N1,N2-Bis(2-pyrid­yl)formamidine

Wu, C.-J.; Su, C.-W.; Yeh, C.-W.; Chen, J.-D.; Wang, J.-C.

doi:10.1107/S1600536809004851

organic compounds

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ISSN: 2056-9890

Volume 65| Part 3| March 2009| Page o536

doi:10.1107/S1600536809004851

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N¹,N²-Bis(2-pyridyl)formamidine

Chia-Jun Wu,^a Chang-Wei Su,^a Chun-Wei Yeh,^a Jhy-Der Chen ^a ^* and Ju-Chun Wang ^b

^aDepartment of Chemistry, Chung-Yuan Christian University, Chung-Li, Taiwan, and ^bDepartment of Chemistry, Soochow University, Taipei, Taiwan
^*Correspondence e-mail: jdchen@cycu.edu.tw

(Received 4 February 2009; accepted 10 February 2009; online 18 February 2009)

In the crystal structure of the title compound, C₁₁H₁₀N₄, the dihedral angle between the two pyridyl rings is 36.1 (1)°. The molecules are connected via two strong N—H⋯N and two weak C—H⋯N hydrogen bonds into dimers, which are located on centers of inversion. This compound adopts the s–trans–anti–s–cis conformation in the solid state.

Related literature

For similar structures, see: Liang et al. (2003 ); Yang et al. (2000 ); Radak et al. (2001 ); Cotton et al. (1998 ). For the synthesis, see: Roberts (1949 ).

Experimental

Crystal data

C₁₁H₁₀N₄
M_r = 198.23
Monoclinic, P 2/n
a = 11.0411 (14) Å
b = 4.3904 (5) Å
c = 20.789 (3) Å
β = 98.725 (2)°
V = 996.1 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 298 K
0.44 × 0.12 × 0.08 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: empirical (using intensity measurements) (SADABS; Bruker, 1997 ) T_min = 0.983, T_max = 0.995
3628 measured reflections
1697 independent reflections
1251 reflections with I > 2σ(I)
R_int = 0.041

Refinement

R[F² > 2σ(F²)] = 0.059
wR(F²) = 0.143
S = 1.13
1697 reflections
141 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.14 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3N⋯N2ⁱ	0.90 (3)	2.14 (3)	3.044 (3)	175 (2)
C8—H8A⋯N1ⁱ	0.93	2.51	3.388 (4)	157
Symmetry code: (i) -x+1, -y, -z+1.

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

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809004851/nc2134sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809004851/nc2134Isup2.hkl

checkCIF report

Comment top

The title compound and its anion have been used as bridging ligands in coordination chemistry (Liang et al., 2003; Yang et al., 2000; Radak et al., 2001; Cotton et al., 1998). In the present work, the structure of the title compound (Fig. 1) has been determined to explore its ligand conformation. In the crystal structure of the title compound the molecule is in a s-trans-anti-s-cis conformation. This conformation is different from that in the Re complex, which is s-cis-syn-s-cis(Liang et al., 2003).

Thus, the conformation of the free ligand has been changed upon coordination to the metal center. The molecules are connected via two strong N—H—N and two weak C—H—N hydrogen bonds into dimers, which are located on centres of inversion (Fig. 2),

Related literature top

For similar structures, see: Liang et al. (2003); Yang et al. (2000); Radak et al. (2001); Cotton et al. (1998). For the synthesis, see: Roberts (1949).

Experimental top

The title compound was prepared according to a published procedure (Roberts, 1949). 2-Aminopyridine (11.28 g, 0.12 mol) and triethyl orthoformate (8.88 g, 0.06 mol) were placed in a flask under nitrogen. The mixture was then refluxed for 8 h to give a brown solid. Dichloromethane was then added to dissolve the solid and then hexanes added to induce the precipitate. The precipitate was filtered and dried under vacuum to give a light yellow solid with a yield of 82 %. Crystals suitable for X-ray crystallography were obtained by dissolving the product in dichloromethane, followed by slow evaporation of the solvent.

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997) and SHELXTL (Sheldrick, 2008); 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

	Fig. 1. : An ORTEP diagram showing the structure of the title compound with labeling and displacement ellipsoids drawn at the 30 % probability level.
	Fig. 2. : View onto the dimers formed by intermolecular hydrogen bonding, which is shown as dashed lines. Symmetry code: (i) -x+1, -y, -z+1.

