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Acta Crystallogr Sect E Struct Rep Online. 2009 May 1; 65(Pt 5): o1168.
Published online 2009 April 30. doi:  10.1107/S1600536809015591
PMCID: PMC2977833

N 1,N 2-Bis(6-methyl-2-pyrid­yl)formamidine

Abstract

In the crystal structure of the title mol­ecule, C13H14N4, the two pyridyl rings are not coplanar but twisted about the C—N bond with an inter­planar angle of 71.1 (1)°. In the crystal, the mol­ecules form dimers, situated on crystallographic centres of inversion, which are connected via a pair of N—H(...)N hydrogen bonds. C—H(...)π-electron ring inter­actions are also present in the crystal structure. The title mol­ecule adopts an s–cis–anti–s–cis conformation in the solid state.

Related literature

For related structures, see: Wu et al. (2009 [triangle]); Liang et al. (2003 [triangle]); Yang et al. (2000 [triangle]); Radak et al. (2001 [triangle]). For the synthesis, see: Roberts (1949 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-o1168-scheme1.jpg

Experimental

Crystal data

  • C13H14N4
  • M r = 226.28
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o1168-efi1.jpg
  • a = 6.0364 (4) Å
  • b = 19.6697 (14) Å
  • c = 10.4040 (7) Å
  • β = 96.081 (1)°
  • V = 1228.36 (15) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.08 mm−1
  • T = 298 K
  • 0.5 × 0.5 × 0.3 mm

Data collection

  • Bruker SMART 1000 diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 1997 [triangle]) T min = 0.683, T max = 0.792 (expected range = 0.842–0.977)
  • 7002 measured reflections
  • 2912 independent reflections
  • 2313 reflections with I > 2σ(I)
  • R int = 0.110

Refinement

  • R[F 2 > 2σ(F 2)] = 0.060
  • wR(F 2) = 0.148
  • S = 1.09
  • 2912 reflections
  • 161 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.16 e Å−3
  • Δρmin = −0.21 e Å−3

Data collection: SMART (Bruker, 1997 [triangle]); cell refinement: SAINT (Bruker, 1997 [triangle]); data reduction: SAINT and SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809015591/fb2144sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809015591/fb2144Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

We are grateful to the National Science Council of the Republic of China for the support. This research was also supported by the project of the specific research fields in Chung-Yuan Christian University, Taiwan, under grant CYCU-97-CR—CH.

supplementary crystallographic information

Comment

The title molecule as well as its anion have been used as bridging ligands in the coordination chemistry (Liang et al., 2003; Yang et al., 2000; Radak et al., 2001). In the present work, the structure of the title molecule (Fig. 1) has been determined to explore its ligand conformation.

The molecules form dimers that are interconnected via a pair of N—H···N hydrogen bonds (Tab. 1, Fig. 2). Moreover, there are also C—H···π-electron ring interactions (Tab. 1) in the structure. The conformation in the title molecule in the structure is s-cis-anti-s-cis. This conformation is in contrast to that one found in N1,N2-bis(2-pyridyl)formamidine, which is s-trans-syn-s-cis (Wu et al. , 2009).

Experimental

The title compound was prepared according to the procedure described by Roberts (1949). 2-Aminopyridine (12.96 g, 0.12 mol) and triethyl orthoformate (11.8 g, 0.06 mol) were placed under nitrogen into a flask. The mixture was then refluxed for 8 h to give a brown solid. Dichloromethane (10 ml) was then added to dissolve the solid and then hexane (25 ml) was added to induce the precipitation. The precipitate was filtered and dried under vacuum to give a light yellow solid with a yield of 83%. By dissolving the solid in dichloromethane, followed by allowing the solution to evaporate slowly under air, several yellow crystals suitable for X-ray crystallography were obtained. One block crystal with size of 0.5 x 0.5 x 0.3 mm was used for data collection.

Refinement

All the hydrogen atoms were discernible in the difference Fourier maps. However, they were situated into the idealized positions and constrained by the riding atom approximation: C—Hmethyl = 0.96 Å while the methyls were allowed to rotate about their respective axes; C—Haryl = 0.93 Å; Uiso(Hmethyl) = 1.5Ueq(Cmethyl); Uiso(Haryl) = 1.2Ueq(Caryl). The amine hydrogen atom (H3N) that is involved in the N-H···N hydrogen bond was freely refined.

Figures

Fig. 1.
The title molecule with the labelling scheme. The displacement ellipsoids are drawn at the 30% probability level.
Fig. 2.
View on the dimers bind by the hydrogen bonds, which are shown as dashed lines. Symmetry code: (i) -x+1, -y+1, -z+2.

