Tetra­kis(2-methyl­benzimidazolium) β-octa­molybdate(VI)

Hao, L.; Zhang, X.; Chen, J.

doi:10.1107/S1600536810012304

metal-organic compounds

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ISSN: 2056-9890

Volume 66| Part 5| May 2010| Page m505

https://doi.org/10.1107/S1600536810012304

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Tetrakis(2-methylbenzimidazolium) β-octamolybdate(VI)

Lujiang Hao,^a ^* Xiaofei Zhang ^a and Jiangkui Chen ^a

^aCollege of Food and Biological Engineering, Shandong Institute of Light Industry, Jinan 250353, People's Republic of China
^*Correspondence e-mail: lujianghao001@yahoo.com.cn

(Received 20 March 2010; accepted 1 April 2010; online 10 April 2010)

The asymmetric unit of the title compound, (C₈H₉N₂)₄[Mo₈O₂₆], consists of two 2-methylbenzimidazolium cations and one-half of a β-Mo₈O₂₆⁴⁻ anion, which is completed by crystallographic inversion symmetry. An extensive net of N—H⋯O hydrogen bonds between the cations and anions contribute to the crystal packing.

Related literature

For general background to polyoxometalates, see: Pope & Müller (1991 ). For polyoxometalates modified with amines, see: Zhang, Dou et al. (2009 ); Zhang, Wei et al. (2009 ). For the structures of other polyoxidomolybdates with the β-[Mo₈O₂₆]⁴⁻ anion, see, for example: Chen et al. (2004 ); Isobe et al. (1978 ); Li et al. (2004 ); Lu et al. (2000 ).

Experimental

Crystal data

(C₈H₉N₂)₄[Mo₈O₂₆]
M_r = 1716.21
Monoclinic, P 2₁ /n
a = 10.4831 (12) Å
b = 17.803 (2) Å
c = 13.794 (2) Å
β = 112.305 (5)°
V = 2381.6 (5) Å³
Z = 2
Mo Kα radiation
μ = 2.13 mm⁻¹
T = 296 K
0.12 × 0.10 × 0.08 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ) T_min = 0.784, T_max = 0.848
11151 measured reflections
4167 independent reflections
3566 reflections with I > 2σ(I)
R_int = 0.043

Refinement

R[F² > 2σ(F²)] = 0.022
wR(F²) = 0.063
S = 1.00
4167 reflections
336 parameters
H-atom parameters constrained
Δρ_max = 0.53 e Å⁻³
Δρ_min = −0.59 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O5ⁱ	0.86	1.95	2.811 (4)	176
N2—H2⋯O13ⁱⁱ	0.86	2.06	2.857 (4)	155
N3—H3⋯O1ⁱ	0.86	1.99	2.752 (4)	147
N4—H4⋯O4ⁱⁱⁱ	0.86	2.30	3.089 (4)	154
N4—H4⋯O2ⁱⁱⁱ	0.86	2.41	3.060 (5)	133
Symmetry codes: (i) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) x, y+1, z-1; (iii) -x+1, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2004 ); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810012304/wm2318sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810012304/wm2318Isup2.hkl

checkCIF report

Comment top

The design and synthesis of polyoxometalates has attracted continuous research interest not only because of their appealing structural and topological novelties, but also due to their interesting optical, electronic, magnetic, and catalytic properties, as well as their potential medical applications (Pope & Müller, 1991). In our research group, organic amines, such as 3-(2-pyridyl)pyrazole and pyrazine, are used to effectively modify polyoxomolybdates under hydrothermal condictions (Zhang, Dou et al., 2009; Zhang, Wei et al., 2009). Here, we describe the synthesis and structural characterization of the title compound.

