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

Rathore, R.S.; Narasimhamurthy, T.; Ragavan, R.V.; Vijayakumar, V.; Sarveswari, S.

doi:10.1107/S160053681102808X

organic compounds

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ISSN: 2056-9890

Volume 67| Part 8| August 2011| Page o2129

doi:10.1107/S160053681102808X

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

R. S. Rathore,^a ^* T. Narasimhamurthy,^b R. Venkat Ragavan,^c V. Vijayakumar ^c and S. Sarveswari ^c

^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 , 2010 ) and references therein. For related salt-bridge-mediated sheet structures, see: Shylaja et al. (2008 ).

Experimental

Crystal data

C₆H₁₀N₂O
M_r = 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 ) T_min = 0.64, T_max = 0.83
12120 measured reflections
1332 independent reflections
961 reflections with I > 2σ(I)
R_int = 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
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	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 ); cell refinement: SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus; 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 and PLATON (Spek, 2009).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053681102808X/su2287sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053681102808X/su2287Isup2.hkl

Supporting information file. DOI: 10.1107/S160053681102808X/su2287Isup3.cml

checkCIF report

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.

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

	Fig. 1. A view of the molecular structure of the title molecule, with labelling scheme and displacement ellipsoids drawn at the 30% probability level.
	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

C₆H₁₀N₂O	F(000) = 272
M_r = 126.16	D_x = 1.227 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3015 reflections
a = 9.1299 (15) Å	θ = 2.4–22.9°
b = 7.1600 (11) Å	µ = 0.09 mm⁻¹
c = 11.374 (2) Å	T = 296 K
β = 113.232 (9)°	Plate, colourless
V = 683.2 (2) Å³	0.21 × 0.19 × 0.11 mm
Z = 4

Data collection top

Bruker APEXII CCD diffractometer	1332 independent reflections
Radiation source: fine-focus sealed tube	961 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.034
ϕ and ω scans	θ_max = 26.0°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −11→11
T_min = 0.64, T_max = 0.83	k = −8→8
12120 measured reflections	l = −13→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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.136	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ²(F_o²) + (0.0674P)² + 0.2195P] where P = (F_o² + 2F_c²)/3
1332 reflections	(Δ/σ)_max < 0.001
92 parameters	Δρ_max = 0.17 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₆H₁₀N₂O	V = 683.2 (2) Å³
M_r = 126.16	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 9.1299 (15) Å	µ = 0.09 mm⁻¹
b = 7.1600 (11) Å	T = 296 K
c = 11.374 (2) Å	0.21 × 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)
T_min = 0.64, T_max = 0.83	R_int = 0.034
12120 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.049	0 restraints
wR(F²) = 0.136	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	Δρ_max = 0.17 e Å⁻³
1332 reflections	Δρ_min = −0.21 e Å⁻³
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

	x	y	z	U_iso*/U_eq
N1	0.0756 (2)	0.1929 (2)	0.58699 (14)	0.0427 (5)
H1	0.029 (3)	0.087 (3)	0.601 (2)	0.051 (6)*
N2	0.1373 (2)	0.3275 (2)	0.67795 (15)	0.0462 (5)
H2	0.116 (3)	0.326 (3)	0.754 (2)	0.062 (6)*
O5	0.07244 (17)	0.12652 (19)	0.38750 (11)	0.0489 (4)
C3	0.2107 (2)	0.4552 (3)	0.63369 (17)	0.0402 (5)
C3A	0.2903 (3)	0.6189 (3)	0.7141 (2)	0.0573 (6)
H3A1	0.2994	0.7177	0.6591	0.069*
H3A2	0.2238	0.6648	0.7566	0.069*
C3B	0.4512 (4)	0.5766 (4)	0.8123 (3)	0.1014 (12)
H3B1	0.4424	0.4859	0.8714	0.152*
H3B2	0.4982	0.6889	0.8577	0.152*
H3B3	0.5171	0.5277	0.7714	0.152*
C4	0.1999 (2)	0.4015 (2)	0.51474 (17)	0.0367 (5)
C4A	0.2643 (3)	0.4995 (3)	0.4291 (2)	0.0544 (6)
H41	0.3131	0.6149	0.4681	0.082*
H42	0.1789	0.5248	0.3482	0.082*
H43	0.3422	0.4216	0.4162	0.082*
C5	0.1135 (2)	0.2330 (3)	0.48611 (16)	0.0359 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0661 (11)	0.0389 (9)	0.0308 (8)	−0.0145 (8)	0.0275 (8)	−0.0061 (7)
N2	0.0698 (12)	0.0444 (10)	0.0313 (9)	−0.0109 (8)	0.0275 (8)	−0.0098 (7)
O5	0.0759 (10)	0.0484 (8)	0.0304 (7)	−0.0197 (7)	0.0295 (7)	−0.0092 (6)
C3	0.0470 (11)	0.0362 (10)	0.0369 (10)	−0.0008 (8)	0.0162 (9)	−0.0008 (8)
C3A	0.0725 (15)	0.0467 (12)	0.0519 (13)	−0.0103 (11)	0.0237 (12)	−0.0149 (10)
C3B	0.084 (2)	0.082 (2)	0.097 (2)	−0.0121 (16)	−0.0077 (17)	−0.0341 (18)
C4	0.0428 (10)	0.0361 (10)	0.0322 (9)	−0.0018 (8)	0.0159 (8)	0.0016 (8)
C4A	0.0632 (14)	0.0566 (13)	0.0485 (12)	−0.0143 (11)	0.0274 (11)	0.0035 (10)
C5	0.0455 (10)	0.0378 (10)	0.0266 (9)	−0.0018 (8)	0.0165 (8)	0.0003 (8)

