1,4-Bis(3-pyridylmethyl­eneamino­meth­yl)benzene

Abstract

The title compound, C₂₀H₁₈N₄, is a flexible 3,3′-bipyridyl-type ligand with a long spacer group between the two pyridyl functions. The mol­ecule crystallizes around an inversion center, with one half-mol­ecule in the asymmetric unit and a dihedral angle of 71.85 (8)° between the pyridine ring and the central benzene ring.

Related literature

For background information on bipyridyl-type Schiff base ligands, see: Cho et al. (2006 ▶); Haga et al. (1985 ▶); Mahmoudi et al. (2007 ▶); Wang et al. (2008 ▶). Haga et al. (1985 ▶) describe the synthesis of the title compound.

Experimental

Crystal data

• C₂₀H₁₈N₄

• M _r = 314.38

• Monoclinic,

• a = 6.0990 (11) Å

• b = 14.589 (3) Å

• c = 9.9481 (18) Å

• β = 107.851 (3)°

• V = 842.5 (3) ų

• Z = 2

• Mo Kα radiation

• μ = 0.08 mm⁻¹

• T = 291 (2) K

• 0.24 × 0.22 × 0.20 mm

Data collection

• Bruker SMART APEX CCD diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2000 ▶) T _min = 0.98, T _max = 0.98

• 6535 measured reflections

• 1661 independent reflections

• 1085 reflections with I > 2σ(I)

• R _int = 0.045

Refinement

• R[F ² > 2σ(F ²)] = 0.048

• wR(F ²) = 0.101

• S = 1.01

• 1661 reflections

• 109 parameters

• H-atom parameters constrained

• Δρ_max = 0.13 e Å⁻³

• Δρ_min = −0.12 e Å⁻³

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 2000 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

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

supplementary crystallographic information

Comment

Bipyridyl-type bidentate Schiff base ligands have been utilized intensively to assemble various coordination polymers with interesting topologies and fascinating structural diversities (Cho et al., 2006; Mahmoudi et al., 2007; Wang et al., 2008). We report here the crystal structure of the title compound.

A perspective view of the title compound, including the atomic numbering scheme, is shown in Fig. 1. The title compound crystallizes around a crystallographic center with half a molecule in the asymmetric unit. The bond lengths and angles are within normal ranges. The terminal pyridyl groups are coplanar, and they form a dihedral angle of 71.85 (8)° with the central benzene ring. The molecular structure is stabilized by an intramolecular C9—H9···N2 bond (Table 1), but no classical intermolecular interactions have been found in the crystal packing of the title compound.

Experimental

The title compound was synthesized and purified according to the method described by by Haga et al. (1985), by the condensation reaction of pyridine-3-carboxaldehyde and 1,4-benzenedimethanamine (yield 83%). Colorless block single crystals (m.p. 397–397.2 K) suitable for X-ray analysis were obtained by slow evaporation of a methanol solution at room temperature. Analysis calclated for C₂₀H₁₈N₄: C 76.41, H 5.77, N 17.82%; found: C 76.53, H 5.74, N 17.75%. IR (KBr pellet, cm^-1): 3436 (b), 3060 (m), 3048 (m), 2942 (m), 2903 (m), 2849 (m), 1640 (s), 1586 (s), 1565 (s), 1469 (s), 1434 (s), 1359 (m), 1324 (m), 1150 (w), 1015 (m), 990 (m), 848 (s), 777 (s), 739 (m), 617 (w), 571 (m), 506 (m), 403 (w).

Refinement

H atoms were assigned to calculated positions, with C—H = 0.97 (methylene) and 0.93Å (aromatic), and refined using a riding model, with U_iso(H) = 1.2 U_eq(C).

Figures

Fig. 1.

The molecular structure of the title compound (thermal ellipsoids are shown at 30% probability levels).

Crystal data

C20H18N4	F(000) = 332
Mr = 314.38	Dx = 1.239 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2797 reflections
a = 6.0990 (11) Å	θ = 2.6–27.2°
b = 14.589 (3) Å	µ = 0.08 mm−1
c = 9.9481 (18) Å	T = 291 K
β = 107.851 (3)°	Block, colorless
V = 842.5 (3) Å3	0.24 × 0.22 × 0.20 mm
Z = 2

Data collection

Bruker SMART APEX CCD diffractometer	1661 independent reflections
Radiation source: sealed tube	1085 reflections with I > 2σ(I)
graphite	Rint = 0.045
φ and ω scans	θmax = 26.0°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −7→7
Tmin = 0.98, Tmax = 0.98	k = −17→17
6535 measured reflections	l = −11→12

Refinement

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)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.101	H-atom parameters constrained
S = 1.01	w = 1/[σ2(Fo2) + (0.04P)2] where P = (Fo2 + 2Fc2)/3
1661 reflections	(Δ/σ)max < 0.001
109 parameters	Δρmax = 0.13 e Å−3
0 restraints	Δρmin = −0.12 e Å−3

