Tetra-μ-oxido-tetra­kis{dioxido[3-(2-pyrid­yl)-1H-pyrazole]molybdenum(VI)}

Li, D.; Liu, Y.; Wei, P.; Hu, B.; Zhang, X.

doi:10.1107/S1600536809031717

metal-organic compounds

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ISSN: 2056-9890

Volume 65| Part 9| September 2009| Page m1074

doi:10.1107/S1600536809031717

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Tetra-μ-oxido-tetrakis{dioxido[3-(2-pyridyl)-1H-pyrazole]molybdenum(VI)}

Dacheng Li,^a Ying Liu,^a Peihai Wei,^b Bo Hu ^b and Xiutang Zhang ^a,^b ^*

^aCollege of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, People's Republic of China, and ^bAdvanced Material Institute of Research, Department of Chemistry and Chemical Engineering, ShanDong Institute of Education, Jinan 250013, People's Republic of China
^*Correspondence e-mail: xiutangzhang@yahoo.com.cn

(Received 28 July 2009; accepted 11 August 2009; online 15 August 2009)

In the title compound, [Mo₄O₁₂(C₈H₇N₃)₄], the Mo^VI ion has a distorted octahedral coordination completed by two terminal O atoms, two μ-oxide atoms and two N atoms from one 3-(2-pyridyl)-1H-pyrazole ligand. It is noteworthy that in the tetranuclear unit ( $[\overline4]$ symmetry), any three Mo^VI atoms define a plane, and the fourth lies 1.8 (1) Å out of that plane. The degree of linearity of the oxide bridges between two Mo atoms is 175.38 (13)°. Moreover, the N—H group forms an intramolecular hydrogen bond (four per molecule).

Related literature

For the properties and potential medical applications of polyoxometalate clusters, see: Pope & Müller (1991 ); Khenkin & Neumann (2008 ); Zhang et al. (2006 , 2007 , 2009 ). For Mo—O and Mo—N distances, see: Rana et al. (2003 ). For general background, see: Mezei et al. (2007 ).

Experimental

Crystal data

[Mo₄O₁₂(C₈H₇N₃)₄]
M_r = 1156.42
Tetragonal, P 4₂ /n
a = 14.4412 (16) Å
c = 9.094 (2) Å
V = 1896.6 (5) Å³
Z = 2
Mo Kα radiation
μ = 1.37 mm⁻¹
T = 298 K
0.12 × 0.10 × 0.08 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ) T_min = 0.853, T_max = 0.898
7579 measured reflections
1675 independent reflections
1316 reflections with I > 2σ(I)
R_int = 0.036

Refinement

R[F² > 2σ(F²)] = 0.024
wR(F²) = 0.064
S = 1.00
1675 reflections
139 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.35 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H1A⋯O2ⁱ	0.94 (5)	1.86 (5)	2.783 (4)	168 (4)
Symmetry code: (i) $[y, -x+{\script{3\over 2}}, -z+{\script{1\over 2}}]$ .

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: 10.1107/S1600536809031717/zq2001sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809031717/zq2001Isup2.hkl

checkCIF report

Comment top

The design and synthesis of polyoxometalate clusters has attracted continuous research interest not only because of their appealing structural and topological novelty, but also due to their unusual optical, electronic, magnetic, and catalytic properties, as well as their potential medical application (Pope et al.; Khenkin et al.; Zhang et al. (2007); Zhang et al. (2006); Zhang et al. (2009). In the present paper, we describe the synthesis and structural characterization of tetrakis((µ-oxo)-bis(3-(2-pyridyl)pyrazole)molybdenum(vi)).

