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ISSN: 2056-9890

3-Ethyl-4-methyl-1H-pyrazol-2-ium-5-olate

aBioinformatics Infrastructure Facility, School of Life Science, University of Hyderabad, Hyderabad 500 046, India, bMaterials Research Center, Indian Institute of Science, Bangalore 560 012, India, and cOrganic Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632 014, India
*Correspondence e-mail: rsrsl@uohyd.ernet.in

(Received 24 June 2011; accepted 13 July 2011; online 23 July 2011)

The title compound, C6H10N2O, is a zwitterionic pyrazole derivative. The crystal packing is predominantly governed by a three-center iminium–amine N+—H⋯O⋯H—N inter­action, leading to an undulating sheet-like structure lying parallel to (100).

Related literature

For related structures and the preparation of similar compounds, see: Ragavan et al. (2009[Ragavan, R. V., Vijayakumar, V. & Kumari, N. S. (2009). Eur. J. Med. Chem. 44, 3852-3857.], 2010[Ragavan, R. V., Vijayakumar, V. & Kumari, N. S. (2010). Eur. J. Med. Chem. 45, 1173-1180.]) and references therein. For related salt-bridge-mediated sheet structures, see: Shylaja et al. (2008[Shylaja, S., Mahendra, K. N., Varma, K. B. R., Narasimhamurthy, T. & Rathore, R. S. (2008). Acta Cryst. C64, o361-o363.]).

[Scheme 1]

Experimental

Crystal data
  • C6H10N2O

  • Mr = 126.16

  • Monoclinic, P 21 /c

  • a = 9.1299 (15) Å

  • b = 7.1600 (11) Å

  • c = 11.374 (2) Å

  • β = 113.232 (9)°

  • V = 683.2 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 296 K

  • 0.21 × 0.19 × 0.11 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2001[Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.64, Tmax = 0.83

  • 12120 measured reflections

  • 1332 independent reflections

  • 961 reflections with I > 2σ(I)

  • Rint = 0.034

Refinement
  • R[F2 > 2σ(F2)] = 0.049

  • wR(F2) = 0.136

  • S = 1.03

  • 1332 reflections

  • 92 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.17 e Å−3

  • Δρmin = −0.21 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯O5i 0.91 (2) 1.82 (2) 2.730 (2) 175 (2)
N2—H2⋯O5ii 0.96 (2) 1.75 (2) 2.693 (2) 168 (2)
Symmetry codes: (i) -x, -y, -z+1; (ii) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2 and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 2007[Bruker (2007). APEX2 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: ORTEP-3 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

As a part of our interest in antimicrobial compounds, we have synthesized the title pyrazole derivative using the procedure described earlier by (Ragavan et al., 2009, and references therein; 2010, and references therein).

The molecular structure of the title molecule is shown in Fig 1. The methyl atom (C3B) of the 3-ethyl substituent lies out of the mean plane of the pyrazole moiety (N1,N2,C3-C5) by 1.366 (4) Å.

The crystal packing is a fine balance of strong N—H···O hydrogen bonds (Table 1) and salt bridges, which normally tend to promote the formation of a planar structure and compact packing (Shylaja et al., 2008). In the title compound all the hydrogen bonding donors, iminium N+H (N1) and amine NH (N2), and the O-(O1) acceptor, are in the plane of the pyrazole moiety, which would normally yield a planar hydrogen-bonded structure. However, in order to accommodate the out-of-plane methyl group, (C3B), an undulating hydrogen bonded sheet-like structure, lieing paralallel to (100), is formed (Fig. 2).

Related literature top

For related structures and the preparation of similar compounds, see: Ragavan et al. (2009, 2010) and references therein. For related salt-bridge-mediated sheet structures, see: Shylaja et al. (2008).

Experimental top

The title compound was synthesized using the method described earlier by (Ragavan et al., 2009, 2010). It was crystallized using an ethanol-chloroform (1:1) mixture. Yield, 74%; m.p. 779-780 K.

Refinement top

The NH atoms were located in a difference Fourier map and were freely refined: N2—H2 = 0.92 (2) Å and N1+—H1 = 0.95 (3) Å. The methylene and methyl hydrogen atoms were placed in calculated positions and refined as riding atoms: C-H = 0.97 and 0.96 Å, for CH and CH3 H-atoms, respectively, with Uiso(H) = k × Ueq(C,) where k = 1.5 for CH3 H-atoms and 1.2 for the CH H-atoms.

