Synchrotron structure determination of an [alpha]-Keggin doubly Pt^IV-substituted silicotungstate, (CH₆N₃)₈[[alpha]-SiPt₂W₁₀O₄₀]·6H₂O

The crystal structure of octaguanidinium [alpha]-silicodiplatino­decatungstate hexahydrate, (CH₆N₃)₈[[alpha]-SiPt₂W₁₀O₄₀]·6H₂O, has been analyzed via a high-energy X-ray diffraction experiment at the SPring-8 BL04B2 beamline. The title compound contains a novel [alpha]-Keggin heteropolyanion in which two of the addenda atoms are replaced by Pt atoms. W and Pt atoms occupy the same coordinates; the occupancy fractions are (W) and (Pt), and the [alpha]-Keggin anion has symmetry. The two types of W(Pt)-W(Pt) distance are in the ranges 3.3565 (4)-3.3704 (4) and 3.7033 (4)-3.7100 (4) Å, the four types of W(Pt)-O bond length are in the ranges 1.721 (5)-1.725 (5), 1.910 (5)-1.932 (5), 1.934 (5)-1.956 (5) and 2.339 (4)-2.348 (4) Å, and the Si-O bond length is 1.646 (4) Å.

S1. Comment

High-energy synchrotron-radiation X-ray diffraction experiments are advantageous for structure determinations of inorganic crystals that would show very large absorption coefficients when analyzed using Mo Kα radiation. With synchrotron radiation, systematic deviations of the diffraction intensities due to the effects of absorption and extinction are considerably reduced, leading to more accurate positional and displacement parameters for both the heavier and the lighter atoms in the crystal. This advantage has been demonstrated for the structure determinations of some isopolyoxotungstates (Ozeki, 2001; Ozeki et al., 2001). In the present study, we have applied this strategy to a structure determination of a heteropolyoxotungstate containing Pt^IV atoms.

The Pt^IV ion shows a very rich chemical behavior when it forms heteropolyoxometalates with the Anderson structure (Lee et al., 1983; Lee, et al., 1984, Lee & Sasaki, 1994; Lee, 1994; Joo et al., 1994). We presume that the diversity of the Pt^IV-containing heteropolyoxometalates is caused by the similarities in the oxidation states and the ionic radii of addenda atoms (Pt⁴⁺ = 0.76, Mo⁶⁺ = 0.73, W⁶⁺ = 0.74 Å; Shannon, 1976) and by the electron configuration of Pt⁴⁺ (5 d⁶), which ??prefers?? octahedral six coordination. These results led us to attempt to synthesize Pt^IV-containing heteropolyoxometalates with the Keggin structure. As a first result of this research project, we have obtained doubly Pt^IV-substituted silicotungstate, (I), the crystal structure of which is reported here.

The systematic extinctions and the diffraction symmetry yielded three possible space groups, viz. I4, I4 and I4/m, among which a reasonable structure model could only be established with the space group I4. The α-Keggin [SiM₁₂O₄₀]^n- (M = W, Pt) anion is located on the 4 site of the crystal, with the result that one-quarter of the anion is crystallographically independent. Elemental analysis (EDXRF) and the requirement of the neutrality of the whole crystal indicated that there are two Pt atoms in the anion. Among the three independent heavy-atom sites, none showed preferred occupation of the Pt atoms. In addition, none of these three sites showed any feature indicating the deviation between the W and Pt positions. Therefore, each heavy-atom site was refined so that the W and Pt atoms share the same coordinates and anisotropic displacement parameters and have fixed occupancy fractions of 5/6 and 1/6, respectively.