As shown in Figure 1, the title compound consists of two 3-H-2-methylbenzimidazolium cations and one-half of a Mo₈O₂₆^4- anion. The octamolybdate polyanion shows a β-configuration with a center of symmetry. The bond lengths and angles within the anion are very similar to previously reported polyoxidomolybdates with the β-Mo₈O₂₆^4- structure (Chen et al., 2004; Isobe et al., 1978; Li et al., 2004; Lu et al., 2000). The anion can formally be bisected into two [(µ5-O)(Mo₄O₁₂)]^2- subunits by breaking the Mo—Oⁱ bonds (-x, -y, -z+2). In this subunit, four Mo atoms sit approximately in a plane. There are four types of Mo—O bonds within the anion: terminal Mo—O bonds and bridging µ2-O—Mo, µ3-O—Mo, and µ5-O—Mo bonds. The corresponding bond lengths vary from the shortest with 1.686 (2) Å for one of the terminal Mo—O bonds, to the longest with 2.519 (3) Å for one of the bonds to the unusual µ5-O atom (O8) that sits in the 4 Mo plane near the center of each Mo—O moiety.

N—H···O hydrogen bonding between the cations and anions leads to a consolidation of the structure (Fig. 2; Table 1).

Related literature top

For general background to polyoxometalates, see: Pope & Müller (1991). For polyoxometalates modified with amines, see: Zhang, Dou et al. (2009); Zhang, Wei et al. (2009). For the structures of other polyoxidomolybdates with the β-[Mo₈O₂₆]^4- anion, see, for example: Chen et al. (2004); Isobe et al. (1978); Li et al, (2004); Lu et al. (2000).

Experimental top

A mixture of 2-methylbenzimidazole (0.5 mmoL 0.07 g), sodium molybdate (0.4 mmoL, 0.10 g), and iron(III) chloride hexahydrate (0.25 mmol, 0.07 g) in 10 ml distilled water was sealed in a 25 ml Teflon-lined stainless steel autoclave and was kept at 433 K for three days. Colorless crystals suitable for the X-ray experiment were obtained. Anal. / calc. for C₃₂H₃₆Mo₈N₈O₂₆: C, 22.37; H, 2.10; N, 6.53. Found: C, 22.10; H, 1.98; N, 6.27 %.

Structure description top

N—H···O hydrogen bonding between the cations and anions leads to a consolidation of the structure (Fig. 2; Table 1).

For general background to polyoxometalates, see: Pope & Müller (1991). For polyoxometalates modified with amines, see: Zhang, Dou et al. (2009); Zhang, Wei et al. (2009). For the structures of other polyoxidomolybdates with the β-[Mo₈O₂₆]^4- anion, see, for example: Chen et al. (2004); Isobe et al. (1978); Li et al, (2004); Lu et al. (2000).

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The building blocks of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level; H atoms are given as spheres of arbitrary radius.
	Fig. 2. The crystal packing of the title compound, displayed with N—H···O hydrogen bonds as dashed lines.

Tetrakis(2-methylbenzimidazolium) β-octamolybdate(VI) top

Crystal data top

(C₈H₉N₂)₄[Mo₈O₂₆]	F(000) = 1656
M_r = 1716.21	D_x = 2.393 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 8117 reflections
a = 10.4831 (12) Å	θ = 2.4–30.0°
b = 17.803 (2) Å	µ = 2.13 mm⁻¹
c = 13.794 (2) Å	T = 296 K
β = 112.305 (5)°	Block, colorless
V = 2381.6 (5) Å³	0.12 × 0.10 × 0.08 mm
Z = 2

Data collection top

Bruker APEXII CCD diffractometer	4167 independent reflections
Radiation source: fine-focus sealed tube	3566 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.043
φ– and ω–scans	θ_max = 25.0°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −12→12
T_min = 0.784, T_max = 0.848	k = −21→16
11151 measured reflections	l = −16→16

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.022	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.063	H-atom parameters constrained
S = 1.00	w = 1/[σ²(F_o²) + (0.030P)² + 3.2003P] where P = (F_o² + 2F_c²)/3
4167 reflections	(Δ/σ)_max = 0.001
336 parameters	Δρ_max = 0.53 e Å⁻³
0 restraints	Δρ_min = −0.59 e Å⁻³

Crystal data top

(C₈H₉N₂)₄[Mo₈O₂₆]	V = 2381.6 (5) Å³
M_r = 1716.21	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 10.4831 (12) Å	µ = 2.13 mm⁻¹
b = 17.803 (2) Å	T = 296 K
c = 13.794 (2) Å	0.12 × 0.10 × 0.08 mm
β = 112.305 (5)°

