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The title compound, [Mo2O6(pz)]n (pz is pyrazine, C4H4N2), was synthisized by hydrothermal reaction of MoO3, pyrazine-2-carboxylic acid and water at 443 K. The compound is a three-dimensional inorganic–organic hybrid polymer, in which pz acts as a bridging ligand. Each Mo atom is coordinated by five O atoms and one N atom in a distorted octahedral geometry, with the Mo—N distance being 2.449 (8) Å and the Mo—O distances ranging from 1.682 (7) to 2.086 (8) Å.
Supporting information
CCDC reference: 162802
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.012 Å
- R factor = 0.034
- wR factor = 0.086
- Data-to-parameter ratio = 10.9
checkCIF results
No syntax errors found
ADDSYM reports no extra symmetry
Alert Level C:
PLAT_214 Alert C Atom O1 (Anion/Solvent) ADP max/min Ratio 4.60
PLAT_214 Alert C Atom O2 (Anion/Solvent) ADP max/min Ratio 4.10
General Notes
ABSTM_02 When printed, the submitted absorption T values will be replaced
by the scaled T values. Since the ratio of scaled T's is
identical to the ratio of reported T values, the scaling does
not imply a change to the absorption corrections used in the
study.
Ratio of Tmax expected/reported 0.825
Tmax scaled 0.825 Tmin scaled 0.673
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
2 Alert Level C = Please check
A mixture of MoO3 (144 mg), pyrazine-2-carboxylic acid (124 mg) and water (16 ml) was sealed in a 25 ml Teflon-lined stainless-steel reactor, heated to 443 K for 72 h, then naturally cooled to room temperature. Block-shaped black
crystals suitable for X-ray analysis were obtained in 70% yield.
Data collection: SMART (Siemens, 1994); cell refinement: SMART; data reduction: SMART; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Crystal data top
[Mo2)6(C4H4N2)] | Dx = 3.113 Mg m−3 |
Mr = 367.98 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pbca | Cell parameters from 2590 reflections |
a = 7.566 (16) Å | θ = 2.9–25.1° |
b = 7.39 (2) Å | µ = 3.20 mm−1 |
c = 14.04 (3) Å | T = 293 K |
V = 785 (3) Å3 | Block, black |
Z = 4 | 0.10 × 0.10 × 0.06 mm |
F(000) = 348 | |
Data collection top
Siemens Smart CCD diffractometer | 695 independent reflections |
Radiation source: fine-focus sealed tube | 630 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.027 |
ω scans | θmax = 25.1°, θmin = 2.9° |
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996) | h = −9→8 |
Tmin = 0.816, Tmax = 1.000 | k = −3→8 |
3627 measured reflections | l = −16→13 |
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)] = 0.035 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.086 | H-atom parameters constrained |
S = 1.24 | w = 1/[σ2(Fo2) + 18.7425P] where P = (Fo2 + 2Fc2)/3 |
695 reflections | (Δ/σ)max < 0.001 |
64 parameters | Δρmax = 1.09 e Å−3 |
0 restraints | Δρmin = −1.11 e Å−3 |
Crystal data top
[Mo2)6(C4H4N2)] | V = 785 (3) Å3 |
Mr = 367.98 | Z = 4 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 7.566 (16) Å | µ = 3.20 mm−1 |
b = 7.39 (2) Å | T = 293 K |
c = 14.04 (3) Å | 0.10 × 0.10 × 0.06 mm |
