organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890
Volume 70| Part 9| September 2014| Pages o893-o894

Crystal structure of 2,5-bis­­(4-methyl­pyridin-2-yl)pyrazine chloro­form disolvate

aInstitute of Physics, University of Neuchâtel, rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
*Correspondence e-mail: helen.stoeckli-evans@unine.ch

Edited by M. Weil, Vienna University of Technology, Austria (Received 24 April 2014; accepted 24 April 2014; online 1 August 2014)

The heterocyclic molecule in the title solvate, C16H14N4·2CHCl3, possesses inversion symmetry, with the inversion centre situated at the centre of the pyrazine ring. The outer pyridine rings are inclined to the central pyrazine ring by 4.89 (9)°. The compound crystallized as a chloro­form disolvate with the solvent mol­ecules linked to the title mol­ecule by C—H⋯N hydrogen bonds. In the crystal, mol­ecules are further linked by ππ inter­actions involving the pyrazine and pyridine rings of neighbouring mol­ecules [inter-centroid distance = 3.5629 (12) Å; symmetry code: x, y + 1, z + 1].

1. Related literature

The title compound is the 4-methyl­pyridine derivative of the ligand 2,5-bis­(pyridin-2-yl)pyrazine (bppz), see: Neels & Stoeckli-Evans (1993[Neels, A. & Stoeckli-Evans, H. (1993). Chimia, 47, 198-202.]); Schmitt (2008[Schmitt, L. (2008). PhD thesis, University of Neuchâtel, Switzerland.]). For the synthesis of a number of transition-metal complexes of bppz, especially of copper(II), and for their magnetic properties, see for example: Escuer et al. (1993[Escuer, A., Comas, T., Vicente, R. & Ribas, J. (1993). Transition Met. Chem. 18, 42-44.]); Neels et al. (1995[Neels, A., Stoeckli-Evans, H., Escuer, A. & Vi, R. (1995). Inorg. Chem. 34, 1946-1949.]); Yuste et al. (2009[Yuste, C., Bentama, A., Marino, N., Armentano, D., Setifi, F., Triki, S., Lloret, F. & Julve, M. (2009). Polyhedron, 28, 1287-1294.]); Bentama et al. (2012[Bentama, A., Schott, O., Ferrando-Soria, J., Stiriba, S.-E., Pasán, J., Ruiz-Pérez, C. & Julve, M. (2012). Inorg. Chim. Acta, 389, 52-59.]).

[Scheme 1]

2. Experimental

2.1. Crystal data

  • C16H14N4·2CHCl3

  • Mr = 501.05

  • Monoclinic, I 2/a

  • a = 16.4498 (17) Å

  • b = 6.0691 (4) Å

  • c = 21.605 (3) Å

  • β = 93.885 (9)°

  • V = 2152.0 (4) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.81 mm−1

  • T = 173 K

  • 0.45 × 0.29 × 0.23 mm

2.2. Data collection

  • Stoe IPDS 2 diffractometer

  • Absorption correction: multi-scan (MULscanABS in PLATON; Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) Tmin = 0.567, Tmax = 1.000

  • 9566 measured reflections

  • 1902 independent reflections

  • 1676 reflections with I > 2σ(I)

  • Rint = 0.066

2.3. Refinement

  • R[F2 > 2σ(F2)] = 0.040

  • wR(F2) = 0.112

  • S = 1.06

  • 1902 reflections

  • 129 parameters

  • H-atom parameters constrained

  • Δρmax = 0.31 e Å−3

  • Δρmin = −0.30 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C10—H10⋯N1 1.00 2.50 3.335 (3) 141

Data collection: X-AREA (Stoe & Cie, 2009[Stoe & Cie (2009). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany.]); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2009[Stoe & Cie (2009). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]); software used to prepare material for publication: SHELXL2013, PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Experimental top

Synthesis and crystallization top

The title compound was prepared in 3 stages:

Stage 1. Synthesis of methyl-2-pyridine-4-methyl-ketoxime (1): Hydroxyl­amine hydro­chloride (566 mg, 8.14 mmol) in pyridine (5ml) was added to a solution of 2-acetyl-4-methyl­pyrine (1.0 g, 7.40 mmol) in pyridine (22 ml) with vigorous stirring for 3 h at room temperature. The colourless solution was then poured into iced water. The oxime that precipitated was filtered and then dried under vacuum, yielding 1.33 g of compound (1) as a white powder. MS (ESI) calc. for C8H10N2O [M+H]+ : 150.18; found 151.1.