Data collection top

Bruker APEXII CCD diffractometer	4167 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2001)	3566 reflections with I > 2σ(I)
T_min = 0.784, T_max = 0.848	R_int = 0.043
11151 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.022	0 restraints
wR(F²) = 0.063	H-atom parameters constrained
S = 1.00	Δρ_max = 0.53 e Å⁻³
4167 reflections	Δρ_min = −0.59 e Å⁻³
336 parameters

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.2704 (6)	0.7102 (3)	0.2134 (4)	0.0630 (14)
H1A	0.3083	0.7395	0.2763	0.094*
H1B	0.2536	0.6599	0.2307	0.094*
H1C	0.1853	0.7323	0.1677	0.094*
C2	0.3686 (5)	0.7086 (2)	0.1602 (3)	0.0467 (11)
C3	0.5050 (5)	0.6647 (2)	0.0825 (3)	0.0432 (11)
C4	0.5084 (5)	0.7430 (2)	0.0804 (3)	0.0450 (11)
C5	0.5869 (6)	0.7808 (3)	0.0347 (3)	0.0582 (14)
H5	0.5910	0.8329	0.0340	0.070*
C6	0.6577 (6)	0.7372 (3)	−0.0094 (4)	0.0628 (15)
H6	0.7106	0.7608	−0.0414	0.075*
C7	0.6544 (6)	0.6583 (3)	−0.0086 (4)	0.0577 (13)
H7	0.7048	0.6310	−0.0394	0.069*
C8	0.5768 (5)	0.6212 (2)	0.0378 (3)	0.0484 (11)
H8	0.5731	0.5690	0.0388	0.058*
C9	0.9368 (6)	0.7591 (3)	0.2339 (4)	0.0662 (15)
H9A	0.9239	0.7804	0.1668	0.099*
H9B	0.9127	0.7068	0.2256	0.099*
H9C	1.0315	0.7644	0.2801	0.099*
C10	0.8481 (6)	0.7986 (3)	0.2785 (3)	0.0553 (13)
C11	0.7365 (5)	0.8896 (3)	0.3277 (3)	0.0504 (12)
C12	0.7073 (5)	0.8199 (3)	0.3619 (3)	0.0535 (13)
C13	0.6212 (6)	0.8145 (3)	0.4162 (4)	0.0681 (16)
H13	0.5999	0.7685	0.4381	0.082*
C14	0.5692 (6)	0.8797 (4)	0.4361 (4)	0.0759 (17)
H14	0.5109	0.8777	0.4728	0.091*
C15	0.5990 (6)	0.9503 (4)	0.4041 (4)	0.0716 (16)
H15	0.5611	0.9936	0.4199	0.086*
C16	0.6846 (6)	0.9552 (3)	0.3490 (4)	0.0592 (13)
H16	0.7061	1.0013	0.3273	0.071*
Mo1	0.04862 (3)	0.096451 (15)	1.00469 (2)	0.02172 (9)
Mo2	−0.15562 (4)	0.030802 (16)	0.78252 (2)	0.02654 (9)
Mo3	0.16768 (3)	−0.051020 (16)	0.89081 (2)	0.02505 (9)
Mo4	0.37656 (4)	0.016654 (17)	1.11342 (3)	0.02963 (10)
N1	0.4180 (4)	0.64678 (18)	0.1335 (3)	0.0448 (9)
H1	0.3986	0.6018	0.1462	0.054*
N2	0.4224 (5)	0.76737 (19)	0.1295 (3)	0.0508 (10)
H2	0.4062	0.8136	0.1388	0.061*
N3	0.7772 (5)	0.7662 (2)	0.3297 (3)	0.0555 (11)
H3	0.7754	0.7188	0.3409	0.067*
N4	0.8238 (4)	0.8718 (2)	0.2755 (3)	0.0544 (11)
H4	0.8574	0.9042	0.2453	0.065*
O1	0.2370 (3)	−0.13795 (14)	0.9258 (2)	0.0361 (6)
O2	0.1516 (3)	−0.03926 (15)	0.7647 (2)	0.0384 (7)
O3	0.3162 (3)	0.01243 (13)	0.96278 (19)	0.0307 (6)
O4	0.0395 (3)	0.06073 (12)	0.86774 (17)	0.0251 (5)
O5	−0.1357 (3)	0.00303 (15)	0.67023 (19)	0.0377 (7)
O6	−0.3086 (3)	−0.02676 (13)	0.77550 (19)	0.0313 (6)
O7	−0.2220 (3)	0.11838 (14)	0.7564 (2)	0.0405 (7)
O8	−0.1309 (3)	0.02939 (12)	0.95578 (17)	0.0242 (5)
O9	−0.0207 (3)	0.18273 (13)	0.97196 (19)	0.0327 (6)
O10	0.0283 (3)	0.07826 (12)	1.13665 (17)	0.0238 (5)
O11	0.2261 (3)	0.11265 (13)	1.05853 (19)	0.0291 (6)
