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

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ISSN: 2056-9890

2-Amino-6-methyl­pyridinium 4-nitro­benzoate

aState Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, People's Republic of China
*Correspondence e-mail: yiqiaohu@126.com

(Received 17 January 2011; accepted 27 January 2011; online 5 February 2011)

In the crystal structure of the title salt, C6H9N2+·C7H4NO4, the cations and anions are linked by N—H⋯O hydrogen bonds, forming chains running parallel to the b axis.

Related literature

For background to ways of decreasing of bitterness in foods and medicines, see: Suzuki et al. (2002[Suzuki, H., Kajimoto, Y. & Kumagai, H. (2002). J. Agric. Food Chem. 50, 313-318.], 2004[Suzuki, H., Kato, K. & Kumagai, H. (2004). J. Agric. Food Chem. 52, 577-580.]); Hofmann (1999[Hofmann, T. (1999). J. Agric. Food Chem. 47, 4763-4768.]); Shaw et al. (1984[Shaw, P. E., Tatum, J. H. & Wilson, C. W. (1984). J. Agric. Food Chem. 32, 832-836.]). For bond-length data, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]). For related structures, see: Saminathan & Sivakumar (2007a[Saminathan, K. & Sivakumar, K. (2007a). Acta Cryst. E63, o236-o238.],b[Saminathan, K. & Sivakumar, K. (2007b). Acta Cryst. E63, o354-o356.]); Näther et al. (1997[Näther, C., Arad, C. & Bock, H. (1997). Acta Cryst. C53, 76-79.]); In et al. (1997[In, Y., Nagata, H., Doi, M., Ishida, T. & Wakahara, A. (1997). Acta Cryst. C53, 646-648.]); Harrison et al. (2007[Harrison, W. T. A., Ashok, M. A., Yathirajan, H. S. & Narayana Achar, B. (2007). Acta Cryst. E63, o3322.]); Soriano-García et al. (1990[Soriano-García, M., Schatz-Levine, M., Toscano, R. A. & Villena Iribe, R. (1990). Acta Cryst. C46, 1556-1558.]); You et al. (2007[You, Z.-L., Dai, W.-M. & Hu, Y.-Q. (2007). Acta Cryst. E63, o3735.]).

[Scheme 1]

Experimental

Crystal data
  • C6H9N2+·C7H4NO4

  • Mr = 275.26

  • Monoclinic, P 21

  • a = 8.0487 (11) Å

  • b = 6.7247 (9) Å

  • c = 12.7467 (17) Å

  • β = 101.802 (7)°

  • V = 675.33 (16) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 298 K

  • 0.20 × 0.20 × 0.18 mm

Data collection
  • Bruker SMART 1000 CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2001[Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.980, Tmax = 0.982

  • 4175 measured reflections

  • 1591 independent reflections

  • 1265 reflections with I > 2σ(I)

  • Rint = 0.026

Refinement
  • R[F2 > 2σ(F2)] = 0.039

  • wR(F2) = 0.105

  • S = 1.04

  • 1591 reflections

  • 191 parameters

  • 5 restraints

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

  • Δρmax = 0.12 e Å−3

  • Δρmin = −0.17 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯O4i 0.91 (2) 1.75 (3) 2.649 (3) 173 (2)
N2—H2A⋯O3ii 0.89 (2) 1.94 (2) 2.812 (3) 170 (2)
N2—H2B⋯O3i 0.89 (2) 1.95 (2) 2.838 (3) 176 (2)
Symmetry codes: (i) x, y-1, z; (ii) [-x+1, y-{\script{1\over 2}}, -z].

Data collection: SMART (Bruker, 2007[Bruker (2007). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Considerable attention has been recently paid to the decrease the bitterness of foods and medicines (Suzuki et al., 2002; Suzuki et al., 2004; Hofmann, 1999; Shaw et al., 1984). 4-Nitrobenzoic acid is a bitter compound so, in order to investigate the influence of hydrogen bonds on its bitterness, the title compound was synthesized and its crystal structure is reported herein.