The crystal structures of silicododecatungstates with the α- and β- Keggin structures (Keggin, 1934; Tézé & Hervé, 1977) were reported by Kobayashi & Sasaki (1975) and Matsumoto et al. (1975). The substitution of secondary heteroatoms for two of the 12 W atoms has been reported for [γ-SiW₁₀Mn^III₂O₄₀H₆]⁴⁻ (Zhang et al., 1996) and [{β-SiNi₂W₁₀O₃₆(OH)₂(H₂O)}₂]¹²⁻ (Kortz et al., 1999). However, complete studies have not been conducted to date on the crystal structures of the α-Keggin silicotungstates containing two secondary heteroatoms with the formula [α-SiM₂ⁿ⁺W₁₀O₄₀]^{(16 − 2n)-} (M = transition elements).

Fig. 1 shows a perspective view of the anion. The O atoms in the polyanion are classified as either Ot, Oc, Oe or Od. Ot represents terminal O atoms, Oc represents bridging O atoms at corner-sharing linkages, and Oe represents O atoms at edge-sharing linkages. Od represent O atoms coordinating to one Si and three W (Pt) atoms. The structure has an almost Td symmetry, and the {W₁₀Pt₂} framework is very close to a regular ??cubic?? octahedron. When the W(Pt)O₆ octahedra share edges, the W(Pt)—W(Pt) distances vary between 3.3565 (4) and 3.3704 (4) Å while, when sharing corners, they increase to 3.7033 (4)–3.7100 (4) Å. The W(Pt)—O distances are in the ranges 1.721 (5)–1.725 (5) (Ot), 1.910 (5)–1.932 (5) (Oc), 2.339 (4)–2.348 (4) (Od) and 1.934 (5)–1.956 (5) Å (Oe). The central [SiO₄] group is a tetrahedron whose Si—Od distance is 1.646 (4) Å and whose Od—Si—Od angles are 109.2 (3) and 109.6 (2) °. The bond distances and angles in the [α-SiPt₂W₁₀O₄₀]⁸⁻ anion clearly show the character of a typical α-Keggin structure (Table 1).

Fig. 2 shows the unit-cell packing and hydrogen bonding. There are two crystallographically independent guanidinium ions (CH₆N₃⁺) and two water molecules in an asymmetric unit. The structural character of the guanidinium ions agrees well with those in CH₆N₃Cl (Haas et al., 1965) and CH₆N₃(NO₃) (Katrusiak, 1994). The connecting links between the anions are strong hydrogen bonds effected by the guanidinium ions, and the N atoms of the guanidinium ions do not form hydrogen bonds with water molecules. A list of all probable hydrogen-bond distances within 3.1 Å is given in Table 2. The interactions of interwater molecules are not shown. Ow2 forms a weak hydrogen bond with the Oe5 atom of the anion. The TGA trace of (I) dwindled very slowly from room temperature to 515 K, without any sudden change, suggesting that the crystalline water molecules of (I) disintegrate gradually between room temperature and 515 K. These crystalline water molecules seem to behave as zeolitic water.

S2. Experimental

The pH of a mixture of aqueous solutions of K₂Pt(OH)₆ (0.2 g per 20 ml; Lee et al., 1983) and K₈[α-SiW₁₁O₃₉].13H₂O (2.8 g per 30 ml; Contant, 1990) was adjusted to 11.5 by the addition of KOH (3 M), followed by a readjustment to 7.0 by the addition of HNO₃ (3 M). The mixture was then concentrated to about 30 ml on a water bath. Compound (I) was obtained in the form of a pale yellow powder by adding an aqueous solution (30 ml) containing CH₅N₃·HCl (0.3 g) to the reaction mixture. Yellow truncated-tetrahedral crystals of (I) were obtained by recrystallizing a powdered crude sample from the boiling aqueous solution.

Elemental analysis of W and Pt was carried out by regression analysis of EDXRF (Jordan Vally, Spectrometer EX310), using standard samples with Pt:W ratios equal to 1:6, 1:5, and 1:4. The molar ratio of Pt:W in (I) was estimated to be 1:5.3. Standard samples Pt:W equal to 1:4 and 1:5 were prepared by mixing WO₃ and K₂PtCl₆, and the sample with Pt:W eqaul to 1:6 was Na₅[H₃PtW₆O₂₄].22H₂O (Lee et al., 1983). Elemental analysis; calculated: C 2.75, H 1.72, N 9.64%; found: C 2.95, H 1.94, N 9.86%. Thermogravimetric analysis for H₂O; calculated: 3.10%; found: 2.23%. The FT—IR (Perkin Elmer, Spectrum 2000) absorption peaks in the range 500–1000 cm⁻¹ show a pattern typical of the α-Keggin silicotungstates. [KBr disk; 994.24(s), 937.72(s), 871.59(s), 794.26(s), 727.34(s), 520.64(s).]