O12	0.5156 (3)	0.07420 (16)	1.1525 (2)	0.0429 (7)
O13	0.4390 (3)	−0.07249 (15)	1.1401 (2)	0.0398 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.079 (4)	0.043 (3)	0.070 (3)	0.022 (3)	0.032 (3)	0.014 (2)
C2	0.056 (3)	0.030 (2)	0.044 (2)	0.008 (2)	0.008 (2)	0.0069 (18)
C3	0.052 (3)	0.028 (2)	0.040 (2)	−0.009 (2)	0.006 (2)	0.0075 (17)
C4	0.054 (3)	0.027 (2)	0.038 (2)	−0.007 (2)	0.001 (2)	0.0049 (17)
C5	0.071 (4)	0.038 (3)	0.050 (3)	−0.023 (3)	0.005 (3)	0.011 (2)
C6	0.070 (4)	0.057 (3)	0.055 (3)	−0.027 (3)	0.017 (3)	0.008 (2)
C7	0.059 (4)	0.057 (3)	0.053 (3)	−0.014 (3)	0.017 (3)	0.000 (2)
C8	0.060 (3)	0.035 (2)	0.048 (2)	−0.006 (2)	0.018 (2)	0.002 (2)
C9	0.078 (5)	0.060 (3)	0.057 (3)	−0.004 (3)	0.022 (3)	0.012 (3)
C10	0.056 (4)	0.055 (3)	0.042 (2)	−0.017 (3)	0.005 (2)	0.019 (2)
C11	0.037 (3)	0.054 (3)	0.049 (2)	−0.013 (2)	0.004 (2)	0.021 (2)
C12	0.045 (3)	0.059 (3)	0.045 (2)	−0.020 (3)	0.005 (2)	0.022 (2)
C13	0.065 (4)	0.071 (4)	0.067 (3)	−0.018 (3)	0.023 (3)	0.025 (3)
C14	0.058 (4)	0.103 (5)	0.073 (4)	−0.003 (4)	0.030 (3)	0.026 (4)
C15	0.057 (4)	0.078 (4)	0.075 (3)	0.007 (3)	0.020 (3)	0.023 (3)
C16	0.045 (3)	0.056 (3)	0.068 (3)	−0.003 (3)	0.012 (3)	0.023 (3)
Mo1	0.0292 (2)	0.01279 (14)	0.02839 (15)	0.00022 (12)	0.01688 (14)	0.00018 (11)
Mo2	0.0334 (2)	0.01937 (16)	0.02819 (16)	0.00220 (13)	0.01317 (15)	0.00172 (12)
Mo3	0.0308 (2)	0.01887 (15)	0.03238 (16)	0.00054 (13)	0.01981 (15)	−0.00203 (12)
Mo4	0.0279 (2)	0.02408 (17)	0.03886 (18)	0.00065 (13)	0.01489 (16)	−0.00324 (13)
N1	0.058 (3)	0.0221 (16)	0.054 (2)	0.0012 (17)	0.022 (2)	0.0097 (15)
N2	0.070 (3)	0.0210 (17)	0.049 (2)	0.0021 (18)	0.009 (2)	0.0086 (15)
N3	0.062 (3)	0.046 (2)	0.050 (2)	−0.019 (2)	0.012 (2)	0.0170 (18)
N4	0.050 (3)	0.049 (2)	0.058 (2)	−0.0124 (19)	0.014 (2)	0.0295 (19)
O1	0.0372 (18)	0.0232 (13)	0.0545 (16)	0.0030 (12)	0.0251 (14)	−0.0021 (12)
O2	0.048 (2)	0.0385 (15)	0.0393 (14)	−0.0047 (13)	0.0280 (14)	−0.0034 (12)
O3	0.0336 (17)	0.0265 (13)	0.0407 (14)	−0.0021 (11)	0.0240 (13)	−0.0025 (11)
O4	0.0326 (16)	0.0182 (11)	0.0307 (12)	−0.0016 (10)	0.0191 (12)	0.0002 (10)
O5	0.050 (2)	0.0327 (14)	0.0330 (13)	0.0010 (13)	0.0192 (13)	0.0012 (11)
O6	0.0319 (17)	0.0275 (13)	0.0342 (13)	−0.0010 (11)	0.0121 (12)	−0.0037 (11)
O7	0.044 (2)	0.0242 (14)	0.0467 (15)	0.0063 (13)	0.0105 (14)	0.0023 (12)
O8	0.0260 (15)	0.0180 (11)	0.0331 (12)	0.0023 (10)	0.0161 (11)	0.0010 (10)
O9	0.0456 (19)	0.0192 (12)	0.0389 (13)	0.0050 (12)	0.0223 (13)	0.0019 (10)
O10	0.0301 (16)	0.0175 (11)	0.0277 (11)	−0.0007 (10)	0.0154 (11)	−0.0018 (9)
O11	0.0333 (17)	0.0208 (12)	0.0385 (13)	−0.0022 (11)	0.0197 (12)	−0.0015 (10)
O12	0.0305 (18)	0.0396 (16)	0.0591 (17)	−0.0047 (13)	0.0176 (14)	−0.0087 (14)
O13	0.0398 (19)	0.0302 (14)	0.0492 (15)	0.0072 (13)	0.0167 (14)	−0.0008 (13)

