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

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ISSN: 2056-9890

6-Methyl­pyridin-2-amine

aD. Ghitu Institute of Electronic Engineering and Nanotechnologies, 3/3 Academy str., MD-2028, Chisinau, Republic of Moldova, bX-Ray Structural Centre, A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov St, B-334, Moscow 119991, Russian Federation, cDepartment of Chemistry & Biology, New Mexico Highlands University, 803 University Avenue, Las Vegas, NM 87701, USA, and dDepartment of Chemistry & Biology, New Mexico Highlands University, 803 University Avenue, Las mVegas, NM 87701, USA
*Correspondence e-mail: sergiudraguta@gmail.com

(Received 16 November 2012; accepted 21 November 2012; online 28 November 2012)

In the title mol­ecule, C6H8N2, the endocyclic angles are in the range 118.43 (9)–122.65 (10)°. The mol­ecular skeleton is planar (r.m.s. deviation = 0.007 Å). One of the two amino H atoms is involved in an N—H⋯N hydrogen bond, forming an inversion dimer, while the other amino H atom participates in N—H⋯π inter­actions between the dimers, forming layers parallel to (100).

Related literature

For general background to the design of chiral or acentric co-crystals, see: Jacques et al. (1981[Jacques, J., Collet, A. & Wilen, S. H. (1981). In Enantiomers, Racemates, and Resolutions. New York: John Wiley & Sons.]); Miyata (1991[Miyata, S. (1991). In Organic Molecules for Nonlinear Optics and Photonics, edited by J. Messier, F. Kajzar & P. Prasad, P. Dordrecht: Kluwer Academic Publishers.]); Scheiner (1997[Scheiner, S. (1997). In Molecular Interactions. Chichester: John Wiley & Sons.]). For related compounds, see: Büyükgüngör & Odabaşoğlu (2006[Büyükgüngör, O. & Odabaşoǧlu, M. (2006). Acta Cryst. E62, o2749-o2750.]); Chtioui & Jouini (2006[Chtioui, A. & Jouini, A. (2006). Mater. Res. Bull. 41, 569-575.]); Ni et al. (2007[Ni, S.-F., Feng, W.-J., Guo, H. & Jin, Z.-M. (2007). Acta Cryst. E63, o3866.]); Dai et al. (2011[Dai, W.-M., Zhou, H. & Hu, Y.-Q. (2011). Acta Cryst. E67, o578.]); Waddell et al. (2011[Waddell, P. G., Hulse, J. O. S. & Cole, J. M. (2011). Acta Cryst. C67, o255-o258.]).

[Scheme 1]

Experimental

Crystal data
  • C6H8N2

  • Mr = 108.14

  • Monoclinic, P 21 /c

  • a = 9.1006 (11) Å

  • b = 6.2458 (8) Å

  • c = 10.5598 (13) Å

  • β = 100.952 (2)°

  • V = 589.29 (13) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 296 K

  • 0.30 × 0.25 × 0.20 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. University of Göttingen, Germany.]) Tmin = 0.977, Tmax = 0.985

  • 5852 measured reflections

  • 1420 independent reflections

  • 1196 reflections with I > 2σ(I)

  • Rint = 0.030

Refinement
  • R[F2 > 2σ(F2)] = 0.043

  • wR(F2) = 0.130

  • S = 1.00

  • 1420 reflections

  • 82 parameters

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

  • Δρmax = 0.32 e Å−3

  • Δρmin = −0.16 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

Cg is the centroid of the N1/C2–C6 ring.