S3. Refinement

The checkCIF program suggested a higher symmetry of I4/m for this structure, because every atom except Od10 is either located close to the new mirror plane or related to a potential symmetry equivalent. However, a refinement in which all atoms were constrained to conform to the additional symmetry operations was very unstable, leading to a sudden increase of R₁ to 0.1915, with maximum and minimum difference electron densities of 9.35 and −41.71 e Å⁻³, respectively. Therefore, the deviation from the higher symmetry is significant. The new space group, I4/m, could also be adopted by interpreting the structure as a 1:1 disorder comprising 50% of the current chiral structure and 50% of its enantiomorph (although checkCIF did not suggest this interpretation), which is equivalent to treating the structure as a 1:1 racemic twin of the current chiral structure. Refinement of the fractional contributions of the potential twin components converged to 92 (5)% for the current enantiomorph and 8% for the inverted structure, indicating that the racemic twin model with approximately equal amount of the two enantiomer pairs (which approximates to the disordered centric structure with I4/m) should be excluded. Thus the structure was concluded to be chiral with the space group I4.

All H atoms, except water H atoms, were inserted at calculated positions, with N—H distances of 0.86 Å and H—N—H angles of 120°, and treated by the riding model with constrained isotropic displacement parameters [U_iso = 1.2U_eq(N)]. The highest peak in the difference map is 3.21 Å from Ow1, and the largest hole is 0.90 Å from Ow1. Solvent-accessible voids of 96 ų, which are equivalent to a space that about two water molecules could occupy, seem to be empty. Only two independent water molecules were confirmed in a separate low-temperature measurement.

Computing details

Data collection: DIP Xpress (MAC Science, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 1998).

Figures

	Fig. 1. The structure of the [α-SiPt2W10O40]^8− anion. Displacement ellipsoids are shown at the 50% probability level. [Symmetry codes: (i) y, 1 − x, 1 − z; (ii) 1 − x, 1 − y, z; (iii) 1 − y, x, 1 − z.]
	Fig. 2. The crystal packing of (I), with the [α-SiPt2W10O40]^8− anions shown as a polyhedral model. Possible hydrogen bonds are indicated by broken lines.

Octaguanidinium α-silicodiplatinodecatungstate hexahydrate

Crystal data

(CH6N3)8[O40Pt2SiW10]·6H2O	Dx = 3.464 Mg m^−3
Mr = 3485.57	Synchrotron radiation, λ = 0.3282 Å
Tetragonal, I4	Cell parameters from 12596 reflections
Hall symbol: I-4	θ = 2.0–15.8°
a = 13.276 (1) Å	µ = 2.86 mm^−1
c = 18.959 (1) Å	T = 293 K
V = 3341.6 (4) Å^3	Truncated-tetrahedron, yellow
Z = 2	0.15 × 0.15 × 0.15 mm
F(000) = 3108

Data collection

MAC Science DIP LABO diffractometer	7980 independent reflections
Radiation source: fine-focus sealed tube	7961 reflections with I > 2σ(I)
Si(111) monochromator	Rint = 0.032
Detector resolution: 10 pixels mm^-1	θmax = 15.8°, θmin = 2.0°
oscillation method scans	h = −22→22
Absorption correction: multi-scan (PLATON MULABS; Spek, 2003)	k = −22→22
Tmin = 0.522, Tmax = 0.555	l = −31→31
42373 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.029	H-atom parameters constrained
wR(F^2) = 0.068	w = 1/[σ^2(Fo^2) + 65.1125P] where P = (Fo^2 + 2Fc^2)/3
S = 1.26	(Δ/σ)max = 0.001
7980 reflections	Δρmax = 2.09 e Å^−3
207 parameters	Δρmin = −2.55 e Å^−3
0 restraints	Absolute structure: (Flack, 1983), 3878 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.08 (5)