Geometric parameters (Å, º) top

C1—C2	1.473 (7)	Mo1—O9	1.686 (2)
C1—H1A	0.9600	Mo1—O11	1.746 (3)
C1—H1B	0.9600	Mo1—O10	1.939 (2)
C1—H1C	0.9600	Mo1—O4	1.961 (2)
C2—N2	1.332 (6)	Mo1—O8	2.112 (2)
C2—N1	1.326 (5)	Mo1—O8ⁱ	2.388 (2)
C3—N1	1.384 (6)	Mo1—Mo3ⁱ	3.2178 (5)
C3—C8	1.378 (6)	Mo1—Mo2	3.2189 (6)
C3—C4	1.395 (5)	Mo2—O7	1.689 (3)
C4—C5	1.386 (7)	Mo2—O5	1.712 (2)
C4—N2	1.386 (6)	Mo2—O6	1.874 (3)
C5—C6	1.366 (8)	Mo2—O4	2.007 (3)
C5—H5	0.9300	Mo2—O8	2.304 (2)
C6—C7	1.405 (7)	Mo2—O10ⁱ	2.380 (2)
C6—H6	0.9300	Mo3—O2	1.696 (2)
C7—C8	1.379 (6)	Mo3—O1	1.700 (3)
C7—H7	0.9300	Mo3—O3	1.874 (3)
C8—H8	0.9300	Mo3—O10ⁱ	2.002 (2)
C9—C10	1.474 (8)	Mo3—O8ⁱ	2.322 (2)
C9—H9A	0.9600	Mo3—O4	2.354 (2)
C9—H9B	0.9600	Mo3—Mo1ⁱ	3.2178 (5)
C9—H9C	0.9600	Mo4—O12	1.694 (3)
C10—N4	1.326 (6)	Mo4—O13	1.703 (3)
C10—N3	1.335 (6)	Mo4—O6ⁱ	1.928 (2)
C11—C16	1.366 (7)	Mo4—O3	1.930 (2)
C11—N4	1.399 (6)	Mo4—O11	2.253 (3)
C11—C12	1.402 (6)	Mo4—O8ⁱ	2.519 (3)
C12—N3	1.377 (7)	N1—H1	0.8600
C12—C13	1.377 (7)	N2—H2	0.8600
C13—C14	1.353 (8)	N3—H3	0.8600
C13—H13	0.9300	N4—H4	0.8600
C14—C15	1.407 (8)	O6—Mo4ⁱ	1.928 (2)
C14—H14	0.9300	O8—Mo3ⁱ	2.322 (2)
C15—C16	1.381 (8)	O8—Mo1ⁱ	2.388 (2)
C15—H15	0.9300	O10—Mo3ⁱ	2.002 (2)
C16—H16	0.9300	O10—Mo2ⁱ	2.380 (2)