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H2A⋯N1i 0.896 (17) 2.211 (17) 3.1062 (14) 177.5 (11)
N2—H2BCgii 0.867 (17) 2.674 (16) 3.4875 (12) 163.5 (11)
Symmetry codes: (i) -x, -y+1, -z+2; (ii) [-x, y+{\script{1\over 2}}, -z-{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2001[Bruker (2001). SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

In supramolecular chemistry, intermolecular non-valent interactions, as a factor responsible for the collective properties of solids, are useful chemical tools to control stability, conformation, and assembly of molecules and thus to design new materials with specific physical and chemical properties (Scheiner, 1997). In particular, the absolute asymmetric synthesis that affords optically active compounds starting from achiral reactants in the absence of any external chiral agents is of significant interest (Jacques et al., 1981). To enable the absolute asymmetric synthesis with a high reliability, it is necessary to predict and obtain chiral crystals through self-assembly of the achiral molecules. Such chiral co-crystals are very important as starting solids for the nonlinear optical materials (Miyata, 1991).

In this paper, we determined the structure of the title compound (I), C6H8N2 (Figure 1), with the purpose to study the strengths and directional propensities of its intermolecular non-bonding interactions and to generate in future the chiral molecular co-crystals on the basis of this compound. The structures of several interesting series with pyridine-2-amino-6-methyl derivatives, including acentric organic salts, have been already reported (Büyükgüngör & Odabaşoǧlu, 2006; Chtioui & Jouini, 2006; Ni et al., 2007; Dai et al., 2011; Waddell et al., 2011).

In the molecule of I, endocyclic angles cover the range 118.43 (9)–122.65 (10)°. The endocyclic angles at the C2 and C6 carbon atoms adjacent to the N1 heteroatom are larger than 120°, and those at the other atoms of the ring are smaller than 120°. All the non-hydrogen atoms lie within the same plane (r.m.s. deviation is 0.007 Å). The N2 atom of the amino group has a slightly pyramidalized configuration (sum of the bond angles is 356°).

In the crystal of I, the pyridine N1 atom serves as the acceptor of the N—H···N hydrogen bond (Table 1) which links two molecules into the centrosymmetric dimer (Figure 2). The intermolecular N—H···π interaction (Table 1) between the amino group and pyridine ring further consolidate the crystal packing, forming the layers parallel to (100) (Figure 2).

Related literature top

For general background, see: Jacques et al. (1981); Miyata (1991); Scheiner (1997). For related compounds, see: Büyükgüngör & Odabaşoǧlu (2006); Chtioui & Jouini (2006); Ni et al. (2007); Dai et al. (2011); Waddell et al. (2011).

Experimental top

The compound I was obtained commercially (Aldrich) as a fine-crystalline powder and purified additionally by filtration. Crystals suitable for the X-ray diffraction study were grown by slow evaporation from chloroform solution.

Refinement top

The hydrogen atoms of the amino group were localized in the difference-Fourier map and refined isotropically. The other hydrogen atoms were placed in the calculated positions with C—H = 0.93 Å (CH-groups) and 0.96 Å (CH3-group) and refined in the riding model with fixed isotropic displacement parameters [Uiso(H) = 1.5Ueq(C) for the CH3-group and 1.2Ueq(C) for the CH-groups].