Special details

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)
W1	0.344386 (19)	0.393810 (19)	0.368398 (16)	0.01991 (5)	0.83
Pt1	0.344386 (19)	0.393810 (19)	0.368398 (16)	0.01991 (5)	0.17
W2	0.235962 (16)	0.53609 (2)	0.493510 (13)	0.01951 (4)	0.83
Pt2	0.235962 (16)	0.53609 (2)	0.493510 (13)	0.01951 (4)	0.17
W3	0.379342 (19)	0.644708 (18)	0.368059 (15)	0.01938 (5)	0.83
Pt3	0.379342 (19)	0.644708 (18)	0.368059 (15)	0.01938 (5)	0.17
Si	0.5000	0.5000	0.5000	0.0159 (5)
Ot1	0.2879 (4)	0.3198 (4)	0.3053 (3)	0.0253 (10)
Ot2	0.1101 (3)	0.5536 (4)	0.5119 (3)	0.0269 (10)
Ot3	0.3467 (4)	0.7334 (4)	0.3056 (3)	0.0266 (10)
Oe4	0.2242 (4)	0.4345 (4)	0.4209 (3)	0.0221 (8)
Oe5	0.2528 (4)	0.6362 (4)	0.4194 (2)	0.0215 (8)
Oe6	0.3409 (4)	0.5223 (4)	0.3188 (2)	0.0217 (8)
Oc7	0.5156 (4)	0.6181 (4)	0.3418 (3)	0.0212 (8)
Oc8	0.2960 (4)	0.6277 (4)	0.5595 (3)	0.0212 (8)
Oc9	0.4309 (4)	0.7311 (4)	0.4408 (3)	0.0207 (8)
Od10	0.3999 (3)	0.5142 (3)	0.4497 (2)	0.0151 (7)
C1	0.1961 (12)	0.5002 (7)	0.1541 (6)	0.059 (4)
N1	0.1385 (11)	0.5230 (7)	0.0980 (6)	0.068 (4)
H1A	0.1200	0.5842	0.0910	0.081*
H1B	0.1203	0.4764	0.0693	0.081*
N2	0.2231 (12)	0.4051 (7)	0.1638 (7)	0.075 (4)
H2A	0.2596	0.3890	0.1995	0.090*
H2B	0.2040	0.3596	0.1344	0.090*
N3	0.2222 (14)	0.5701 (8)	0.1959 (7)	0.095 (6)
H3A	0.2587	0.5566	0.2321	0.114*
H3B	0.2033	0.6310	0.1880	0.114*
C2	0.3198 (13)	1.0004 (10)	0.3410 (9)	0.065 (4)
N4	0.2758 (14)	0.9461 (8)	0.2898 (7)	0.089 (5)
H4A	0.2429	0.9759	0.2568	0.107*
H4B	0.2805	0.8814	0.2901	0.107*
N5	0.3745 (12)	0.9507 (9)	0.3893 (6)	0.076 (4)
H5A	0.4064	0.9835	0.4214	0.091*
H5B	0.3777	0.8860	0.3881	0.091*
N6	0.3125 (15)	1.0986 (9)	0.3405 (8)	0.100 (7)
H6A	0.3435	1.1337	0.3719	0.120*
H6B	0.2768	1.1281	0.3088	0.120*
Ow1	0.5000	0.5000	0.1949 (8)	0.126 (8)
Ow2	0.2007 (16)	0.8262 (10)	0.5015 (17)	0.178 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
W1	0.02067 (10)	0.02074 (10)	0.01833 (10)	−0.00228 (7)	−0.00428 (9)	−0.00320 (9)