Crystal data

C13H14N4F(000) = 480
Mr = 226.28Dx = 1.224 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 7002 reflections
a = 6.0364 (4) Åθ = 2.1–28.3°
b = 19.6697 (14) ŵ = 0.08 mm1
c = 10.4040 (7) ÅT = 298 K
β = 96.081 (1)°Block, yellow
V = 1228.36 (15) Å30.5 × 0.5 × 0.3 mm
Z = 4

Data collection

Bruker SMART 1000 diffractometer2912 independent reflections
Radiation source: fine-focus sealed tube2313 reflections with I > 2σ(I)
graphiteRint = 0.110
[var phi] and ω scansθmax = 28.3°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 1997)h = −8→8
Tmin = 0.683, Tmax = 0.792k = −22→26
7002 measured reflectionsl = −13→8

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.060H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.148w = 1/[σ2(Fo2) + (0.0514P)2 + 0.2913P] where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
2912 reflectionsΔρmax = 0.16 e Å3
161 parametersΔρmin = −0.21 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
50 constraintsExtinction coefficient: 0.050 (6)
Primary atom site location: structure-invariant direct methods

Special details

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)

xyzUiso*/Ueq
N10.1831 (2)0.44487 (7)0.66067 (13)0.0459 (3)
N20.2674 (2)0.49243 (7)0.86759 (12)0.0470 (3)
N30.5357 (2)0.57705 (7)0.89283 (13)0.0497 (4)
N40.4953 (2)0.67233 (7)0.76126 (13)0.0481 (3)
C10.1286 (4)0.39836 (12)0.44484 (19)0.0733 (6)
H1B0.17750.43920.40590.110*
H1C0.01400.37720.38740.110*
H1D0.25210.36770.46130.110*
C20.0383 (3)0.41552 (8)0.56991 (16)0.0514 (4)
C3−0.1794 (3)0.40215 (10)0.5912 (2)0.0620 (5)
H3A−0.27800.38320.52620.074*
C4−0.2488 (3)0.41725 (10)0.7103 (2)0.0640 (5)
H4B−0.39470.40830.72630.077*
C5−0.1007 (3)0.44564 (9)0.80515 (18)0.0538 (4)
H5A−0.14230.45490.88690.065*
C60.1131 (3)0.46006 (8)0.77451 (15)0.0433 (3)
C70.3682 (3)0.54351 (8)0.82345 (15)0.0455 (4)
H7A0.32380.55810.73960.055*
C80.6236 (3)0.63789 (8)0.85033 (15)0.0457 (4)
C90.8327 (3)0.65966 (10)0.90180 (19)0.0627 (5)
H9A0.91870.63410.96350.075*
C100.9085 (4)0.72061 (12)0.8581 (2)0.0751 (6)
H10A1.04760.73700.89080.090*
C110.7783 (4)0.75724 (10)0.7662 (2)0.0684 (6)
H11A0.82770.79860.73670.082*
C120.5739 (3)0.73169 (9)0.71856 (17)0.0540 (4)
C130.4238 (4)0.76673 (12)0.6146 (2)0.0764 (6)
H13A0.27240.76400.63450.115*
H13B0.43670.74500.53300.115*
H13C0.46660.81360.60970.115*
H3N0.602 (3)0.5592 (11)0.966 (2)0.064 (6)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.0435 (7)0.0473 (7)0.0455 (7)0.0045 (5)−0.0024 (5)−0.0009 (5)
N20.0501 (7)0.0479 (7)0.0413 (7)−0.0025 (6)−0.0021 (5)0.0012 (5)
N30.0584 (8)0.0448 (7)0.0428 (7)−0.0054 (6)−0.0082 (6)0.0033 (6)
N40.0531 (7)0.0449 (7)0.0455 (7)0.0010 (6)0.0018 (6)0.0001 (6)
C10.0852 (14)0.0787 (14)0.0535 (10)0.0134 (12)−0.0042 (10)−0.0171 (10)
C20.0541 (9)0.0462 (9)0.0510 (9)0.0083 (7)−0.0082 (7)−0.0049 (7)
C30.0515 (9)0.0568 (10)0.0727 (12)−0.0009 (8)−0.0160 (8)−0.0071 (9)
C40.0404 (8)0.0656 (12)0.0847 (14)−0.0037 (8)−0.0002 (8)0.0039 (10)
C50.0466 (9)0.0583 (10)0.0567 (10)0.0035 (7)0.0068 (7)0.0021 (8)
C60.0425 (8)0.0403 (7)0.0457 (8)0.0032 (6)−0.0020 (6)0.0031 (6)
C70.0513 (9)0.0441 (8)0.0394 (7)0.0019 (7)−0.0033 (6)0.0004 (6)
C80.0529 (9)0.0426 (8)0.0406 (8)−0.0018 (6)0.0006 (6)−0.0041 (6)
C90.0642 (11)0.0625 (11)0.0569 (10)−0.0101 (9)−0.0145 (8)0.0035 (8)
C100.0751 (13)0.0725 (13)0.0732 (13)−0.0292 (11)−0.0123 (10)−0.0006 (10)
C110.0855 (14)0.0527 (10)0.0654 (12)−0.0207 (10)0.0010 (10)0.0008 (9)
C120.0693 (11)0.0423 (8)0.0506 (9)−0.0011 (8)0.0069 (8)−0.0017 (7)
C130.0903 (15)0.0602 (12)0.0768 (14)0.0066 (11)0.0008 (11)0.0175 (10)