The asymmetric unit of the title salt consists of a 4-nitrobenzoate anion and a protonated 6-methyl-2-aminopyridinium cation (Fig. 1). The H atom of 4-nitrobenzoic acid is transferred to the N1 atom of 6-methyl-2-aminopyridine. All the bond lengths are within normal ranges (Allen et al., 1987) and comparable with the values observed in similar compounds (Saminathan & Sivakumar, 2007a,b; Näther et al., 1997; In et al., 1997; Harrison et al., 2007; Soriano-García et al., 1990; You et al., 2007). The C1—C6 benzene ring forms dihedral angles of 2.7 (2) and 0.2 (2)° with O1/N3/O2 and O3/C7/O4 planes, respectively. In the crystal structure (Fig. 2), intermolecular N—H···O hydrogen bonds (Table 1) link cations and anions into X-chains parallel to the b axis.

Related literature top

For background to ways of decreasing of bitterness in foods and medicines, see: Suzuki et al. (2002, 2004); Hofmann (1999); Shaw et al. (1984). For bond-length data, see: Allen et al. (1987). For related structures, see: Saminathan & Sivakumar (2007a,b); Näther et al. (1997); In et al. (1997); Harrison et al. (2007); Soriano-García et al. (1990); You et al. (2007).

Experimental top

All the reagents used were of commercially grade and without further purification. 4-Nitrobenzoic acid (0.1 mmol, 16.7 mg) and 6-methyl-2-aminopyridine (0.1 mmol, 10.8 mg) were dissolved in MeOH/H2O (10 ml, 1:1 v/v). The mixture was stirred at room temperature for 30 min to give a clear colourless solution. After keeping the solution in air for 20 days, colorless block-shaped crystals were formed on slow evaporation of the solvents.

Refinement top

The amino H atoms were located in a difference Fourier map and refined isotropically, with the N—H and H···H distances restrained to 0.90 (1) and 1.45 (2) Å, respectively, and with Uiso(H) set to 0.08 Å2. All other H atoms were placed in idealized positions and constrained to ride on their parent atoms with C—H distances of 0.93–0.96 Å, and with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C) for methyl H atoms. In the absence of significant anomalous dispersion effects, Friedel pairs were averaged.