Stage 2. Synthesis of methyl-p-tosyl-2-actelypyridine oxime (2): Tosyl chloride (2.40 g, 7.32 mmol) was added to a solution of (1) [1.0 g, 6.6 mmol] in pyridine (10 ml) with stirring for 20 h. The orange solution obtained was poured into iced water. A white precipitate was obtained which was filtered, washed with cold water and dried, yielding compound (2) as a white powder [Yield 74%; 523 mg]. MS (ESI) calc. for C15H16N2O3S [M+H]+: 304.36; found 305.1.

Stage 3. Synthesis of 2,5-bis­(4-methyl-2-yl)-pyrazine: Potassium tert-butoxide (516 mg, 4.60 mmol) was added in small portions to a solution of (2) [1.0 g, 3.286 mmol] in dry ethanol (15 ml). The mixture was stirred at room temperature for 20 h. The precipitate of potassium p-toluene­sulfonate that formed was filtered off and washed with ether. The filtrate and the washed fractions were collected. This process was repeated until no further precipitation occurred. An aqueous solution of hydrogen peroxide (30%, 4 ml) was then added to the assembled filtrates and washed fractions. When the exothermic reaction had stopped, the mixture was placed in a refrigerator over night yielding the title compound. It was filtered off and washed with water/methanol (1/1, v/v) and dried (yield 5%, 43 mg). MS (ESI) calc. for C16H14N4 [M+H]+: 262.31, found 263.13. The colourless rod-like crystals used for X-ray diffraction analysis were obtained by slow evaporation of a solution in chloro­form.

Refinement top

The C-bound H atoms were included in calculated positions and treated as riding atoms: C—H = 0.95 - 1.00 Å with Uiso(H) = 1.5Ueq(C-methyl) and = 1.2Ueq(C) for other H atoms.

Related literature top

The title compound is the 4-methylpyridine derivative of the ligand 2,5-bis(pyridin-2-yl)pyrazine (bppz), see: Neels & Stoeckli-Evans (1993); Schmitt (2008). For the synthesis of a number of transition-metal complexes of bppz, especially of copper(II), and for their magnetic properties, see for example: Escuer et al. (1993); Neels et al. (1995); Yuste et al. (2009); Bentama et al. (2012).

