.7 (4)
O6—N3—C6—C1	141.3 (4)	N5—C10—C11—C12	−177.6 (4)
O6—N3—C6—C5	−38.0 (6)	N6—C12—C7—C8	−177.8 (3)
O7—N3—C6—C1	−41.9 (6)	N6—C12—C11—C10	175.9 (4)
O7—N3—C6—C5	138.8 (4)	C1—C2—C3—C4	2.5 (6)
O8—C7—C8—N4	0.6 (6)	C1—C6—C5—C4	3.2 (6)
O8—C7—C8—C9	−177.6 (4)	C2—C1—C6—C5	−2.0 (6)
O8—C7—C12—N6	1.5 (6)	C2—C3—C4—C5	−1.2 (6)
O8—C7—C12—C11	−179.6 (4)	C3—C2—C1—C6	−1.0 (5)
O9—N4—C8—C7	39.3 (5)	C3—C4—C5—C6	−1.5 (6)
O9—N4—C8—C9	−142.4 (4)	C7—C8—C9—C10	−2.5 (6)
O10—N4—C8—C7	−142.5 (4)	C7—C12—C11—C10	−3.0 (6)
O10—N4—C8—C9	35.8 (5)	C8—C7—C12—C11	1.0 (5)
O11—N5—C10—C9	−2.1 (6)	C8—C9—C10—C11	0.3 (6)
O11—N5—C10—C11	177.8 (4)	C9—C8—C7—C12	1.8 (5)
O12—N5—C10—C9	178.8 (4)	C9—C10—C11—C12	2.3 (6)
O12—N5—C10—C11	−1.2 (6)	C9—C10—C11—C12	2.3 (6)
O13—N6—C12—C7	−144.3 (4)

Symmetry codes: (i) −x+1/2, y+1/2, −z+1/2; (ii) −x+1/2, y−1/2, −z+1/2; (iii) −x+1/2, y−1/2, −z+3/2; (iv) −x, −y, −z+1; (v) x−1/2, −y+1/2, z−1/2; (vi) −x, −y, −z; (vii) x, y, z−1; (viii) x, y−1, z−1; (ix) x, y, z+1; (x) −x+1/2, y+1/2, −z+3/2; (xi) −x, −y+1, −z+2; (xii) x−1/2, −y+1/2, z+1/2; (xiii) −x, −y+1, −z+1.