Pt1	0.02067 (10)	0.02074 (10)	0.01833 (10)	−0.00228 (7)	−0.00428 (9)	−0.00320 (9)
W2	0.01312 (9)	0.02381 (11)	0.02159 (9)	0.00160 (8)	0.00118 (8)	0.00019 (9)
Pt2	0.01312 (9)	0.02381 (11)	0.02159 (9)	0.00160 (8)	0.00118 (8)	0.00019 (9)
W3	0.02164 (10)	0.01865 (9)	0.01785 (10)	0.00119 (7)	−0.00220 (9)	0.00483 (8)
Pt3	0.02164 (10)	0.01865 (9)	0.01785 (10)	0.00119 (7)	−0.00220 (9)	0.00483 (8)
Si	0.0162 (7)	0.0162 (7)	0.0152 (11)	0.000	0.000	0.000
Ot1	0.025 (2)	0.024 (2)	0.027 (2)	−0.0004 (18)	−0.0076 (18)	−0.0086 (18)
Ot2	0.0139 (17)	0.038 (3)	0.028 (3)	0.0043 (17)	0.0027 (16)	0.002 (2)
Ot3	0.028 (2)	0.025 (2)	0.027 (2)	0.0033 (18)	−0.0083 (19)	0.0071 (18)
Oe4	0.021 (2)	0.024 (2)	0.022 (2)	−0.0039 (16)	−0.0021 (16)	−0.0025 (16)
Oe5	0.0201 (19)	0.024 (2)	0.0203 (19)	0.0019 (16)	0.0016 (15)	0.0039 (16)
Oe6	0.025 (2)	0.022 (2)	0.0188 (19)	−0.0011 (16)	−0.0035 (16)	−0.0017 (15)
Oc7	0.0184 (19)	0.0210 (19)	0.024 (2)	−0.0006 (15)	−0.0005 (16)	−0.0034 (16)
Oc8	0.023 (2)	0.0198 (19)	0.0207 (19)	−0.0020 (16)	−0.0015 (16)	−0.0015 (15)
Oc9	0.0195 (19)	0.022 (2)	0.0205 (19)	−0.0008 (16)	−0.0023 (15)	−0.0015 (15)
Od10	0.0135 (15)	0.0174 (17)	0.0145 (16)	0.0004 (13)	−0.0045 (12)	−0.0007 (13)
C1	0.106 (10)	0.019 (3)	0.053 (6)	0.007 (4)	−0.052 (7)	−0.003 (3)
N1	0.118 (10)	0.028 (4)	0.057 (6)	0.017 (5)	−0.059 (6)	−0.010 (4)
N2	0.134 (12)	0.025 (4)	0.066 (7)	0.019 (5)	−0.047 (8)	−0.003 (4)
N3	0.160 (15)	0.035 (5)	0.091 (9)	0.027 (7)	−0.097 (10)	−0.025 (5)
C2	0.080 (10)	0.039 (6)	0.076 (9)	0.004 (6)	−0.027 (8)	−0.013 (6)
N4	0.153 (13)	0.037 (5)	0.078 (7)	0.028 (6)	−0.089 (9)	−0.012 (5)
N5	0.126 (12)	0.053 (6)	0.050 (6)	0.000 (7)	−0.047 (7)	−0.003 (5)
N6	0.186 (18)	0.031 (5)	0.084 (9)	0.012 (7)	−0.081 (10)	−0.012 (5)
Ow1	0.095 (17)	0.22 (3)	0.062 (9)	−0.03 (2)	0.000	0.000
Ow2	0.25 (2)	0.078 (9)	0.210 (19)	0.070 (11)	−0.06 (2)	−0.064 (14)

Geometric parameters (Å, º)