Computing details top

Data collection: X-AREA (Stoe & Cie, 2009); cell refinement: X-AREA (Stoe & Cie, 2009); data reduction: X-RED32 (Stoe & Cie, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2013 (Sheldrick, 2008), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. A view of the molecular structure of the title compound, with atom labelling [unlabelled atoms are generated by inversion symmetry (symmetry code: -x + 3/2, -y + 3/2, -z + 1/2)]. Displacement ellipsoids are drawn at the 50% probability level. The C—H···N hydrogen bonds are shown as dashed lines (see Table 1 for details).
[Figure 2] Fig. 2. A view of the crystal packing of the title compound, illustrating the overlap of the pyrazine and pyridine rings of neighbouring molecules.
2,5-Bis(4-methylpyridin-2-yl)pyrazine chloroform disolvate top
Crystal data top
C16H14N4·2CHCl3F(000) = 1016
Mr = 501.05Dx = 1.546 Mg m3
Monoclinic, I2/aMo Kα radiation, λ = 0.71073 Å
a = 16.4498 (17) ÅCell parameters from 12496 reflections
b = 6.0691 (4) Åθ = 1.5–25.6°
c = 21.605 (3) ŵ = 0.81 mm1
β = 93.885 (9)°T = 173 K
V = 2152.0 (4) Å3Rod, colourless
Z = 40.45 × 0.29 × 0.23 mm
Data collection top
Stoe IPDS 2
diffractometer
1902 independent reflections
Radiation source: fine-focus sealed tube1676 reflections with I > 2σ(I)
Plane graphite monochromatorRint = 0.066
ϕ + ω scansθmax = 25.2°, θmin = 1.9°
Absorption correction: multi-scan
(MULscanABS in PLATON; Spek, 2009)
h = 1919
Tmin = 0.567, Tmax = 1.000k = 77
9566 measured reflectionsl = 2525
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.040 w = 1/[σ2(Fo2) + (0.0725P)2 + 0.8241P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.112(Δ/σ)max = 0.002
S = 1.06Δρmax = 0.31 e Å3
1902 reflectionsΔρmin = 0.30 e Å3
129 parametersExtinction correction: SHELXL2013 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.0064 (11)
Crystal data top
C16H14N4·2CHCl3V = 2152.0 (4) Å3
Mr = 501.05Z = 4
Monoclinic, I2/aMo Kα radiation
a = 16.4498 (17) ŵ = 0.81 mm1
b = 6.0691 (4) ÅT = 173 K
c = 21.605 (3) Å0.45 × 0.29 × 0.23 mm
β = 93.885 (9)°
Data collection top
Stoe IPDS 2
diffractometer
1902 independent reflections
Absorption correction: multi-scan
(MULscanABS in PLATON; Spek, 2009)
1676 reflections with I > 2σ(I)
Tmin = 0.567, Tmax = 1.000Rint = 0.066
9566 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0400 restraints
wR(F2) = 0.112H-atom parameters constrained
S = 1.06Δρmax = 0.31 e Å3
1902 reflectionsΔρmin = 0.30 e Å3
129 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.72397 (10)0.6344 (3)0.19653 (8)0.0368 (4)
N20.89303 (10)0.2947 (3)0.25318 (8)0.0394 (4)
C10.68638 (12)0.8157 (3)0.21400 (9)0.0374 (4)
H10.64060.86770.18900.045*
C20.78878 (11)0.5676 (3)0.23260 (8)0.0328 (4)
C30.83238 (11)0.3674 (3)0.21341 (9)0.0328 (4)
C40.93307 (13)0.1154 (3)0.23585 (10)0.0418 (5)
H40.97710.06350.26270.050*
C50.91455 (13)0.0006 (3)0.18141 (10)0.0401 (5)
H50.94460.12740.17200.048*
C60.85181 (12)0.0739 (3)0.14075 (9)0.0376 (5)
C70.81112 (11)0.2637 (3)0.15755 (9)0.0378 (5)
H70.76850.32240.13050.045*
C80.82828 (15)0.0466 (4)0.08138 (11)0.0510 (6)
H8A0.79100.16720.08980.077*
H8B0.87720.10660.06420.077*