In the asymmetric unit of complex I, there exhibit one 3-(2-pyridyl)pyrazole ligand and one molybdenum oxide Mo^VIO₃, Fig. 1. The Mo^VI ion surrounded by one 3-(2-pyridyl)pyrazole ligand is hexa-coordinated by four oxygen atoms and two nitrogen atoms, with distorted octahedral coordination sphere. The bond distances of Mo—O and Mo—N are in the normal range compared to the reported complexes containing the N—Mo—O atoms (Rana et al.). It is worthy noting that the simple basic Mo₃HL units are assembled to form one 8-MC-4 complex, which could be described as `folded' with two adjacent Mo₃ planes forming a dihedral angle of about 38.65°. Moreover, the N—H group forms a very nice intramolecular hydrogen bond (4 per molecule), shown in Fig. 2.

Related literature top

For the properties and potential medical applications of polyoxometalate clusters, see: Pope et al. (1991); Khenkin et al. (2008); Zhang et al. (2006, 2007, 2009). For Mo—O and Mo—N distances, see: Rana et al. (2003). For related literature, see: Mezei et al. (2007);

Zhang et al. (2006).

Experimental top

A mixture of 3-(2-pyridyl)pyrazole (1 mmoL) and molybdenum trioxide (1 mmoL) in 10 ml distilled water sealed in a 25 ml Teflon-lined stainless steel autoclave was kept at 433 K for three days. Colourless crystals suitable for an X-ray experiment were obtained. Anal. Calc. for C₃₂H₂₈Mo₄N₁₂O₁₂: C 33.22, H 1.90, N 14.53%; Found: C 33.13, H 1.79, N 14.32%.

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. A view of the title compound with the unique atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. The packing diagram of the title compound with the hydrogen bonds of N2—H1A···O2.

Tetra-µ-oxido-tetrakis{dioxido[3-(2-pyridyl)-1H-pyrazole]molybdenum(VI)} top

Crystal data top

[Mo₄O₁₂(C₈H₇N₃)₄]	D_x = 2.025 Mg m⁻³
M_r = 1156.42	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4₂/n	Cell parameters from 1675 reflections
Hall symbol: -P 4bc	θ = 2.0–25.0°
a = 14.4412 (16) Å	µ = 1.37 mm⁻¹
c = 9.094 (2) Å	T = 298 K
V = 1896.6 (5) Å³	Block, colourless
Z = 2	0.12 × 0.10 × 0.08 mm
F(000) = 1136

Data collection top

Bruker APEXII CCD area-detector diffractometer	1675 independent reflections
Radiation source: fine-focus sealed tube	1316 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.036
ϕ and ω scans	θ_max = 25.0°, θ_min = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −17→16
T_min = 0.853, T_max = 0.898	k = −12→17
7579 measured reflections	l = −9→10

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)] = 0.024	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.064	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	w = 1/[σ²(F_o²) + (0.0295P)² + 2.0306P] where P = (F_o² + 2F_c²)/3
1675 reflections	(Δ/σ)_max = 0.001
139 parameters	Δρ_max = 0.35 e Å⁻³
1 restraint	Δρ_min = −0.35 e Å⁻³

Crystal data top

[Mo₄O₁₂(C₈H₇N₃)₄]	Z = 2
M_r = 1156.42	Mo Kα radiation
Tetragonal, P4₂/n	µ = 1.37 mm⁻¹
a = 14.4412 (16) Å	T = 298 K
c = 9.094 (2) Å	0.12 × 0.10 × 0.08 mm
V = 1896.6 (5) Å³