Computing details top

Data collection: APEX2 (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: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. A view of the molecular structure of the title molecule, with labelling scheme and displacement ellipsoids drawn at the 30% probability level.
[Figure 2] Fig. 2. A view of the N—H···O hydrogen bonded (dashed cyan lines) sheet structure in the crystal structure of the title compound (see Table 1 for details).
3-Ethyl-4-methyl-1H-pyrazol-2-ium-5-olate top
Crystal data top
C6H10N2OF(000) = 272
Mr = 126.16Dx = 1.227 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3015 reflections
a = 9.1299 (15) Åθ = 2.4–22.9°
b = 7.1600 (11) ŵ = 0.09 mm1
c = 11.374 (2) ÅT = 296 K
β = 113.232 (9)°Plate, colourless
V = 683.2 (2) Å30.21 × 0.19 × 0.11 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer
1332 independent reflections
Radiation source: fine-focus sealed tube961 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.034
ϕ and ω scansθmax = 26.0°, θmin = 2.4°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
h = 1111
Tmin = 0.64, Tmax = 0.83k = 88
12120 measured reflectionsl = 1313
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) = 0.136H atoms treated by a mixture of independent and constrained refinement
S = 1.03 w = 1/[σ2(Fo2) + (0.0674P)2 + 0.2195P]
where P = (Fo2 + 2Fc2)/3
1332 reflections(Δ/σ)max < 0.001
92 parametersΔρmax = 0.17 e Å3
0 restraintsΔρmin = 0.21 e Å3
Crystal data top
C6H10N2OV = 683.2 (2) Å3
Mr = 126.16Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.1299 (15) ŵ = 0.09 mm1
b = 7.1600 (11) ÅT = 296 K
c = 11.374 (2) Å0.21 × 0.19 × 0.11 mm
β = 113.232 (9)°
Data collection top
Bruker APEXII CCD
diffractometer
1332 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
961 reflections with I > 2σ(I)
Tmin = 0.64, Tmax = 0.83Rint = 0.034
12120 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0490 restraints
wR(F2) = 0.136H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.17 e Å3
1332 reflectionsΔρmin = 0.21 e Å3
92 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
xyzUiso*/Ueq
N10.0756 (2)0.1929 (2)0.58699 (14)0.0427 (5)
H10.029 (3)0.087 (3)0.601 (2)0.051 (6)*
N20.1373 (2)0.3275 (2)0.67795 (15)0.0462 (5)
H20.116 (3)0.326 (3)0.754 (2)0.062 (6)*
O50.07244 (17)0.12652 (19)0.38750 (11)0.0489 (4)
C30.2107 (2)0.4552 (3)0.63369 (17)0.0402 (5)
C3A0.2903 (3)0.6189 (3)0.7141 (2)0.0573 (6)
H3A10.29940.71770.65910.069*
H3A20.22380.66480.75660.069*
C3B0.4512 (4)0.5766 (4)0.8123 (3)0.1014 (12)
H3B10.44240.48590.87140.152*
H3B20.49820.68890.85770.152*
H3B30.51710.52770.77140.152*
C40.1999 (2)0.4015 (2)0.51474 (17)0.0367 (5)
C4A0.2643 (3)0.4995 (3)0.4291 (2)0.0544 (6)
H410.31310.61490.46810.082*
H420.17890.52480.34820.082*
H430.34220.42160.41620.082*
C50.1135 (2)0.2330 (3)0.48611 (16)0.0359 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0661 (11)0.0389 (9)0.0308 (8)0.0145 (8)0.0275 (8)0.0061 (7)
N20.0698 (12)0.0444 (10)0.0313 (9)0.0109 (8)0.0275 (8)0.0098 (7)
O50.0759 (10)0.0484 (8)0.0304 (7)0.0197 (7)0.0295 (7)0.0092 (6)
C30.0470 (11)0.0362 (10)0.0369 (10)0.0008 (8)0.0162 (9)0.0008 (8)
C3A0.0725 (15)0.0467 (12)0.0519 (13)0.0103 (11)0.0237 (12)0.0149 (10)
C3B0.084 (2)0.082 (2)0.097 (2)0.0121 (16)0.0077 (17)0.0341 (18)
C40.0428 (10)0.0361 (10)0.0322 (9)0.0018 (8)0.0159 (8)0.0016 (8)
C4A0.0632 (14)0.0566 (13)0.0485 (12)0.0143 (11)0.0274 (11)0.0035 (10)
C50.0455 (10)0.0378 (10)0.0266 (9)0.0018 (8)0.0165 (8)0.0003 (8)
Geometric parameters (Å, º) top
N1—C51.354 (2)C3A—H3A20.9700
N1—N21.363 (2)C3B—H3B10.9600
N1—H10.92 (2)C3B—H3B20.9600
N2—C31.343 (3)C3B—H3B30.9600
N2—H20.95 (3)C4—C51.408 (3)
O5—C51.284 (2)C4—C4A1.495 (3)
C3—C41.372 (3)C4A—H410.9600
C3—C3A1.488 (3)C4A—H420.9600
C3A—C3B1.484 (4)C4A—H430.9600
C3A—H3A10.9700
C5—N1—N2109.01 (16)H3B1—C3B—H3B2109.5
C5—N1—H1128.2 (13)C3A—C3B—H3B3109.5
N2—N1—H1122.3 (13)H3B1—C3B—H3B3109.5
C3—N2—N1108.38 (16)H3B2—C3B—H3B3109.5
C3—N2—H2130.8 (14)C3—C4—C5106.50 (16)
N1—N2—H2120.5 (14)C3—C4—C4A128.08 (17)
N2—C3—C4109.04 (16)C5—C4—C4A125.42 (17)
N2—C3—C3A120.03 (18)C4—C4A—H41109.5
C4—C3—C3A130.90 (18)C4—C4A—H42109.5
C3B—C3A—C3113.6 (2)H41—C4A—H42109.5
C3B—C3A—H3A1108.8C4—C4A—H43109.5
C3—C3A—H3A1108.8H41—C4A—H43109.5
C3B—C3A—H3A2108.8H42—C4A—H43109.5
C3—C3A—H3A2108.8O5—C5—N1122.03 (16)
H3A1—C3A—H3A2107.7O5—C5—C4130.92 (17)
C3A—C3B—H3B1109.5N1—C5—C4107.05 (15)
C3A—C3B—H3B2109.5
C5—N1—N2—C31.6 (2)C3A—C3—C4—C4A1.7 (3)
N1—N2—C3—C41.4 (2)N2—N1—C5—O5178.68 (17)
N1—N2—C3—C3A179.69 (17)N2—N1—C5—C41.2 (2)
N2—C3—C3A—C3B80.6 (3)C3—C4—C5—O5179.5 (2)
C4—C3—C3A—C3B97.3 (3)C4A—C4—C5—O50.9 (3)
N2—C3—C4—C50.7 (2)C3—C4—C5—N10.3 (2)
C3A—C3—C4—C5178.7 (2)C4A—C4—C5—N1179.25 (18)
N2—C3—C4—C4A179.80 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O5i0.91 (2)1.82 (2)2.730 (2)175 (2)
N2—H2···O5ii0.96 (2)1.75 (2)2.693 (2)168 (2)
Symmetry codes: (i) x, y, z+1; (ii) x, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC6H10N2O
Mr126.16
Crystal system, space groupMonoclinic, P21/c
Temperature (K)296
a, b, c (Å)9.1299 (15), 7.1600 (11), 11.374 (2)
β (°) 113.232 (9)
V3)683.2 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.21 × 0.19 × 0.11
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2001)
Tmin, Tmax0.64, 0.83
No. of measured, independent and
observed [I > 2σ(I)] reflections
12120, 1332, 961
Rint0.034
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.136, 1.03
No. of reflections1332
No. of parameters92
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.17, 0.21