Geometric parameters (Å, º) top

N1—C5	1.354 (2)	C3A—H3A2	0.9700
N1—N2	1.363 (2)	C3B—H3B1	0.9600
N1—H1	0.92 (2)	C3B—H3B2	0.9600
N2—C3	1.343 (3)	C3B—H3B3	0.9600
N2—H2	0.95 (3)	C4—C5	1.408 (3)
O5—C5	1.284 (2)	C4—C4A	1.495 (3)
C3—C4	1.372 (3)	C4A—H41	0.9600
C3—C3A	1.488 (3)	C4A—H42	0.9600
C3A—C3B	1.484 (4)	C4A—H43	0.9600
C3A—H3A1	0.9700

C5—N1—N2	109.01 (16)	H3B1—C3B—H3B2	109.5
C5—N1—H1	128.2 (13)	C3A—C3B—H3B3	109.5
N2—N1—H1	122.3 (13)	H3B1—C3B—H3B3	109.5
C3—N2—N1	108.38 (16)	H3B2—C3B—H3B3	109.5
C3—N2—H2	130.8 (14)	C3—C4—C5	106.50 (16)
N1—N2—H2	120.5 (14)	C3—C4—C4A	128.08 (17)
N2—C3—C4	109.04 (16)	C5—C4—C4A	125.42 (17)
N2—C3—C3A	120.03 (18)	C4—C4A—H41	109.5
C4—C3—C3A	130.90 (18)	C4—C4A—H42	109.5
C3B—C3A—C3	113.6 (2)	H41—C4A—H42	109.5
C3B—C3A—H3A1	108.8	C4—C4A—H43	109.5
C3—C3A—H3A1	108.8	H41—C4A—H43	109.5
C3B—C3A—H3A2	108.8	H42—C4A—H43	109.5
C3—C3A—H3A2	108.8	O5—C5—N1	122.03 (16)
H3A1—C3A—H3A2	107.7	O5—C5—C4	130.92 (17)
C3A—C3B—H3B1	109.5	N1—C5—C4	107.05 (15)
C3A—C3B—H3B2	109.5

C5—N1—N2—C3	1.6 (2)	C3A—C3—C4—C4A	−1.7 (3)
N1—N2—C3—C4	−1.4 (2)	N2—N1—C5—O5	178.68 (17)
N1—N2—C3—C3A	−179.69 (17)	N2—N1—C5—C4	−1.2 (2)
N2—C3—C3A—C3B	80.6 (3)	C3—C4—C5—O5	−179.5 (2)
C4—C3—C3A—C3B	−97.3 (3)	C4A—C4—C5—O5	0.9 (3)
N2—C3—C4—C5	0.7 (2)	C3—C4—C5—N1	0.3 (2)
C3A—C3—C4—C5	178.7 (2)	C4A—C4—C5—N1	−179.25 (18)
N2—C3—C4—C4A	−179.80 (19)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	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+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula	C₆H₁₀N₂O
M_r	126.16
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	9.1299 (15), 7.1600 (11), 11.374 (2)
β (°)	113.232 (9)
V (Å³)	683.2 (2)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.21 × 0.19 × 0.11

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2001)
T_min, T_max	0.64, 0.83
No. of measured, independent and observed [I > 2σ(I)] reflections	12120, 1332, 961
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.136, 1.03
No. of reflections	1332
No. of parameters	92
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	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···A	D—H	H···A	D···A	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+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.

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