C2—C1—H1A	109.5	Mo3ⁱ—Mo1—Mo2	90.460 (15)
C2—C1—H1B	109.5	O7—Mo2—O5	104.76 (13)
H1A—C1—H1B	109.5	O7—Mo2—O6	102.64 (13)
C2—C1—H1C	109.5	O5—Mo2—O6	101.01 (12)
H1A—C1—H1C	109.5	O7—Mo2—O4	97.22 (12)
H1B—C1—H1C	109.5	O5—Mo2—O4	99.18 (12)
N2—C2—N1	107.8 (4)	O6—Mo2—O4	146.89 (10)
N2—C2—C1	127.1 (4)	O7—Mo2—O8	96.12 (11)
N1—C2—C1	125.1 (4)	O5—Mo2—O8	158.55 (11)
N1—C3—C8	132.5 (4)	O6—Mo2—O8	78.74 (9)
N1—C3—C4	105.5 (4)	O4—Mo2—O8	72.97 (8)
C8—C3—C4	122.0 (4)	O7—Mo2—O10ⁱ	164.81 (11)
C5—C4—N2	132.7 (4)	O5—Mo2—O10ⁱ	87.08 (10)
C5—C4—C3	121.2 (5)	O6—Mo2—O10ⁱ	83.97 (10)
N2—C4—C3	106.1 (4)	O4—Mo2—O10ⁱ	71.11 (9)
C6—C5—C4	116.4 (4)	O8—Mo2—O10ⁱ	71.52 (8)
C6—C5—H5	121.8	O7—Mo2—Mo1	86.53 (10)
C4—C5—H5	121.8	O5—Mo2—Mo1	134.48 (10)
C5—C6—C7	123.0 (5)	O6—Mo2—Mo1	119.64 (7)
C5—C6—H6	118.5	O4—Mo2—Mo1	35.30 (6)
C7—C6—H6	118.5	O8—Mo2—Mo1	40.91 (6)
C8—C7—C6	120.2 (5)	O10ⁱ—Mo2—Mo1	78.35 (6)
C8—C7—H7	119.9	O2—Mo3—O1	105.60 (13)
C6—C7—H7	119.9	O2—Mo3—O3	102.02 (12)
C3—C8—C7	117.2 (4)	O1—Mo3—O3	102.64 (13)
C3—C8—H8	121.4	O2—Mo3—O10ⁱ	98.07 (12)
C7—C8—H8	121.4	O1—Mo3—O10ⁱ	97.49 (12)
C10—C9—H9A	109.5	O3—Mo3—O10ⁱ	146.37 (9)
C10—C9—H9B	109.5	O2—Mo3—O8ⁱ	158.12 (11)
H9A—C9—H9B	109.5	O1—Mo3—O8ⁱ	95.34 (10)
C10—C9—H9C	109.5	O3—Mo3—O8ⁱ	78.99 (9)
H9A—C9—H9C	109.5	O10ⁱ—Mo3—O8ⁱ	72.51 (9)
H9B—C9—H9C	109.5	O2—Mo3—O4	85.84 (11)
N4—C10—N3	107.6 (5)	O1—Mo3—O4	165.57 (10)
N4—C10—C9	126.9 (4)	O3—Mo3—O4	83.04 (10)
N3—C10—C9	125.5 (5)	O10ⁱ—Mo3—O4	71.77 (8)
C16—C11—N4	134.1 (4)	O8ⁱ—Mo3—O4	72.51 (8)
C16—C11—C12	121.8 (5)	O2—Mo3—Mo1ⁱ	132.68 (10)
N4—C11—C12	104.1 (4)	O1—Mo3—Mo1ⁱ	86.67 (9)
N3—C12—C13	131.7 (5)	O3—Mo3—Mo1ⁱ	119.94 (7)
N3—C12—C11	107.1 (4)	O10ⁱ—Mo3—Mo1ⁱ	34.61 (6)