Computer programs: APEX2 (Bruker, 2007), SAINT-Plus (Bruker, 2007), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O5i0.91 (2)1.82 (2)2.730 (2)175 (2)
N2—H2···O5ii0.96 (2)1.75 (2)2.693 (2)168 (2)
Symmetry codes: (i) x, y, z+1; (ii) x, y+1/2, z+1/2.
 

Acknowledgements

We acknowledge the CCD facility, set up under the IRHPA–DST program at the IISc, Bangalore. VV thanks the DST for financial assistance under the Fast-Track young scientist scheme, and RSR acknowledges the CSIR for funding under the scientist's pool scheme.

References

First citationBruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBruker (2007). APEX2 and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationRagavan, R. V., Vijayakumar, V. & Kumari, N. S. (2009). Eur. J. Med. Chem. 44, 3852–3857.  PubMed CAS Google Scholar
First citationRagavan, R. V., Vijayakumar, V. & Kumari, N. S. (2010). Eur. J. Med. Chem. 45, 1173–1180.  Web of Science CrossRef CAS PubMed Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationShylaja, S., Mahendra, K. N., Varma, K. B. R., Narasimhamurthy, T. & Rathore, R. S. (2008). Acta Cryst. C64, o361–o363.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148-155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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ISSN: 2056-9890
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