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular structure of I. Displacement ellipsoids are shown at the 50% probability level. H atoms are presented as small spheres of arbitrary radius.
[Figure 2] Fig. 2. A portion of the crystal packing showing intermolecular N—H···N and N—H···π hydrogen bonds as dashed lines.
6-Methylpyridin-2-amine top
Crystal data top
C6H8N2F(000) = 232
Mr = 108.14Dx = 1.219 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2436 reflections
a = 9.1006 (11) Åθ = 2.3–30.0°
b = 6.2458 (8) ŵ = 0.08 mm1
c = 10.5598 (13) ÅT = 296 K
β = 100.952 (2)°Prism, colourless
V = 589.29 (13) Å30.30 × 0.25 × 0.20 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer
1420 independent reflections
Radiation source: fine-focus sealed tube1196 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.030
ϕ and ω scansθmax = 28.0°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
h = 1212
Tmin = 0.977, Tmax = 0.985k = 88
5852 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)] = 0.043Hydrogen site location: difference Fourier map
wR(F2) = 0.130H atoms treated by a mixture of independent and constrained refinement
S = 1.00 w = 1/[σ2(Fo2) + (0.082P)2 + 0.126P]
where P = (Fo2 + 2Fc2)/3
1420 reflections(Δ/σ)max < 0.001
82 parametersΔρmax = 0.32 e Å3
0 restraintsΔρmin = 0.16 e Å3
Crystal data top
C6H8N2V = 589.29 (13) Å3
Mr = 108.14Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.1006 (11) ŵ = 0.08 mm1
b = 6.2458 (8) ÅT = 296 K
c = 10.5598 (13) Å0.30 × 0.25 × 0.20 mm
β = 100.952 (2)°
Data collection top
Bruker APEXII CCD
diffractometer
1420 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
1196 reflections with I > 2σ(I)
Tmin = 0.977, Tmax = 0.985Rint = 0.030
5852 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0430 restraints
wR(F2) = 0.130H atoms treated by a mixture of independent and constrained refinement
S = 1.00Δρmax = 0.32 e Å3
1420 reflectionsΔρmin = 0.16 e Å3
82 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
N10.17331 (10)0.50475 (14)0.92049 (8)0.0227 (3)
N20.00315 (12)0.77129 (17)0.90952 (10)0.0311 (3)
H2A0.0502 (18)0.693 (3)0.9607 (16)0.040 (4)*
H2B0.0533 (18)0.877 (3)0.8697 (15)0.038 (4)*
C20.11252 (12)0.68485 (17)0.86263 (10)0.0234 (3)
C30.16561 (13)0.77898 (18)0.75860 (11)0.0271 (3)
H30.12190.90290.71960.033*
C40.28303 (13)0.68378 (19)0.71621 (10)0.0281 (3)
H40.31910.74190.64700.034*
C50.34831 (12)0.49983 (18)0.77700 (10)0.0267 (3)
H50.42910.43490.75000.032*
C60.29036 (12)0.41577 (17)0.87838 (10)0.0234 (3)
C70.35535 (13)0.21888 (19)0.94938 (11)0.0307 (3)
H7A0.41720.25971.02980.046*
H7B0.41460.14290.89800.046*
H7C0.27580.12820.96560.046*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0270 (5)0.0204 (4)0.0207 (4)0.0013 (3)0.0052 (3)0.0013 (3)
N20.0372 (6)0.0251 (5)0.0331 (5)0.0101 (4)0.0122 (4)0.0046 (4)
C20.0256 (5)0.0207 (5)0.0233 (5)0.0009 (4)0.0029 (4)0.0030 (4)
C30.0292 (6)0.0236 (5)0.0271 (5)0.0005 (4)0.0018 (4)0.0045 (4)
C40.0271 (6)0.0331 (6)0.0240 (5)0.0056 (4)0.0047 (4)0.0045 (4)
C50.0243 (5)0.0315 (6)0.0251 (5)0.0014 (4)0.0065 (4)0.0009 (4)
C60.0254 (5)0.0225 (5)0.0218 (5)0.0002 (4)0.0031 (4)0.0027 (4)
C70.0351 (6)0.0269 (6)0.0316 (6)0.0078 (5)0.0098 (5)0.0031 (4)
Geometric parameters (Å, º) top
N1—C21.3476 (14)C4—C51.3929 (16)
N1—C61.3496 (13)C4—H40.9300
N2—C21.3575 (14)C5—C61.3837 (15)
N2—H2A0.896 (17)C5—H50.9300
N2—H2B0.867 (17)C6—C71.5019 (15)
C2—C31.4099 (15)C7—H7A0.9600
C3—C41.3702 (16)C7—H7B0.9600
C3—H30.9300C7—H7C0.9600
C2—N1—C6118.43 (9)C6—C5—C4118.53 (10)
C2—N2—H2A119.7 (10)C6—C5—H5120.7
C2—N2—H2B120.1 (10)C4—C5—H5120.7
H2A—N2—H2B116.2 (14)N1—C6—C5122.65 (10)
N1—C2—N2116.52 (10)N1—C6—C7115.68 (9)
N1—C2—C3121.96 (10)C5—C6—C7121.67 (10)
N2—C2—C3121.51 (10)C6—C7—H7A109.5
C4—C3—C2118.53 (10)C6—C7—H7B109.5
C4—C3—H3120.7H7A—C7—H7B109.5
C2—C3—H3120.7C6—C7—H7C109.5
C3—C4—C5119.88 (10)H7A—C7—H7C109.5
C3—C4—H4120.1H7B—C7—H7C109.5
C5—C4—H4120.1
C6—N1—C2—N2178.81 (9)C3—C4—C5—C61.01 (17)
C6—N1—C2—C31.34 (15)C2—N1—C6—C51.20 (16)
N1—C2—C3—C40.31 (17)C2—N1—C6—C7178.40 (9)
N2—C2—C3—C4179.84 (10)C4—C5—C6—N10.04 (17)
C2—C3—C4—C50.88 (17)C4—C5—C6—C7179.54 (10)
Hydrogen-bond geometry (Å, º) top
Cg is the centroid of the N1/C2–C6 ring.
D—H···AD—HH···AD···AD—H···A
N2—H2A···N1i0.896 (17)2.211 (17)3.1062 (14)177.5 (11)
N2—H2B···Cgii0.867 (17)2.674 (16)3.4875 (12)163.5 (11)
Symmetry codes: (i) x, y+1, z+2; (ii) x, y+1/2, z1/2.