C13—C12—C11	121.1 (5)	O8ⁱ—Mo3—Mo1ⁱ	40.95 (6)
C14—C13—C12	116.6 (5)	O4—Mo3—Mo1ⁱ	79.05 (5)
C14—C13—H13	121.7	O12—Mo4—O13	106.33 (15)
C12—C13—H13	121.7	O12—Mo4—O6ⁱ	102.94 (12)
C13—C14—C15	123.2 (5)	O13—Mo4—O6ⁱ	98.20 (12)
C13—C14—H14	118.4	O12—Mo4—O3	104.89 (12)
C15—C14—H14	118.4	O13—Mo4—O3	97.98 (12)
C16—C15—C14	119.8 (6)	O6ⁱ—Mo4—O3	142.20 (11)
C16—C15—H15	120.1	O12—Mo4—O11	93.22 (12)
C14—C15—H15	120.1	O13—Mo4—O11	160.46 (12)
C11—C16—C15	117.4 (5)	O6ⁱ—Mo4—O11	76.92 (10)
C11—C16—H16	121.3	O3—Mo4—O11	76.46 (9)
C15—C16—H16	121.3	C2—N1—C3	110.6 (4)
O9—Mo1—O11	104.19 (13)	C2—N1—H1	124.7
O9—Mo1—O10	102.34 (10)	C3—N1—H1	124.7
O11—Mo1—O10	96.18 (11)	C2—N2—C4	110.0 (4)
O9—Mo1—O4	100.32 (10)	C2—N2—H2	125.0
O11—Mo1—O4	96.74 (10)	C4—N2—H2	125.0
O10—Mo1—O4	150.22 (9)	C10—N3—C12	110.0 (4)
O9—Mo1—O8	100.83 (12)	C10—N3—H3	125.0
O11—Mo1—O8	154.98 (10)	C12—N3—H3	125.0
O10—Mo1—O8	78.64 (9)	C10—N4—C11	111.2 (4)
O4—Mo1—O8	78.32 (9)	C10—N4—H4	124.4
O9—Mo1—O8ⁱ	175.91 (12)	C11—N4—H4	124.4
O11—Mo1—O8ⁱ	79.83 (10)	Mo3—O3—Mo4	117.45 (12)
O10—Mo1—O8ⁱ	77.76 (8)	Mo1—O4—Mo2	108.44 (11)
O4—Mo1—O8ⁱ	78.28 (8)	Mo1—O4—Mo3	109.11 (10)
O8—Mo1—O8ⁱ	75.15 (10)	Mo2—O4—Mo3	104.92 (9)
O9—Mo1—Mo3ⁱ	92.48 (9)	Mo2—O6—Mo4ⁱ	118.36 (13)
O11—Mo1—Mo3ⁱ	132.03 (7)	Mo1—O8—Mo2	93.48 (8)
O10—Mo1—Mo3ⁱ	35.91 (8)	Mo1—O8—Mo3ⁱ	92.93 (9)
O4—Mo1—Mo3ⁱ	124.42 (7)	Mo2—O8—Mo3ⁱ	162.00 (12)
O8—Mo1—Mo3ⁱ	46.11 (6)	Mo1—O8—Mo1ⁱ	104.85 (10)
O8ⁱ—Mo1—Mo3ⁱ	85.24 (5)	Mo2—O8—Mo1ⁱ	97.79 (8)
O9—Mo1—Mo2	90.71 (9)	Mo3ⁱ—O8—Mo1ⁱ	96.78 (8)
O11—Mo1—Mo2	132.94 (7)	Mo1—O10—Mo3ⁱ	109.48 (11)
O10—Mo1—Mo2	124.25 (7)	Mo1—O10—Mo2ⁱ	109.51 (9)
O4—Mo1—Mo2	36.25 (7)	Mo3ⁱ—O10—Mo2ⁱ	104.12 (9)
O8—Mo1—Mo2	45.61 (6)	Mo1—O11—Mo4	120.98 (12)
O8ⁱ—Mo1—Mo2	85.92 (6)