Data collection top
Siemens Smart CCD diffractometer | 695 independent reflections |
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996) | 630 reflections with I > 2σ(I) |
Tmin = 0.816, Tmax = 1.000 | Rint = 0.027 |
3627 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.035 | 0 restraints |
wR(F2) = 0.086 | H-atom parameters constrained |
S = 1.24 | w = 1/[σ2(Fo2) + 18.7425P] where P = (Fo2 + 2Fc2)/3 |
695 reflections | Δρmax = 1.09 e Å−3 |
64 parameters | Δρmin = −1.11 e Å−3 |
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 | Uiso*/Ueq | |
Mo | 0.53153 (8) | 0.04406 (8) | 0.72799 (5) | 0.0094 (3) | |
N1 | 0.5163 (10) | 0.0231 (9) | 0.9018 (5) | 0.0180 (15) | |
O1 | 0.7602 (9) | 0.0276 (13) | 0.7470 (4) | 0.049 (2) | |
O2 | 0.5002 (13) | 0.2812 (8) | 0.7518 (5) | 0.049 (2) | |
O3 | 0.5142 (7) | 0.0367 (8) | 0.6086 (4) | 0.0177 (13) | |
C1 | 0.6160 (12) | −0.0961 (11) | 0.9494 (6) | 0.0179 (18) | |
H1A | 0.6982 | −0.1651 | 0.9162 | 0.021* | |
C2 | 0.3998 (11) | 0.1193 (11) | 0.9540 (6) | 0.0159 (17) | |
H2A | 0.3281 | 0.2038 | 0.9237 | 0.019* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Mo | 0.0079 (4) | 0.0078 (4) | 0.0124 (4) | 0.0002 (3) | 0.0009 (3) | 0.0004 (3) |
N1 | 0.025 (4) | 0.017 (4) | 0.012 (3) | 0.000 (3) | −0.002 (3) | 0.002 (3) |
O1 | 0.006 (3) | 0.121 (7) | 0.021 (3) | 0.003 (4) | −0.002 (3) | −0.001 (4) |
O2 | 0.117 (7) | 0.007 (3) | 0.022 (3) | 0.003 (4) | 0.002 (4) | 0.001 (3) |
O3 | 0.017 (3) | 0.021 (3) | 0.015 (3) | 0.000 (3) | −0.001 (2) | −0.001 (2) |
C1 | 0.023 (5) | 0.008 (4) | 0.022 (4) | 0.003 (3) | 0.004 (4) | −0.003 (3) |
C2 | 0.014 (4) | 0.013 (4) | 0.020 (4) | 0.004 (3) | −0.001 (3) | 0.003 (4) |
Geometric parameters (Å, º) top
Mo—O3 | 1.682 (7) | N1—C1 | 1.338 (11) |
Mo—O1 | 1.755 (7) | N1—C2 | 1.349 (11) |
Mo—O2 | 1.799 (8) | O1—Moiii | 2.086 (8) |
Mo—O2i | 1.976 (9) | O2—Moiv | 1.976 (9) |
Mo—O1ii | 2.086 (8) | C1—C2v | 1.372 (12) |
Mo—N1 | 2.449 (8) | C2—C1v | 1.372 (12) |
| | | |
O3—Mo—O1 | 103.1 (3) | O1—Mo—N1 | 83.7 (3) |
O3—Mo—O2 | 101.9 (3) | O2—Mo—N1 | 82.5 (3) |
O1—Mo—O2 | 99.7 (5) | O2i—Mo—N1 | 77.8 (3) |
O3—Mo—O2i | 95.9 (3) | O1ii—Mo—N1 | 77.4 (2) |
O1—Mo—O2i | 91.7 (4) | C1—N1—C2 | 116.3 (7) |
O2—Mo—O2i | 156.01 (9) | C1—N1—Mo | 120.9 (6) |
O3—Mo—O1ii | 95.1 (3) | C2—N1—Mo | 122.6 (5) |
O1—Mo—O1ii | 160.1 (2) | Mo—O1—Moiii | 172.6 (6) |
O2—Mo—O1ii | 84.0 (4) | Mo—O2—Moiv | 177.5 (4) |
O2i—Mo—O1ii | 78.4 (4) | N1—C1—C2v | 121.8 (8) |
O3—Mo—N1 | 171.0 (3) | N1—C2—C1v | 121.9 (8) |
Symmetry codes: (i) −x+1, y−1/2, −z+3/2; (ii) x−1/2, y, −z+3/2; (iii) x+1/2, y, −z+3/2; (iv) −x+1, y+1/2, −z+3/2; (v) −x+1, −y, −z+2. |
Experimental details
Crystal data |
Chemical formula | [Mo2)6(C4H4N2)] |
Mr | 367.98 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 293 |
a, b, c (Å) | 7.566 (16), 7.39 (2), 14.04 (3) |
V (Å3) | 785 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 3.20 |
Crystal size (mm) | 0.10 × 0.10 × 0.06 |
|
Data collection |
Diffractometer | Siemens Smart CCD diffractometer |