Computing details top

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

Figures top
[Figure 1] Fig. 1. The structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme.
[Figure 2] Fig. 2. Crystal packing of the title compound, viewed along the b axis. Intermolecular hydrogen bonds are shown as dashed lines.
2-Amino-6-methylpyridinium 4-nitrobenzoate top
Crystal data top
C6H9N2+·C7H4NO4F(000) = 288
Mr = 275.26Dx = 1.354 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 1260 reflections
a = 8.0487 (11) Åθ = 2.5–24.5°
b = 6.7247 (9) ŵ = 0.10 mm1
c = 12.7467 (17) ÅT = 298 K
β = 101.802 (7)°Block, colourless
V = 675.33 (16) Å30.20 × 0.20 × 0.18 mm
Z = 2
Data collection top
Bruker SMART 1000 CCD area-detector
diffractometer
1591 independent reflections
Radiation source: fine-focus sealed tube1265 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
ω scansθmax = 27.0°, θmin = 1.6°
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
h = 109
Tmin = 0.980, Tmax = 0.982k = 88
4175 measured reflectionsl = 1614
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)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.105H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0566P)2 + 0.0371P]
where P = (Fo2 + 2Fc2)/3
1591 reflections(Δ/σ)max = 0.001
191 parametersΔρmax = 0.12 e Å3
5 restraintsΔρmin = 0.17 e Å3
Crystal data top
C6H9N2+·C7H4NO4V = 675.33 (16) Å3
Mr = 275.26Z = 2
Monoclinic, P21Mo Kα radiation
a = 8.0487 (11) ŵ = 0.10 mm1
b = 6.7247 (9) ÅT = 298 K
c = 12.7467 (17) Å0.20 × 0.20 × 0.18 mm
β = 101.802 (7)°
Data collection top
Bruker SMART 1000 CCD area-detector
diffractometer
1591 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2001)
1265 reflections with I > 2σ(I)
Tmin = 0.980, Tmax = 0.982Rint = 0.026
4175 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0395 restraints
wR(F2) = 0.105H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.12 e Å3
1591 reflectionsΔρmin = 0.17 e Å3
191 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
N10.6188 (2)0.2067 (4)0.26835 (16)0.0512 (5)
N20.5065 (3)0.1703 (4)0.08960 (18)0.0686 (7)
N31.1646 (3)0.0460 (4)0.2380 (2)0.0627 (6)
O11.1579 (3)0.0626 (4)0.16070 (19)0.0851 (7)
O21.2502 (3)0.0106 (4)0.32683 (18)0.0880 (7)
O30.7086 (2)0.8232 (3)0.09467 (14)0.0688 (5)
O40.8038 (2)0.8810 (3)0.26794 (14)0.0657 (5)
C11.0666 (3)0.2328 (4)0.2239 (2)0.0516 (6)
C20.9742 (3)0.2807 (4)0.1239 (2)0.0561 (6)
H20.97130.19550.06610.067*
C30.8860 (3)0.4578 (4)0.11130 (19)0.0533 (6)
H30.82370.49270.04410.064*
C40.8890 (3)0.5844 (4)0.19746 (17)0.0466 (5)
C50.9823 (3)0.5302 (4)0.29720 (19)0.0582 (7)
H50.98450.61370.35560.070*
C61.0720 (3)0.3536 (4)0.3108 (2)0.0583 (7)
H61.13480.31770.37770.070*
C70.7922 (3)0.7779 (4)0.1853 (2)0.0514 (6)
C80.6412 (3)0.3019 (5)0.3640 (2)0.0608 (7)
C90.5624 (4)0.4787 (5)0.3702 (3)0.0767 (9)
H90.57700.54680.43500.092*
C100.4597 (4)0.5562 (5)0.2784 (3)0.0770 (9)
H100.40590.67750.28230.092*
C110.4361 (3)0.4599 (5)0.1837 (3)0.0656 (8)
H110.36620.51350.12310.079*
C120.5192 (3)0.2767 (4)0.1779 (2)0.0542 (6)
C130.7530 (4)0.2001 (7)0.4557 (2)0.0845 (10)
H13A0.70530.07310.46720.127*
H13B0.76220.28010.51900.127*
H13C0.86360.18160.43990.127*
H10.676 (4)0.092 (3)0.264 (2)0.080*
H2A0.440 (3)0.204 (5)0.0282 (13)0.080*
H2B0.571 (3)0.064 (3)0.088 (2)0.080*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0508 (11)0.0513 (13)0.0501 (10)0.0044 (10)0.0069 (8)0.0074 (10)
N20.0733 (15)0.0610 (16)0.0586 (13)0.0073 (13)0.0163 (11)0.0064 (13)
N30.0631 (13)0.0528 (15)0.0738 (15)0.0060 (11)0.0178 (11)0.0139 (13)
O10.1048 (16)0.0672 (14)0.0887 (15)0.0245 (13)0.0325 (13)0.0011 (13)
O20.0926 (15)0.0715 (16)0.0917 (14)0.0277 (13)0.0003 (12)0.0160 (13)
O30.0837 (12)0.0484 (11)0.0595 (10)0.0035 (10)0.0198 (8)0.0002 (9)
