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

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ISSN: 2056-9890

2,5-Di­methyl­pyrazine 1,4-dioxide

aAllegheny College, Chemistry Department, 520 North Main St., Meadville, PA 16335, USA
*Correspondence e-mail: jknaust@allegheny.edu

(Received 4 November 2009; accepted 5 November 2009; online 11 November 2009)

The title compound, C6H8N2O2, was prepared from 2,5-dimethyl­pyrazine, acetic acid, and hydrogen peroxide. The 2,5-dimethyl­pyrazine 1,4-dioxide mol­ecule is located on an inversion center. ππ inter­actions between neighboring 2,5-dimethyl­pyrazine 1,4-dioxide mol­ecules are observed with an inter­planar distance of 3.191 Å. Each 2,5-dimethyl­pyrazine 1,4-dioxide mol­ecule is linked to four neighboring N-oxide mol­ecules through C—H⋯O hydrogen-bonding inter­actions, forming two-dimensional layers.

Related literature

For the synthesis of 2,2′-bipyridine N,N′-dioxide, see: Simpson et al. (1963[Simpson, P. G., Vinciguerra, A. & Quagliano, J. V. (1963). Inorg. Chem. 2, 282-286.]). For the synthesis of lanthanide coordination networks with pyrazine N,N′-dioxide, see: Cardoso et al. (2001[Cardoso, M. C. C., Zinner, L. B., Zukerman-Scheptor, J., Araújo Melo, D. M. & Vincentini, G. J. (2001). J. Alloys Compd, 323-324, 22-25.]); Sun et al. (2004[Sun, H. L., Gao, S., Ma, B. Q., Chang, F. & Fu, W. F. (2004). Microporous Mesoporous Mater. 73 89-95.]). For the use of 2,5-dimethyl­pyrazine 1,4-dioxide in the synthesis of transition metal coordination networks, see: Shi, Sun et al. (2006[Shi, J. M., Sun, Y. M., Zhang, X., Yi, L., Cheng, P. & Liu, L. D. (2006). J. Phys. Chem. A, 110, 7677-7681.]); Shi, Zhang et al. (2006[Shi, J. M., Zhang, X., Wu, C. J. & Liu, L. D. (2006). Pol. J. Chem. 80, 2063-2068.]); Shi et al. (2007[Shi, J. M., Zhang, X., Xu, H. Y., Wu, C. W. & Liu, L. D. (2007). J. Coord. Chem. 60, 647-654.]); Sun, Gao et al. (2005[Sun, H. L., Gao, S., Ma, B. Q., Su, G. & Batten, S. R. (2005). Cryst. Growth Des. 5, 269-277.]); Sun, Wang et al. (2005[Sun, H. L., Wang, Z. M. & Gao, S. (2005). Inorg. Chem. 44, 2169-2176.]). For related structures, see: Näther et al. (2002[Näther, C., Kowallik, P. & Jess, I. (2002). Acta Cryst. E58, o1253-o1254.]); Gratton & Knaust (2009[Gratton, J. L. & Knaust, J. M. (2009). Acta Cryst. E65, o3040.]).

[Scheme 1]

Experimental

Crystal data
  • C6H8N2O2

  • Mr = 140.14

  • Monoclinic, P 21 /c

  • a = 3.9971 (8) Å

  • b = 8.9176 (17) Å

  • c = 8.9249 (17) Å

  • β = 102.205 (3)°

  • V = 310.93 (10) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.12 mm−1

  • T = 173 K

  • 0.45 × 0.12 × 0.11 mm

Data collection
  • Bruker SMART APEX CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2001[Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.623, Tmax = 0.746

  • 2388 measured reflections

  • 965 independent reflections

  • 811 reflections with I > 2σ(I)

  • Rint = 0.023

Refinement
  • R[F2 > 2σ(F2)] = 0.049

  • wR(F2) = 0.144

  • S = 1.07

  • 965 reflections

  • 47 parameters

  • H-atom parameters constrained

  • Δρmax = 0.62 e Å−3

  • Δρmin = −0.34 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C1—H1C⋯O1i 0.98 2.41 3.3290 (15) 155
C3—H3⋯O1i 0.95 2.31 3.1863 (15) 153
Symmetry code: (i) [x+1, -y+{\script{1\over 2}}, z+{\script{1\over 2}}].

Data collection: SMART (Bruker, 2007[Bruker (2007). SMART and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 2007[Bruker (2007). SMART and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: X-SEED (Barbour, 2001[Barbour, L. J. (2001). J. Supramol. Chem. 1, 189-191.]); software used to prepare material for publication: X-SEED.