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 (Ų)

	x	y	z	Uiso*/Ueq
C1	0.0338 (3)	0.59733 (9)	0.90988 (16)	0.0402 (4)
C2	0.2284 (3)	0.63315 (11)	1.00966 (18)	0.0512 (4)
H2	0.3749	0.6142	1.0117	0.061*
C3	0.2005 (3)	0.69698 (11)	1.1050 (2)	0.0592 (5)
H3	0.3278	0.7216	1.1728	0.071*
C4	−0.0183 (4)	0.72359 (11)	1.0983 (2)	0.0627 (5)
H4	−0.0346	0.7673	1.1625	0.075*
C5	−0.1780 (3)	0.62821 (11)	0.91503 (19)	0.0522 (4)
H5	−0.3091	0.6036	0.8506	0.063*
C6	0.0482 (3)	0.53005 (10)	0.80278 (16)	0.0418 (4)
H6	−0.0874	0.5064	0.7416	0.050*
C7	0.2348 (3)	0.43652 (11)	0.68220 (17)	0.0475 (4)
H7A	0.0771	0.4255	0.6247	0.057*
H7B	0.2981	0.3791	0.7264	0.057*
C8	0.3738 (3)	0.46922 (10)	0.58876 (15)	0.0390 (4)
C9	0.3934 (3)	0.56235 (10)	0.56217 (16)	0.0430 (4)
H9	0.3223	0.6050	0.6044	0.052*
C10	0.5155 (3)	0.59265 (10)	0.47492 (17)	0.0424 (4)
H10	0.5239	0.6551	0.4585	0.051*
N1	−0.2079 (3)	0.69096 (10)	1.00596 (19)	0.0667 (5)
N2	0.2369 (2)	0.50359 (9)	0.79117 (15)	0.0489 (4)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0437 (9)	0.0402 (7)	0.0394 (9)	−0.0009 (6)	0.0165 (7)	0.0070 (6)
C2	0.0458 (10)	0.0571 (10)	0.0500 (10)	0.0002 (8)	0.0134 (8)	−0.0032 (8)
C3	0.0643 (12)	0.0516 (10)	0.0579 (12)	−0.0079 (8)	0.0134 (9)	−0.0118 (8)
C4	0.0786 (14)	0.0431 (9)	0.0738 (13)	−0.0012 (9)	0.0345 (11)	−0.0131 (9)
C5	0.0470 (9)	0.0501 (9)	0.0600 (11)	0.0011 (8)	0.0169 (8)	−0.0034 (8)
C6	0.0425 (9)	0.0458 (8)	0.0374 (9)	−0.0011 (6)	0.0127 (7)	0.0029 (6)
C7	0.0467 (9)	0.0508 (8)	0.0462 (9)	0.0005 (7)	0.0161 (7)	−0.0041 (7)
C8	0.0379 (8)	0.0423 (7)	0.0333 (9)	0.0013 (6)	0.0055 (6)	−0.0063 (6)
C9	0.0464 (9)	0.0423 (7)	0.0414 (9)	0.0065 (7)	0.0149 (7)	−0.0081 (7)
C10	0.0477 (9)	0.0346 (7)	0.0442 (9)	0.0017 (6)	0.0129 (7)	−0.0025 (6)
N1	0.0609 (10)	0.0550 (9)	0.0887 (13)	0.0041 (8)	0.0297 (9)	−0.0173 (8)
N2	0.0478 (8)	0.0624 (9)	0.0393 (8)	0.0002 (6)	0.0175 (6)	−0.0074 (6)

Geometric parameters (Å, °)

C1—C5	1.384 (2)	C6—H6	0.9300
C1—C2	1.395 (2)	C7—N2	1.458 (2)
C1—C6	1.471 (2)	C7—C8	1.514 (2)
C2—C3	1.376 (2)	C7—H7A	0.9700
C2—H2	0.9300	C7—H7B	0.9700
C3—C4	1.372 (3)	C8—C10i	1.391 (2)
C3—H3	0.9300	C8—C9	1.396 (2)
C4—N1	1.325 (3)	C9—C10	1.378 (2)
C4—H4	0.9300	C9—H9	0.9300
C5—N1	1.338 (2)	C10—C8i	1.391 (2)
C5—H5	0.9300	C10—H10	0.9300
C6—N2	1.253 (2)
C5—C1—C2	116.88 (15)	N2—C7—C8	111.49 (13)
C5—C1—C6	120.51 (15)	N2—C7—H7A	109.3
C2—C1—C6	122.61 (14)	C8—C7—H7A	109.3
C3—C2—C1	119.09 (16)	N2—C7—H7B	109.3
C3—C2—H2	120.5	C8—C7—H7B	109.3
C1—C2—H2	120.5	H7A—C7—H7B	108.0
C4—C3—C2	118.78 (18)	C10i—C8—C9	117.60 (13)
C4—C3—H3	120.6	C10i—C8—C7	121.10 (13)
C2—C3—H3	120.6	C9—C8—C7	121.30 (12)
N1—C4—C3	124.15 (17)	C10—C9—C8	121.72 (13)
N1—C4—H4	117.9	C10—C9—H9	119.1
C3—C4—H4	117.9	C8—C9—H9	119.1
N1—C5—C1	124.74 (18)	C9—C10—C8i	120.68 (13)
N1—C5—H5	117.6	C9—C10—H10	119.7
C1—C5—H5	117.6	C8i—C10—H10	119.7
N2—C6—C1	122.21 (15)	C4—N1—C5	116.34 (16)
N2—C6—H6	118.9	C6—N2—C7	118.48 (14)
C1—C6—H6	118.9

Symmetry codes: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9···N2	0.93	2.55	2.858 (2)	100