W1—W2	3.3565 (4)	C1—N3	1.268 (13)
W1—W3	3.3631 (4)	C1—N2	1.324 (13)
W2—W3	3.3704 (4)	C1—N1	1.344 (12)
W1—W2^i	3.7100 (4)	C2—N6	1.308 (17)
W1—W3^ii	3.7033 (4)	C2—N5	1.342 (18)
W2—W3^i	3.7051 (4)	C2—N4	1.342 (17)
W1—Ot1	1.721 (5)	Ow1—Oe6^ii	3.174 (13)
W1—Oc8^i	1.921 (5)	Ow1—Oc7	3.204 (14)
W1—Oc7^ii	1.932 (5)	Ow1—Oe6	3.174 (13)
W1—Oe6	1.948 (5)	Ow1—Oe6	3.174 (13)
W1—Oe4	1.956 (5)	Ow2—Oe5	3.043 (17)
W1—Od10	2.339 (4)	Ow2—Oc8	3.123 (19)
W2—Ot2	1.722 (4)	N5—Ot2^iii	3.132 (13)
W2—Oc8	1.919 (5)	N1—H1A	0.8600
W2—Oc9^i	1.922 (5)	N1—H1B	0.8600
W2—Oe4	1.934 (5)	N2—H2A	0.8600
W2—Oe5	1.948 (5)	N2—H2B	0.8600
W2—Od10	2.348 (4)	N3—H3A	0.8600
W3—Ot3	1.725 (5)	N3—H3B	0.8600
W3—Oc7	1.910 (5)	N4—H4A	0.8600
W3—Oc9	1.920 (5)	N4—H4B	0.8600
W3—Oe6	1.943 (5)	N5—H5A	0.8600
W3—Oe5	1.945 (5)	N5—H5B	0.8600
W3—Od10	2.339 (4)	N6—H6A	0.8600
Si—Od10	1.646 (4)	N6—H6B	0.8600
W3^ii—W1—W2^i	59.974 (7)	Oc9—W3—Od10	85.73 (18)
W2—W1—W3	60.209 (8)	Oe6—W3—Od10	74.26 (17)
W1—W2—W3	59.992 (8)	Oe5—W3—Od10	74.18 (17)
W2—W1—W2^i	90.149 (9)	W2—Oe4—W1	119.3 (2)
W1—W2—W3^i	90.066 (9)	W3—Oe5—W2	120.0 (2)
Od10^i—Si—Od10	109.63 (15)	W3—Oe5—Ow2	113.8 (5)
Od10—Si—Od10^ii	109.2 (3)	W2—Oe5—Ow2	99.8 (6)
W1—W3—W2	59.799 (8)	W3—Oe6—W1	119.6 (2)
Ot1—W1—Oc8^i	101.1 (2)	W3—Oe6—Ow1	105.0 (2)
Ot1—W1—Oc7^ii	101.0 (2)	W1—Oe6—Ow1	105.1 (2)
Oc8^i—W1—Oc7^ii	86.8 (2)	W3—Oc7—W1^ii	149.2 (3)
Ot1—W1—Oe6	98.9 (2)	W3—Oc7—Ow1	104.81 (18)
Oc8^i—W1—Oe6	160.0 (2)	W1^ii—Oc7—Ow1	104.42 (18)
Oc7^ii—W1—Oe6	88.2 (2)	W2—Oc8—W1^iii	150.1 (3)
Ot1—W1—Oe4	99.0 (2)	W2—Oc8—Ow2	97.9 (4)
Oc8^i—W1—Oe4	89.0 (2)	W1^iii—Oc8—Ow2	111.2 (4)
Oc7^ii—W1—Oe4	160.0 (2)	W3—Oc9—W2^iii	149.4 (3)
Oe6—W1—Oe4	89.1 (2)	W1—Od10—W3	91.92 (14)
Ot1—W1—Od10	170.3 (2)	W1—Od10—W2	91.46 (14)
Oc8^i—W1—Od10	86.13 (18)	W3—Od10—W2	91.94 (14)
Oc7^ii—W1—Od10	85.67 (18)	N3—C1—N2	122.5 (10)
Oe6—W1—Od10	74.18 (17)	N3—C1—N1	118.9 (9)