Geometric parameters (Å, °)

N1—C61.333 (2)C4—C51.378 (3)
N1—C21.347 (2)C4—H4B0.9300
N2—C71.285 (2)C5—C61.391 (2)
N2—C61.4212 (19)C5—H5A0.9300
N3—C71.350 (2)C7—H7A0.9300
N3—C81.400 (2)C8—C91.386 (2)
N3—H3N0.90 (2)C9—C101.377 (3)
N4—C81.329 (2)C9—H9A0.9300
N4—C121.353 (2)C10—C111.376 (3)
C1—C21.502 (3)C10—H10A0.9300
C1—H1B0.9600C11—C121.375 (3)
C1—H1C0.9600C11—H11A0.9300
C1—H1D0.9600C12—C131.503 (3)
C2—C31.380 (3)C13—H13A0.9600
C3—C41.382 (3)C13—H13B0.9600
C3—H3A0.9300C13—H13C0.9600
C6—N1—C2118.40 (14)C5—C6—N2119.49 (15)
C7—N2—C6114.08 (13)N2—C7—N3123.18 (14)
C7—N3—C8122.43 (14)N2—C7—H7A118.4
C7—N3—H3N120.3 (14)N3—C7—H7A118.4
C8—N3—H3N117.1 (14)N4—C8—C9123.49 (16)
C8—N4—C12118.06 (15)N4—C8—N3116.34 (14)
C2—C1—H1B109.5C9—C8—N3120.17 (15)
C2—C1—H1C109.5C10—C9—C8117.52 (18)
H1B—C1—H1C109.5C10—C9—H9A121.2
C2—C1—H1D109.5C8—C9—H9A121.2
H1B—C1—H1D109.5C11—C10—C9120.01 (18)
H1C—C1—H1D109.5C11—C10—H10A120.0
N1—C2—C3121.81 (16)C9—C10—H10A120.0
N1—C2—C1115.82 (17)C12—C11—C10118.93 (18)
C3—C2—C1122.37 (16)C12—C11—H11A120.5
C2—C3—C4119.16 (16)C10—C11—H11A120.5
C2—C3—H3A120.4N4—C12—C11121.97 (17)
C4—C3—H3A120.4N4—C12—C13115.27 (17)
C5—C4—C3119.60 (17)C11—C12—C13122.75 (17)
C5—C4—H4B120.2C12—C13—H13A109.5
C3—C4—H4B120.2C12—C13—H13B109.5
C4—C5—C6117.76 (17)H13A—C13—H13B109.5
C4—C5—H5A121.1C12—C13—H13C109.5
C6—C5—H5A121.1H13A—C13—H13C109.5
N1—C6—C5123.18 (15)H13B—C13—H13C109.5
N1—C6—N2117.34 (14)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N3—H3N···N2i0.89 (2)2.09 (2)2.9775 (19)173 (2)
C1—H1B···Cg1ii0.962.833.644 (2)143
C11—H11A···Cg1iii0.932.963.757 (2)145

Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x, y+3/2, −z+3/2; (iii) −x+1, −y, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FB2144).

References

  • Bruker (1997). SADABS ,SAINT and SMART Bruker AXS Inc., Madison, Wisconsin, USA.
  • Liang, H.-C., Wu, Y.-Y., Chang, F.-C., Yang, P.-Y., Chen, J.-D. & Wang, J.-C. (2003). J. Organomet. Chem.669, 182–188.
  • Radak, S., Ni, Y., Xu, G., Shaffer, K. L. & Ren, T. (2001). Inorg. Chim. Acta, 321, 200–204.
  • Roberts, R. M. (1949). J. Org. Chem.14, 277–284. [PubMed]
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Wu, C.-J., Su, C.-W., Yeh, C.-W., Chen, J.-D. & Wang, J.-C. (2009). Acta Cryst. E65, o536. [PMC free article] [PubMed]
  • Yang, P.-Y., Chang, F.-C., Suen, M.-C., Chen, J.-D., Feng, T.-C. & Wang, J.-C. (2000). J. Organomet. Chem.596, 226–231.

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