Symmetry code: (i) −x, −y, −z+2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O5ⁱⁱ	0.86	1.95	2.811 (4)	176
N2—H2···O13ⁱⁱⁱ	0.86	2.06	2.857 (4)	155
N3—H3···O1ⁱⁱ	0.86	1.99	2.752 (4)	147
N4—H4···O4^iv	0.86	2.30	3.089 (4)	154
N4—H4···O2^iv	0.86	2.41	3.060 (5)	133

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

Experimental details

Crystal data
Chemical formula	(C₈H₉N₂)₄[Mo₈O₂₆]
M_r	1716.21
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	296
a, b, c (Å)	10.4831 (12), 17.803 (2), 13.794 (2)
β (°)	112.305 (5)
V (Å³)	2381.6 (5)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	2.13
Crystal size (mm)	0.12 × 0.10 × 0.08

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2001)
T_min, T_max	0.784, 0.848
No. of measured, independent and observed [I > 2σ(I)] reflections	11151, 4167, 3566
R_int	0.043
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.022, 0.063, 1.00
No. of reflections	4167
No. of parameters	336
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.53, −0.59

Computer programs: APEX2 (Bruker, 2004), SAINT-Plus (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O5ⁱ	0.86	1.95	2.811 (4)	175.7
N2—H2···O13ⁱⁱ	0.86	2.06	2.857 (4)	154.7
N3—H3···O1ⁱ	0.86	1.99	2.752 (4)	147.0
N4—H4···O4ⁱⁱⁱ	0.86	2.30	3.089 (4)	153.5
N4—H4···O2ⁱⁱⁱ	0.86	2.41	3.060 (5)	133.0

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

Acknowledgements

Financial support from the International Cooperation Program for Excellent Lecturers of 2008 from Shandong Provincial Education Department, the Research Award Fund for Outstanding Young and Middle-aged Scientists of Shandong Province (2008BS04022), Shandong Provincial Education Department and Shandong Institute of Education are gratefully acknowledged.

References

Bruker (2001). SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2004). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chen, S.-M., Lu, C.-Z., Yu, Y.-Q., Zhang, Q.-Z. & He, X. (2004). Acta Cryst. E60, m723–m725. Web of Science CSD CrossRef IUCr Journals Google Scholar
Isobe, M., Marumo, F., Yamase, T. & Ikawa, T. (1978). Acta Cryst. B34, 2728–2731. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Li, J., Qi, Y. F., Wang, E. B., Li, J., Wang, H. F., Li, Y. G., Lu, Y., Hao, N., Xu, L. & Hu, C. W. (2004). J. Coord. Chem. 57, 715-720. Web of Science CSD CrossRef CAS Google Scholar
Lu, X. M., Li, W. J. & Mao, X. A. (2000). Chinese J.Struct.Chem. (Jiegou Huaxue), 19, 163–167. CAS Google Scholar
Pope, M. T. & Müller, A. (1991). Angew. Chem. Int. Ed. 30, 34–38. CrossRef Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Zhang, X. T., Dou, J. M., Wei, P. H., Li, D. C., Li, B., Shi, C. W. & Hu, B. (2009). Inorg. Chim. Acta, 362, 3325–3332. Web of Science CSD CrossRef CAS Google Scholar
Zhang, X. T., Wei, P. H., Sun, D. F., Ni, Z. H., Dou, J. M., Li, B., Shi, C. W. & Hu, B. (2009). Cryst. Growth Des. 9, 4424–4428. Web of Science CSD CrossRef CAS Google Scholar