Supporting information


Comment top

The use of pyrazine N,N'-dioxide in the synthesis of lanthanide coordination networks has been of recent interest (Cardoso et al. (2001), and Sun et al. (2004)). Shi, Sun et al. (2006), Shi, Zhang et al. (2006), Shi et al. (2007), Sun, Gao et al. (2005), and Sun, Wang et al. (2005) recently reported the use 2,5-dimethylpyrazine 1,4-dioxide in the synthesis of a transition metal coordination networks. The title compound was prepared using the reaction conditions described by Simpson et al. (1963) to prepare 2,2'-bipyridine N,N'-dioxide.

The asymmetric unit of the title compound contains half of a 2,5-dimethylpyrazine 1,4-dioxide molecule (Figure 1) and the N-oxide molecule lies on an inversion center. π-Cloud interactions between neighboring 2,5-dimethylpyrazine 1,4-dioxide molecules are observed with an interplanar distance of 3.191 Å (Figure 2); there is a slippage of 2.408 Å such that N1iii on the neighboring N-oxide molecule lies directly over the centroid of the C3—N1i bond [symmetry codes: (i) -x + 1, -y, -z + 1; (iii) x + 1, y, z] (Figure 3). The title compound forms eight C—H···O hydrogen bonds with four neighboring N-oxide molecules, and these hydrogen bonding interactions result in the formation of two-dimensional layers (Figure 5); whereas in the related structures of 2-methylpyrazine 1,4-dioxide and pyrazine N,N'-dioxide, the N-oxide molecules form hydrogen bonded ribbons and a three-dimensional network, respectively (Gratton et al. (2009), Näther et al. (2002)). A packing diagram of the title compound is given in Figure 5.

Related literature top

For the synthesis of 2,2'-bipyridine N,N'-dioxide, see: Simpson et al. (1963). For the synthesis of lanthanide coordination networks with pyrazine N,N'-dioxide, see: Cardoso et al. (2001); Sun et al. (2004). For the use of 2,5-dimethylpyrazine 1,4-dioxide in the synthesis of transition metal coordination networks, see: Shi, Sun et al. (2006); Shi, Zhang et al. (2006); Shi et al. (2007); Sun, Gao et al. (2005); Sun, Wang et al. (2005). For related structures, see: Näther et al. (2002); Gratton et al. (2009).

Experimental top

2,5-Dimethylpyrazine (6.99 ml, 64.0 mmol), acetic acid (75 ml), and 30% hydrogen peroxide (13 ml) were heated at 343–353 K for 3 h. Additional hydrogen peroxide (9 ml) was added, and heating was continued. After an additional 19 h of heating the solution was cooled to room temperature. Crystals formed upon the addition of acetone (1L) and cooling to 273 K, and were recrystallized from hot water by addition of excess acetone and cooling to 273 K.

Refinement top

All H atoms were positioned geometrically and refined using a riding model with C—H = 0.95–0.99 Å and with Uiso(H) = 1.2 (1.5 for methyl groups) times Ueq(C).

Computing details top

Data collection: SMART (Bruker, 2007); cell refinement: SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: X-SEED (Barbour, 2001).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with atom labels and 50% probability displacement ellipsoids for non-H atoms. Atoms not labeled are generated by the symmetry operator (i) -x + 1,-y, -z + 1.
[Figure 2] Fig. 2. Space filling representation of the π-cloud interactions between neighboring 2,5-dimethylpyrazine 1,4-dioxide molecules.
[Figure 3] Fig. 3. Ball and stick representation of the π-cloud interactions between neighboring 2,5-diethylpyrazine 1,4-dioxide molecules. symmetry codes: (i) -x + 1, -y, -z + 1; (iii) x + 1, y, z; (iv) -x + 2, -y, -z + 1
[Figure 4] Fig. 4. C—H···O hydrogen bonding interactions between neighboring 2,5-dimethylpyrazine 1,4-dioxide molecules. Hydrogen bonds are shown as dashed lines. Symmetry code: (ii) x + 1, -y + 1/2, z +1 /2.
[Figure 5] Fig. 5. Packing of the title compound viewed down the b axis. Hydrogen bonds are shown as dashed red lines, and π-cloud interactions are shown as dashed blue lines.
2,5-Dimethylpyrazine 1,4-dioxide top
Crystal data top
C6H8N2O2F(000) = 148
Mr = 140.14Dx = 1.497 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 958 reflections
a = 3.9971 (8) Åθ = 3.3–31.5°
b = 8.9176 (17) ŵ = 0.12 mm1
c = 8.9249 (17) ÅT = 173 K
β = 102.205 (3)°Rod, colorless
V = 310.93 (10) Å30.45 × 0.12 × 0.11 mm
Z = 2
Data collection top
Bruker SMART APEX CCD
diffractometer
965 independent reflections
Radiation source: fine-focus sealed tube811 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.023
ω scansθmax = 31.5°, θmin = 3.3°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
h = 55
Tmin = 0.623, Tmax = 0.746k = 129
2388 measured reflectionsl = 128
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.144H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0934P)2 + 0.0493P]
where P = (Fo2 + 2Fc2)/3
965 reflections(Δ/σ)max < 0.001
47 parametersΔρmax = 0.62 e Å3
0 restraintsΔρmin = 0.34 e Å3
Crystal data top
C6H8N2O2V = 310.93 (10) Å3
Mr = 140.14Z = 2
Monoclinic, P21/cMo Kα radiation
a = 3.9971 (8) ŵ = 0.12 mm1
b = 8.9176 (17) ÅT = 173 K
c = 8.9249 (17) Å0.45 × 0.12 × 0.11 mm
β = 102.205 (3)°
Data collection top
Bruker SMART APEX CCD
diffractometer
965 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
811 reflections with I > 2σ(I)
Tmin = 0.623, Tmax = 0.746Rint = 0.023
2388 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0490 restraints
wR(F2) = 0.144H-atom parameters constrained
S = 1.07Δρmax = 0.62 e Å3
965 reflectionsΔρmin = 0.34 e Å3
47 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.