Oe4—W1—Od10	74.55 (17)	N2—C1—N1	118.6 (9)
W3—W1—W2^i	120.118 (10)	N6—C2—N5	122.3 (13)
Ot2—W2—Oc8	100.7 (2)	N6—C2—N4	119.9 (13)
Ot2—W2—Oc9^i	100.8 (2)	N5—C2—N4	117.7 (11)
Oc8—W2—Oc9^i	86.8 (2)	Oe6^ii—Ow1—Oe6	84.5 (4)
Ot2—W2—Oe4	99.2 (2)	Oe6^ii—Ow1—Oc7	50.1 (2)
Oc8—W2—Oe4	160.1 (2)	Oe6—Ow1—Oc7	49.7 (2)
Oc9^i—W2—Oe4	88.4 (2)	Oe6^ii—Ow1—Oc7^ii	49.7 (2)
Ot2—W2—Oe5	99.5 (2)	Oe6—Ow1—Oc7^ii	50.1 (2)
Oc8—W2—Oe5	89.5 (2)	Oc7—Ow1—Oc7^ii	59.2 (3)
Oc9^i—W2—Oe5	159.7 (2)	Oe5—Ow2—Oc8	52.4 (2)
Oe4—W2—Oe5	88.4 (2)	C1—N1—H1A	120.0
Ot2—W2—Od10	171.0 (2)	C1—N1—H1B	120.0
Oc8—W2—Od10	85.67 (18)	H1A—N1—H1B	120.0
Oc9^i—W2—Od10	85.87 (18)	C1—N2—H2A	120.0
Oe4—W2—Od10	74.71 (17)	C1—N2—H2B	120.0
Oe5—W2—Od10	73.92 (17)	H2A—N2—H2B	120.0
W3—W2—W3^i	119.912 (10)	C1—N3—H3A	120.0
Ot3—W3—Oc7	100.7 (2)	C1—N3—H3B	120.0
Ot3—W3—Oc9	100.1 (2)	H3A—N3—H3B	120.0
Oc7—W3—Oc9	87.7 (2)	C2—N4—H4A	120.0
Ot3—W3—Oe6	100.1 (2)	C2—N4—H4B	120.0
Oc7—W3—Oe6	88.2 (2)	H4A—N4—H4B	120.0
Oc9—W3—Oe6	159.8 (2)	C2—N5—H5A	120.0
Ot3—W3—Oe5	99.5 (2)	C2—N5—H5B	120.0
Oc7—W3—Oe5	159.8 (2)	H5A—N5—H5B	120.0
Oc9—W3—Oe5	89.0 (2)	C2—N6—H6A	120.0
Oe6—W3—Oe5	88.0 (2)	C2—N6—H6B	120.0
Ot3—W3—Od10	171.5 (2)	H6A—N6—H6B	120.0
Oc7—W3—Od10	85.67 (18)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···Ot2^iv	0.86	2.11	2.957 (10)	166
N1—H1A···Oe4^v	0.86	2.01	2.864 (10)	175
N2—H2A···Ot1	0.86	2.24	3.036 (12)	155
N2—H2B···Oe5^iv	0.86	2.02	2.865 (12)	168
N3—H3B···Ot1^v	0.86	2.11	2.945 (11)	164
N3—H3A···Oe6	0.86	2.02	2.884 (11)	178
N4—H4B···Ot1^v	0.86	2.57	3.045 (13)	116
N4—H4B···Ot3	0.86	2.17	2.991 (12)	159
N5—H5A···Ot2^vi	0.86	2.17	2.984 (12)	158
N6—H6B···Ot1^vii	0.86	2.55	3.029 (13)	116
N6—H6B···Ot3^viii	0.86	2.27	3.050 (14)	151

Symmetry codes: (iv) y−1/2, −x+1/2, −z+1/2; (v) −y+1/2, x+1/2, −z+1/2; (vi) −y+1, x+1, −z+1; (vii) x, y+1, z; (viii) y−1/2, −x+3/2, −z+1/2.