Absorption correction | Empirical (using intensity measurements) (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.816, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3627, 695, 630 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.597 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.035, 0.086, 1.24 |
No. of reflections | 695 |
No. of parameters | 64 |
H-atom treatment | H-atom parameters constrained |
| w = 1/[σ2(Fo2) + 18.7425P] where P = (Fo2 + 2Fc2)/3 |
Δρmax, Δρmin (e Å−3) | 1.09, −1.11 |
Selected geometric parameters (Å, º) topMo—O3 | 1.682 (7) | Mo—O2 | 1.799 (8) |
Mo—O1 | 1.755 (7) | Mo—N1 | 2.449 (8) |
| | | |
O3—Mo—O1 | 103.1 (3) | O2—Mo—O1ii | 84.0 (4) |
O3—Mo—O2 | 101.9 (3) | O2i—Mo—O1ii | 78.4 (4) |
O1—Mo—O2 | 99.7 (5) | O3—Mo—N1 | 171.0 (3) |
O3—Mo—O2i | 95.9 (3) | O1—Mo—N1 | 83.7 (3) |
O1—Mo—O2i | 91.7 (4) | O2—Mo—N1 | 82.5 (3) |
O2—Mo—O2i | 156.01 (9) | O2i—Mo—N1 | 77.8 (3) |
O3—Mo—O1ii | 95.1 (3) | O1ii—Mo—N1 | 77.4 (2) |
O1—Mo—O1ii | 160.1 (2) | | |
Symmetry codes: (i) −x+1, y−1/2, −z+3/2; (ii) x−1/2, y, −z+3/2. |
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Owing to the important role in the development of catalysis, electric conductivity, magnetism, non-linear optical properties and medicine, metal oxide chemistry has attracted much interest in recent years (Hill, 1998). In order to study the reaction behavior of metal oxides, organoamine ligands were often selected for the construction of inorganic–organic hybrid materials. Organoamines act in three different roles in these inorganic–organic hybrid materials: (i) as charge-compensating cations, (ii) directly bonded to the metal site of the metal oxide skeleton backbone and (iii) bonded to the heterometal atom. Recently, Zubieta and co-workers choose organoamines as a ligand and reported several molybdenum oxide hybrid materials compounds (Zubieta et al., 1999), such as MoO3(2,2'-bpy), Mo2O6(2,2'-bpy), Mo3O9(2,2'-bpy)2, Mo4O13(Hbpa), (H2en)Mo3O10 and [H3N(CH2)6NH3][Mo4O13] with a one-dimensional chain structure (Zubieta et al., 1993, 1997; Zapf et al., 1998; Xu et al., 1996); two-dimensional structure compounds [4,4'-H2bpy][Mo7O22]·H2O (Zapf et al., 1997a,b) and MO3(py) (M = Mo,W) (Johnson et al., 1981) and a three-dimensional network structure HMo2O6(4,4'-bpy). Herein we report the crystal structure of a molybdenum trioxide–pyrazine complex possessing a three-dimensional framework structure prepared via hydrothermal reaction, i.e. Mo3(pz)0.5.
The title compound, (I), consists of Mo2O6 and pyrazine. Mo2O6 forms a two-dimensional layer structure by sharing O atoms. The two-dimensional layer is linked further into three-dimensional framework through pyrazine bridging ligands. In the title compound, pyrazine came from the heat decarboxylated reaction of the pyrazine-2-carboxylic acid. Every MoVI atom was coordinated by five O atoms and one pyrazine N atom to form an [MoO5N] octahedral geometry. The Mo—O bond lengths range from 1.682 (7) to 2.086 (8) Å and the Mo—N distance is 2.449 (8) Å. The O—Mo—O angles range from 78.4 (4) to 160.1 (2)° and the O—Mo—N angles range from 77.4 (2) to 171.0 (3)°.