Highest peak 0.62 at 0.4105 0.2353 0.4867 [0.74 A from C1] Deepest hole -0.34 at 0.1454 0.0185 0.3480 [0.59 A from N1]

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.0014 (2)0.11342 (10)0.28187 (10)0.0190 (3)
N10.2436 (2)0.05941 (11)0.38743 (11)0.0141 (3)
C10.3636 (3)0.31533 (12)0.48341 (15)0.0182 (3)
H1A0.12860.33380.49480.027*
H1B0.39100.35220.38320.027*
H1C0.52380.36800.56470.027*
C20.4355 (3)0.15172 (13)0.49468 (13)0.0145 (3)
C30.6882 (3)0.09028 (12)0.60638 (14)0.0146 (3)
H30.81940.15430.68160.017*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0183 (4)0.0186 (5)0.0151 (5)0.0029 (3)0.0081 (3)0.0031 (3)
N10.0137 (4)0.0150 (5)0.0112 (5)0.0004 (3)0.0028 (4)0.0019 (4)
C10.0204 (5)0.0122 (5)0.0191 (6)0.0012 (4)0.0022 (4)0.0010 (4)
C20.0155 (5)0.0136 (5)0.0130 (5)0.0012 (4)0.0002 (4)0.0002 (4)
C30.0157 (5)0.0134 (5)0.0126 (5)0.0006 (4)0.0012 (4)0.0001 (4)
Geometric parameters (Å, º) top
O1—N11.2996 (12)C1—H1B0.9800
N1—C3i1.3611 (14)C1—H1C0.9800
N1—C21.3681 (15)C2—C31.3744 (15)
C1—C21.4863 (15)C3—H30.9500
C1—H1A0.9800
O1—N1—C3i120.44 (10)H1B—C1—H1C109.5
O1—N1—C2120.62 (10)N1—C2—C3119.01 (10)
C3i—N1—C2118.94 (10)N1—C2—C1118.14 (10)
C2—C1—H1A109.5C3—C2—C1122.85 (10)
C2—C1—H1B109.5N1i—C3—C2122.05 (10)
H1A—C1—H1B109.5N1i—C3—H3119.0
C2—C1—H1C109.5C2—C3—H3119.0
H1A—C1—H1C109.5
Symmetry code: (i) x+1, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1C···O1ii0.982.413.3290 (15)155
C3—H3···O1ii0.952.313.1863 (15)153
Symmetry code: (ii) x+1, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC6H8N2O2
Mr140.14
Crystal system, space groupMonoclinic, P21/c
Temperature (K)173
a, b, c (Å)3.9971 (8), 8.9176 (17), 8.9249 (17)
β (°) 102.205 (3)
V3)310.93 (10)
Z2
Radiation typeMo Kα
µ (mm1)0.12
Crystal size (mm)0.45 × 0.12 × 0.11
Data collection
DiffractometerBruker SMART APEX CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2001)
Tmin, Tmax0.623, 0.746
No. of measured, independent and
observed [I > 2σ(I)] reflections
2388, 965, 811
Rint0.023
(sin θ/λ)max1)0.735
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.144, 1.07
No. of reflections965
No. of parameters47
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.62, 0.34

Computer programs: SMART (Bruker, 2007), SAINT-Plus (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1—H1C···O1i0.982.413.3290 (15)155.1
C3—H3···O1i0.952.313.1863 (15)153.1
Symmetry code: (i) x+1, y+1/2, z+1/2.
 

Acknowledgements

The authors are grateful to Allegheny College for providing funding in support of this research. The diffractometer was funded by the NSF (grant No. 0087210), the Ohio Board of Regents (grant No. CAP-491) and by Youngstown State University. The authors would also like to acknowledge the STaRBURSTT CyberInstrumentation Consortium for assistance with the crystallography.

References

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