Experimental details

Crystal data
Chemical formulaC6H8N2
Mr108.14
Crystal system, space groupMonoclinic, P21/c
Temperature (K)296
a, b, c (Å)9.1006 (11), 6.2458 (8), 10.5598 (13)
β (°) 100.952 (2)
V3)589.29 (13)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.30 × 0.25 × 0.20
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.977, 0.985
No. of measured, independent and
observed [I > 2σ(I)] reflections
5852, 1420, 1196
Rint0.030
(sin θ/λ)max1)0.660
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.043, 0.130, 1.00
No. of reflections1420
No. of parameters82
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.32, 0.16

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2001), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
Cg is the centroid of the N1/C2–C6 ring.
D—H···AD—HH···AD···AD—H···A
N2—H2A···N1i0.896 (17)2.211 (17)3.1062 (14)177.5 (11)
N2—H2B···Cgii0.867 (17)2.674 (16)3.4875 (12)163.5 (11)
Symmetry codes: (i) x, y+1, z+2; (ii) x, y+1/2, z1/2.
 

Acknowledgements

The authors are grateful to the NSF for support via DMR grant 0934212 (PREM) and CHE 0832622.

References

First citationBruker (2001). SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationBruker (2005). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationBüyükgüngör, O. & Odabaşoǧlu, M. (2006). Acta Cryst. E62, o2749–o2750.  Web of Science CSD CrossRef IUCr Journals
First citationChtioui, A. & Jouini, A. (2006). Mater. Res. Bull. 41, 569–575.  Web of Science CSD CrossRef CAS
First citationDai, W.-M., Zhou, H. & Hu, Y.-Q. (2011). Acta Cryst. E67, o578.  Web of Science CSD CrossRef IUCr Journals
First citationJacques, J., Collet, A. & Wilen, S. H. (1981). In Enantiomers, Racemates, and Resolutions. New York: John Wiley & Sons.
First citationMiyata, S. (1991). In Organic Molecules for Nonlinear Optics and Photonics, edited by J. Messier, F. Kajzar & P. Prasad, P. Dordrecht: Kluwer Academic Publishers.
First citationNi, S.-F., Feng, W.-J., Guo, H. & Jin, Z.-M. (2007). Acta Cryst. E63, o3866.  Web of Science CSD CrossRef IUCr Journals
First citationScheiner, S. (1997). In Molecular Interactions. Chichester: John Wiley & Sons.
First citationSheldrick, G. M. (2003). SADABS. University of Göttingen, Germany.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationWaddell, P. G., Hulse, J. O. S. & Cole, J. M. (2011). Acta Cryst. C67, o255–o258.  Web of Science CSD CrossRef IUCr Journals

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ISSN: 2056-9890
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