O40.0827 (12)0.0477 (11)0.0568 (10)0.0119 (10)0.0088 (9)0.0042 (9)
C10.0492 (12)0.0439 (14)0.0621 (14)0.0003 (10)0.0125 (10)0.0091 (12)
C20.0641 (14)0.0527 (16)0.0516 (13)0.0013 (13)0.0118 (11)0.0010 (12)
C30.0603 (14)0.0508 (15)0.0449 (12)0.0013 (12)0.0019 (11)0.0042 (12)
C40.0483 (12)0.0389 (12)0.0485 (12)0.0047 (10)0.0001 (9)0.0038 (10)
C50.0675 (16)0.0501 (15)0.0502 (13)0.0024 (13)0.0042 (11)0.0028 (13)
C60.0625 (15)0.0531 (17)0.0531 (13)0.0044 (12)0.0027 (11)0.0072 (12)
C70.0535 (12)0.0394 (13)0.0539 (13)0.0048 (11)0.0062 (10)0.0004 (12)
C80.0603 (14)0.0689 (17)0.0555 (14)0.0064 (14)0.0173 (11)0.0015 (14)
C90.079 (2)0.078 (2)0.0775 (19)0.0153 (18)0.0268 (16)0.0056 (18)
C100.0680 (17)0.066 (2)0.102 (2)0.0169 (16)0.0304 (16)0.004 (2)
C110.0519 (14)0.0621 (18)0.0810 (19)0.0102 (13)0.0097 (13)0.0150 (16)
C120.0457 (12)0.0548 (16)0.0589 (14)0.0025 (11)0.0033 (10)0.0115 (13)
C130.099 (2)0.102 (3)0.0512 (15)0.022 (2)0.0107 (14)0.0011 (18)
Geometric parameters (Å, º) top
N1—C121.348 (3)C4—C51.386 (3)
N1—C81.356 (3)C4—C71.508 (3)
N1—H10.908 (10)C5—C61.382 (4)
N2—C121.320 (4)C5—H50.9300
N2—H2A0.883 (10)C6—H60.9300
N2—H2B0.889 (10)C8—C91.357 (4)
N3—O11.218 (3)C8—C131.488 (4)
N3—O21.223 (3)C9—C101.389 (4)
N3—C11.475 (3)C9—H90.9300
O3—C71.250 (3)C10—C111.349 (4)
O4—C71.249 (3)C10—H100.9300
C1—C61.368 (4)C11—C121.411 (4)
C1—C21.376 (3)C11—H110.9300
C2—C31.379 (4)C13—H13A0.9600
C2—H20.9300C13—H13B0.9600
C3—C41.386 (3)C13—H13C0.9600
C3—H30.9300
C12—N1—C8123.4 (2)C5—C6—H6120.7
C12—N1—H1117.8 (19)O4—C7—O3125.3 (2)
C8—N1—H1118.7 (19)O4—C7—C4116.4 (2)
C12—N2—H2A122.9 (19)O3—C7—C4118.3 (2)
C12—N2—H2B121.1 (18)N1—C8—C9119.2 (3)
H2A—N2—H2B116 (2)N1—C8—C13115.9 (3)
O1—N3—O2123.8 (2)C9—C8—C13124.9 (3)
O1—N3—C1118.5 (2)C8—C9—C10118.9 (3)
O2—N3—C1117.7 (2)C8—C9—H9120.5
C6—C1—C2122.2 (2)C10—C9—H9120.5
C6—C1—N3118.7 (2)C11—C10—C9121.7 (3)
C2—C1—N3119.1 (2)C11—C10—H10119.2
C1—C2—C3118.5 (2)C9—C10—H10119.2
C1—C2—H2120.7C10—C11—C12119.0 (3)
C3—C2—H2120.7C10—C11—H11120.5
C2—C3—C4120.9 (2)C12—C11—H11120.5
C2—C3—H3119.6N2—C12—N1118.0 (2)
C4—C3—H3119.6N2—C12—C11124.3 (2)
C3—C4—C5118.9 (2)N1—C12—C11117.7 (3)
C3—C4—C7121.6 (2)C8—C13—H13A109.5
C5—C4—C7119.5 (2)C8—C13—H13B109.5
C6—C5—C4120.8 (2)H13A—C13—H13B109.5
C6—C5—H5119.6C8—C13—H13C109.5
C4—C5—H5119.6H13A—C13—H13C109.5
C1—C6—C5118.6 (2)H13B—C13—H13C109.5
C1—C6—H6120.7
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O4i0.91 (2)1.75 (3)2.649 (3)173 (2)
N2—H2A···O3ii0.89 (2)1.94 (2)2.812 (3)170 (2)
N2—H2B···O3i0.89 (2)1.95 (2)2.838 (3)176 (2)
Symmetry codes: (i) x, y1, z; (ii) x+1, y1/2, z.

Experimental details

Crystal data
Chemical formulaC6H9N2+·C7H4NO4
Mr275.26
Crystal system, space groupMonoclinic, P21
Temperature (K)298
a, b, c (Å)8.0487 (11), 6.7247 (9), 12.7467 (17)
β (°) 101.802 (7)
V3)675.33 (16)
Z2
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.20 × 0.20 × 0.18
Data collection
DiffractometerBruker SMART 1000 CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2001)
Tmin, Tmax0.980, 0.982
No. of measured, independent and
observed [I > 2σ(I)] reflections
4175, 1591, 1265
Rint0.026
(sin θ/λ)max1)0.639
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.105, 1.04
No. of reflections1591
No. of parameters191
No. of restraints5
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.12, 0.17

Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O4i0.91 (2)1.75 (3)2.649 (3)173 (2)
N2—H2A···O3ii0.89 (2)1.94 (2)2.812 (3)169.9 (17)
N2—H2B···O3i0.89 (2)1.95 (2)2.838 (3)176 (2)
Symmetry codes: (i) x, y1, z; (ii) x+1, y1/2, z.
 

Acknowledgements

We acknowledge the Natural Science Foundation of China (grant No. 30973651/H3008) for financial support.

References

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