N¹,N²-Bis(2-pyridyl)formamidine top

Crystal data top

C₁₁H₁₀N₄	F(000) = 416
M_r = 198.23	D_x = 1.322 Mg m⁻³
Monoclinic, P2/n	Mo Kα radiation, λ = 0.71073 Å
a = 11.0411 (14) Å	Cell parameters from 1493 reflections
b = 4.3904 (5) Å	θ = 2.0–25.1°
c = 20.789 (3) Å	µ = 0.09 mm⁻¹
β = 98.725 (2)°	T = 298 K
V = 996.1 (2) Å³	Column, colorless
Z = 4	0.44 × 0.12 × 0.08 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	1697 independent reflections
Radiation source: fine-focus sealed tube	1251 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.041
ϕ and ω scans	θ_max = 25.1°, θ_min = 2.0°
Absorption correction: empirical (using intensity measurements) (SADABS; Bruker, 1997)	h = −13→8
T_min = 0.983, T_max = 0.995	k = −5→4
3628 measured reflections	l = −23→24

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.059	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.143	w = 1/[σ²(F_o²) + (0.0509P)² + 0.3516P] where P = (F_o² + 2F_c²)/3
S = 1.13	(Δ/σ)_max < 0.001
1697 reflections	Δρ_max = 0.14 e Å⁻³
141 parameters	Δρ_min = −0.19 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.024 (4)

Crystal data top

C₁₁H₁₀N₄	V = 996.1 (2) Å³
M_r = 198.23	Z = 4
Monoclinic, P2/n	Mo Kα radiation
a = 11.0411 (14) Å	µ = 0.09 mm⁻¹
b = 4.3904 (5) Å	T = 298 K
c = 20.789 (3) Å	0.44 × 0.12 × 0.08 mm
β = 98.725 (2)°

Data collection top

Bruker SMART CCD area-detector diffractometer	1697 independent reflections
Absorption correction: empirical (using intensity measurements) (SADABS; Bruker, 1997)	1251 reflections with I > 2σ(I)
T_min = 0.983, T_max = 0.995	R_int = 0.041
3628 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.059	0 restraints
wR(F²) = 0.143	H atoms treated by a mixture of independent and constrained refinement
S = 1.13	Δρ_max = 0.14 e Å⁻³
1697 reflections	Δρ_min = −0.19 e Å⁻³
141 parameters

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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	0.7611 (2)	−0.1912 (6)	0.64055 (11)	0.0633 (7)
N2	0.66575 (17)	−0.0267 (5)	0.53928 (10)	0.0502 (6)
N3	0.58806 (19)	0.2810 (5)	0.45290 (10)	0.0482 (6)
N4	0.71668 (18)	0.5763 (5)	0.39863 (10)	0.0536 (6)
C1	0.8583 (3)	−0.3057 (8)	0.67908 (14)	0.0731 (9)
H1B	0.8510	−0.3453	0.7223	0.088*
C2	0.9685 (3)	−0.3685 (8)	0.65886 (15)	0.0708 (9)
H2B	1.0342	−0.4453	0.6876	0.085*
C3	0.9785 (3)	−0.3143 (7)	0.59503 (15)	0.0675 (8)
H3A	1.0516	−0.3553	0.5796	0.081*
C4	0.8802 (2)	−0.1991 (7)	0.55388 (13)	0.0559 (7)
H4B	0.8856	−0.1632	0.5103	0.067*
C5	0.7723 (2)	−0.1370 (6)	0.57845 (12)	0.0483 (6)
C6	0.6813 (2)	0.1693 (6)	0.49522 (12)	0.0480 (6)
H6A	0.7604	0.2361	0.4926	0.058*
C7	0.6029 (2)	0.4915 (6)	0.40425 (12)	0.0471 (6)
C8	0.5000 (2)	0.6016 (6)	0.36432 (13)	0.0558 (7)
H8A	0.4219	0.5384	0.3699	0.067*
C9	0.5161 (3)	0.8048 (7)	0.31657 (14)	0.0632 (8)
H9A	0.4487	0.8817	0.2891	0.076*
C10	0.6329 (3)	0.8952 (7)	0.30926 (14)	0.0636 (8)
H10A	0.6462	1.0314	0.2768	0.076*
C11	0.7286 (2)	0.7769 (7)	0.35157 (13)	0.0596 (8)
H11A	0.8073	0.8405	0.3473	0.072*
H3N	0.512 (3)	0.203 (6)	0.4525 (12)	0.058 (8)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0500 (13)	0.0826 (18)	0.0570 (14)	−0.0025 (12)	0.0077 (11)	0.0050 (13)
N2	0.0373 (11)	0.0612 (14)	0.0520 (12)	−0.0022 (10)	0.0069 (9)	−0.0015 (11)
N3	0.0370 (11)	0.0514 (13)	0.0562 (13)	−0.0033 (10)	0.0070 (10)	0.0006 (11)
N4	0.0438 (12)	0.0592 (14)	0.0597 (13)	−0.0022 (10)	0.0144 (10)	−0.0004 (11)
C1	0.0608 (18)	0.097 (2)	0.0590 (17)	0.0002 (18)	0.0027 (14)	0.0105 (17)
C2	0.0492 (16)	0.084 (2)	0.075 (2)	0.0047 (16)	−0.0052 (14)	0.0032 (18)
C3	0.0455 (15)	0.079 (2)	0.079 (2)	0.0036 (15)	0.0121 (14)	−0.0029 (18)
C4	0.0445 (14)	0.0701 (19)	0.0538 (15)	0.0014 (13)	0.0100 (12)	−0.0024 (14)
C5	0.0407 (13)	0.0499 (15)	0.0541 (15)	−0.0058 (11)	0.0061 (11)	−0.0039 (12)
C6	0.0383 (13)	0.0518 (15)	0.0547 (14)	−0.0026 (12)	0.0100 (11)	−0.0094 (13)
C7	0.0435 (14)	0.0472 (14)	0.0515 (14)	0.0005 (12)	0.0106 (11)	−0.0090 (13)
C8	0.0458 (15)	0.0579 (17)	0.0631 (16)	0.0007 (13)	0.0067 (12)	−0.0030 (14)
C9	0.0622 (18)	0.0610 (18)	0.0649 (18)	0.0097 (15)	0.0051 (14)	0.0005 (15)
C10	0.0713 (19)	0.0610 (19)	0.0617 (17)	0.0038 (15)	0.0207 (15)	0.0031 (15)
C11	0.0535 (16)	0.0632 (19)	0.0660 (18)	−0.0029 (14)	0.0214 (14)	−0.0008 (15)