H8C0.80120.05560.05150.077*
Cl10.50499 (4)0.55130 (10)0.09961 (3)0.0569 (2)
Cl20.65296 (4)0.52518 (12)0.03495 (3)0.0617 (3)
Cl30.57200 (4)0.12697 (10)0.06982 (3)0.0582 (2)
C100.59461 (13)0.4006 (3)0.09061 (10)0.0416 (5)
H100.62750.39990.13120.050*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0398 (9)0.0332 (9)0.0377 (9)0.0008 (7)0.0045 (7)0.0041 (7)
N20.0429 (9)0.0351 (9)0.0405 (9)0.0005 (7)0.0053 (7)0.0032 (7)
C10.0404 (10)0.0333 (10)0.0385 (10)0.0002 (8)0.0035 (8)0.0027 (8)
C20.0356 (10)0.0294 (10)0.0340 (10)0.0039 (8)0.0075 (7)0.0008 (8)
C30.0343 (9)0.0290 (9)0.0358 (10)0.0042 (7)0.0090 (7)0.0001 (7)
C40.0467 (11)0.0374 (11)0.0417 (11)0.0052 (9)0.0054 (8)0.0004 (8)
C50.0460 (11)0.0326 (10)0.0433 (11)0.0022 (8)0.0140 (9)0.0003 (8)
C60.0424 (10)0.0343 (10)0.0377 (10)0.0038 (8)0.0136 (8)0.0047 (8)
C70.0388 (10)0.0381 (11)0.0372 (10)0.0011 (8)0.0077 (8)0.0025 (8)
C80.0578 (13)0.0499 (13)0.0460 (12)0.0046 (10)0.0076 (10)0.0152 (10)
Cl10.0557 (4)0.0538 (4)0.0613 (4)0.0130 (3)0.0040 (3)0.0024 (3)
Cl20.0589 (4)0.0759 (5)0.0507 (4)0.0204 (3)0.0069 (3)0.0140 (3)
Cl30.0758 (5)0.0417 (4)0.0594 (4)0.0037 (3)0.0207 (3)0.0062 (2)
C100.0449 (11)0.0426 (11)0.0376 (11)0.0012 (9)0.0041 (8)0.0024 (9)
Geometric parameters (Å, º) top
N1—C11.329 (3)C5—H50.9500
N1—C21.340 (3)C6—C71.393 (3)
N2—C41.339 (3)C6—C81.504 (3)
N2—C31.346 (3)C7—H70.9500
C1—C2i1.391 (3)C8—H8A0.9800
C1—H10.9500C8—H8B0.9800
C2—C1i1.391 (3)C8—H8C0.9800
C2—C31.484 (3)Cl1—C101.757 (2)
C3—C71.385 (3)Cl2—C101.760 (2)
C4—C51.383 (3)Cl3—C101.753 (2)
C4—H40.9500C10—H101.0000
C5—C61.383 (3)
C1—N1—C2116.90 (17)C5—C6—C8121.56 (19)
C4—N2—C3116.44 (17)C7—C6—C8121.58 (19)
N1—C1—C2i122.74 (18)C3—C7—C6120.36 (18)
N1—C1—H1118.6C3—C7—H7119.8
C2i—C1—H1118.6C6—C7—H7119.8
N1—C2—C1i120.36 (17)C6—C8—H8A109.5
N1—C2—C3117.77 (16)C6—C8—H8B109.5
C1i—C2—C3121.87 (17)H8A—C8—H8B109.5
N2—C3—C7122.68 (17)C6—C8—H8C109.5
N2—C3—C2116.19 (16)H8A—C8—H8C109.5
C7—C3—C2121.13 (17)H8B—C8—H8C109.5
N2—C4—C5124.3 (2)Cl3—C10—Cl1110.88 (12)
N2—C4—H4117.9Cl3—C10—Cl2110.37 (12)
C5—C4—H4117.9Cl1—C10—Cl2110.64 (12)
C6—C5—C4119.35 (19)Cl3—C10—H10108.3
C6—C5—H5120.3Cl1—C10—H10108.3
C4—C5—H5120.3Cl2—C10—H10108.3
C5—C6—C7116.86 (18)
C2—N1—C1—C2i0.8 (3)C3—N2—C4—C51.7 (3)
C1—N1—C2—C1i0.7 (3)N2—C4—C5—C61.2 (3)
C1—N1—C2—C3179.12 (16)C4—C5—C6—C70.6 (3)
C4—N2—C3—C70.5 (3)C4—C5—C6—C8179.05 (19)
C4—N2—C3—C2179.40 (16)N2—C3—C7—C61.2 (3)
N1—C2—C3—N2174.82 (17)C2—C3—C7—C6178.94 (16)
C1i—C2—C3—N25.3 (3)C5—C6—C7—C31.7 (3)
N1—C2—C3—C75.3 (3)C8—C6—C7—C3177.96 (19)
C1i—C2—C3—C7174.56 (18)
Symmetry code: (i) x+3/2, y+3/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C10—H10···N11.002.503.335 (3)141
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C10—H10···N11.002.503.335 (3)141
 

Footnotes

This work is part of the PhD thesis (Neuchâtel, 2008) of LS.

Acknowledgements

This work was supported by the Swiss National Science Foundation and the University of Neuchâtel.

References

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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 70| Part 9| September 2014| Pages o893-o894
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