Data collection top

Bruker APEXII CCD area-detector diffractometer	1675 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2001)	1316 reflections with I > 2σ(I)
T_min = 0.853, T_max = 0.898	R_int = 0.036
7579 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.024	1 restraint
wR(F²) = 0.064	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	Δρ_max = 0.35 e Å⁻³
1675 reflections	Δρ_min = −0.35 e Å⁻³
139 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
Mo1	0.642839 (18)	0.904662 (19)	0.19761 (3)	0.02233 (12)
N1	0.61994 (19)	0.90081 (18)	0.4404 (3)	0.0257 (6)
N2	0.6811 (2)	0.8938 (2)	0.5516 (3)	0.0311 (7)
N3	0.4862 (2)	0.8976 (2)	0.2532 (3)	0.0314 (7)
O1	0.76035 (15)	0.88536 (16)	0.2362 (2)	0.0302 (5)
O2	0.61894 (17)	0.86807 (17)	0.0193 (3)	0.0359 (6)
O3	0.63381 (18)	1.02324 (17)	0.1907 (3)	0.0370 (6)
C1	0.6375 (3)	0.8821 (3)	0.6815 (4)	0.0345 (9)
H1	0.6656	0.8765	0.7731	0.041*
C2	0.5439 (3)	0.8800 (2)	0.6536 (4)	0.0354 (9)
H2A	0.4963	0.8726	0.7215	0.042*
C3	0.5355 (2)	0.8917 (2)	0.4995 (4)	0.0283 (8)
C4	0.4595 (2)	0.8907 (2)	0.3953 (4)	0.0321 (8)
C5	0.3667 (3)	0.8828 (2)	0.4346 (5)	0.0413 (10)
H5	0.3492	0.8796	0.5329	0.050*
C6	0.3014 (3)	0.8798 (3)	0.3248 (5)	0.0519 (11)
H6	0.2391	0.8724	0.3477	0.062*
C7	0.3291 (3)	0.8878 (3)	0.1802 (5)	0.0504 (11)
H7	0.2853	0.8870	0.1054	0.060*
C8	0.4208 (3)	0.8969 (3)	0.1471 (5)	0.0423 (10)
H8	0.4386	0.9027	0.0492	0.051*
H1A	0.746 (3)	0.894 (3)	0.540 (5)	0.080*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Mo1	0.02453 (18)	0.02550 (18)	0.01698 (17)	0.00112 (12)	0.00115 (11)	0.00047 (12)
N1	0.0347 (15)	0.0237 (14)	0.0187 (14)	0.0010 (12)	−0.0011 (12)	−0.0010 (11)
N2	0.0367 (17)	0.0338 (16)	0.0227 (16)	0.0002 (14)	0.0014 (13)	−0.0026 (13)
N3	0.0298 (16)	0.0315 (16)	0.0328 (16)	0.0037 (13)	−0.0038 (13)	−0.0050 (13)
O1	0.0245 (12)	0.0387 (14)	0.0273 (13)	0.0000 (11)	0.0026 (10)	0.0028 (11)
O2	0.0466 (15)	0.0403 (14)	0.0209 (13)	−0.0016 (12)	−0.0022 (11)	0.0006 (11)
O3	0.0448 (15)	0.0294 (13)	0.0368 (15)	0.0040 (11)	0.0047 (12)	0.0037 (11)
C1	0.044 (2)	0.039 (2)	0.0201 (19)	0.0018 (17)	0.0019 (16)	0.0017 (16)
C2	0.041 (2)	0.034 (2)	0.031 (2)	0.0022 (17)	0.0135 (17)	0.0045 (16)
C3	0.0357 (19)	0.0203 (17)	0.0289 (19)	0.0051 (14)	0.0086 (16)	−0.0006 (14)
C4	0.036 (2)	0.0216 (17)	0.039 (2)	0.0017 (15)	0.0111 (17)	0.0006 (16)
C5	0.034 (2)	0.035 (2)	0.055 (3)	0.0049 (17)	0.0090 (19)	0.0055 (19)
C6	0.033 (2)	0.055 (3)	0.067 (3)	0.0006 (19)	0.002 (2)	0.003 (2)
C7	0.033 (2)	0.067 (3)	0.051 (3)	0.005 (2)	−0.010 (2)	−0.007 (2)
C8	0.036 (2)	0.046 (2)	0.044 (2)	0.0043 (18)	−0.0021 (18)	−0.0070 (19)