Geometric parameters (Å, º) top

N1—C1	1.337 (4)	C3—C4	1.372 (4)
N1—C5	1.337 (3)	C3—H3A	0.9300
N2—C6	1.287 (3)	C4—C5	1.392 (3)
N2—C5	1.411 (3)	C4—H4B	0.9300
N3—C6	1.342 (3)	C6—H6A	0.9300
N3—C7	1.398 (3)	C7—C8	1.388 (3)
N3—H3N	0.90 (3)	C8—C9	1.366 (4)
N4—C7	1.332 (3)	C8—H8A	0.9300
N4—C11	1.337 (3)	C9—C10	1.380 (4)
C1—C2	1.374 (4)	C9—H9A	0.9300
C1—H1B	0.9300	C10—C11	1.370 (4)
C2—C3	1.369 (4)	C10—H10A	0.9300
C2—H2B	0.9300	C11—H11A	0.9300

C1—N1—C5	117.5 (2)	C4—C5—N2	122.7 (2)
C6—N2—C5	116.7 (2)	N2—C6—N3	122.6 (2)
C6—N3—C7	123.6 (2)	N2—C6—H6A	118.7
C6—N3—H3N	118.9 (17)	N3—C6—H6A	118.7
C7—N3—H3N	117.1 (17)	N4—C7—C8	123.2 (3)
C7—N4—C11	116.5 (2)	N4—C7—N3	117.6 (2)
N1—C1—C2	124.1 (3)	C8—C7—N3	119.2 (2)
N1—C1—H1B	118.0	C9—C8—C7	118.5 (3)
C2—C1—H1B	118.0	C9—C8—H8A	120.8
C3—C2—C1	117.8 (3)	C7—C8—H8A	120.8
C3—C2—H2B	121.1	C8—C9—C10	119.6 (3)
C1—C2—H2B	121.1	C8—C9—H9A	120.2
C2—C3—C4	119.7 (3)	C10—C9—H9A	120.2
C2—C3—H3A	120.1	C11—C10—C9	117.6 (3)
C4—C3—H3A	120.1	C11—C10—H10A	121.2
C3—C4—C5	118.9 (3)	C9—C10—H10A	121.2
C3—C4—H4B	120.6	N4—C11—C10	124.6 (3)
C5—C4—H4B	120.6	N4—C11—H11A	117.7
N1—C5—C4	122.0 (2)	C10—C11—H11A	117.7
N1—C5—N2	115.2 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3N···N2ⁱ	0.90 (3)	2.14 (3)	3.044 (3)	175 (2)
C8—H8A···N1ⁱ	0.93	2.51	3.388 (4)	157

Symmetry code: (i) −x+1, −y, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₁H₁₀N₄
M_r	198.23
Crystal system, space group	Monoclinic, P2/n
Temperature (K)	298
a, b, c (Å)	11.0411 (14), 4.3904 (5), 20.789 (3)
β (°)	98.725 (2)
V (Å³)	996.1 (2)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.44 × 0.12 × 0.08

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Empirical (using intensity measurements) (SADABS; Bruker, 1997)
T_min, T_max	0.983, 0.995
No. of measured, independent and observed [I > 2σ(I)] reflections	3628, 1697, 1251
R_int	0.041
(sin θ/λ)_max (Å⁻¹)	0.596

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.059, 0.143, 1.13
No. of reflections	1697
No. of parameters	141
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.14, −0.19

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997) and SHELXTL (Sheldrick, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3N···N2ⁱ	0.90 (3)	2.14 (3)	3.044 (3)	175 (2)
C8—H8A···N1ⁱ	0.93	2.51	3.388 (4)	156.7

Symmetry code: (i) −x+1, −y, −z+1.

Acknowledgements

We are grateful to the National Science Council of the Republic of China for support. This research was also supported by the project of the specific research fields in Chung-Yuan Christian University, Taiwan, under grant No. CYCU-97-CR-CH.

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