Geometric parameters (Å, º) top

Mo1—O3	1.719 (2)	C1—C2	1.375 (5)
Mo1—O2	1.740 (2)	C1—H1	0.9300
Mo1—O1	1.755 (2)	C2—C3	1.416 (5)
Mo1—O1ⁱ	2.207 (2)	C2—H2A	0.9300
Mo1—N1	2.233 (3)	C3—C4	1.449 (5)
Mo1—N3	2.320 (3)	C4—C5	1.392 (5)
N1—C3	1.340 (4)	C5—C6	1.374 (6)
N1—N2	1.346 (4)	C5—H5	0.9300
N2—C1	1.349 (4)	C6—C7	1.379 (6)
N2—H1A	0.94 (5)	C6—H6	0.9300
N3—C8	1.350 (5)	C7—C8	1.364 (6)
N3—C4	1.353 (5)	C7—H7	0.9300
O1—Mo1ⁱⁱ	2.207 (2)	C8—H8	0.9300

O3—Mo1—O2	104.69 (12)	N2—C1—C2	107.4 (3)
O3—Mo1—O1	103.82 (11)	N2—C1—H1	126.3
O2—Mo1—O1	109.26 (11)	C2—C1—H1	126.3
O3—Mo1—O1ⁱ	159.53 (10)	C1—C2—C3	105.4 (3)
O2—Mo1—O1ⁱ	86.03 (10)	C1—C2—H2A	127.3
O1—Mo1—O1ⁱ	88.51 (13)	C3—C2—H2A	127.3
O3—Mo1—N1	92.85 (10)	N1—C3—C2	109.3 (3)
O2—Mo1—N1	152.17 (11)	N1—C3—C4	115.3 (3)
O1—Mo1—N1	86.65 (10)	C2—C3—C4	135.3 (3)
O1ⁱ—Mo1—N1	71.30 (9)	N3—C4—C5	121.7 (4)
O3—Mo1—N3	88.74 (11)	N3—C4—C3	114.1 (3)
O2—Mo1—N3	89.78 (11)	C5—C4—C3	124.2 (3)
O1—Mo1—N3	153.15 (10)	C6—C5—C4	118.4 (4)
O1ⁱ—Mo1—N3	73.68 (9)	C6—C5—H5	120.8
N1—Mo1—N3	68.85 (10)	C4—C5—H5	120.8
C3—N1—N2	106.7 (3)	C5—C6—C7	119.5 (4)
C3—N1—Mo1	122.3 (2)	C5—C6—H6	120.3
N2—N1—Mo1	130.4 (2)	C7—C6—H6	120.3
N1—N2—C1	111.2 (3)	C8—C7—C6	120.0 (4)
N1—N2—H1A	124 (3)	C8—C7—H7	120.0
C1—N2—H1A	124 (3)	C6—C7—H7	120.0
C8—N3—C4	118.9 (3)	N3—C8—C7	121.4 (4)
C8—N3—Mo1	121.8 (3)	N3—C8—H8	119.3
C4—N3—Mo1	119.3 (2)	C7—C8—H8	119.3
Mo1—O1—Mo1ⁱⁱ	175.38 (13)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H1A···O2ⁱⁱ	0.94 (5)	1.86 (5)	2.783 (4)	168 (4)

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

Experimental details

Crystal data
Chemical formula	[Mo₄O₁₂(C₈H₇N₃)₄]
M_r	1156.42
Crystal system, space group	Tetragonal, P4₂/n
Temperature (K)	298
a, c (Å)	14.4412 (16), 9.094 (2)
V (Å³)	1896.6 (5)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	1.37
Crystal size (mm)	0.12 × 0.10 × 0.08

Data collection
Diffractometer	Bruker APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2001)
T_min, T_max	0.853, 0.898
No. of measured, independent and observed [I > 2σ(I)] reflections	7579, 1675, 1316
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.024, 0.064, 1.00
No. of reflections	1675
No. of parameters	139
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.35, −0.35

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
N2—H1A···O2ⁱ	0.94 (5)	1.86 (5)	2.783 (4)	168 (4)

Symmetry code: (i) y, −x+3/2, −z+1/2.

Acknowledgements

Financial support from the Natural Science Foundation of China (grant No. 20171028, 20325105), the National Ministry of Science and Technology of China (grant No. 2001CB6105-07) and the Ministry of Education of China, Shandong University, is gratefully acknowledged.

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