2,3,5,6-Tetra­fluoro-1,4-bis­(2-pyridylmethyl­eneamino­meth­yl)benzene

He, M.-Y.; Li, C.; Yang, X.-J.; Lu, L.-D.; Wang, X.

doi:10.1107/S1600536809001172

organic compounds

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ISSN: 2056-9890

Volume 65| Part 2| February 2009| Page o331

doi:10.1107/S1600536809001172

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2,3,5,6-Tetrafluoro-1,4-bis(2-pyridylmethyleneaminomethyl)benzene

Ming-Yang He,^a,^b ^* Chao Li,^b Xu-Jie Yang,^a Lu-De Lu ^a and Xin Wang ^a

^aSchool of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210093, People's Republic of China, and ^bKey Laboratory of Fine Petro-chemical Technology, Jiangsu Polytechnic University, Changzhou 213164, People's Republic of China
^*Correspondence e-mail: hemingyangjpu@yahoo.com

(Received 1 December 2008; accepted 10 January 2009; online 17 January 2009)

The title compound, C₂₀H₁₄F₄N₄, is a flexible bis-pyridine-type ligand with an extended fluorinated spacer group between the two pyridyl functions. The centroid of the central aromatic ring is situated on a crystallographic center of inversion. The dihedral angle between the pyridine ring and the central benzene ring is 63.85 (9)°. The crystal structure exhibits intermolecular C—H⋯F hydrogen-bonding interactions.

Related literature

For background information on bis-pyridine-type Schiff base ligands see: Barboiu et al. (2006 ); Keegan et al. (2002 ); Yue et al. (2004 ). Haga et al. (1985 ) describe the synthesis of the title compound.

Experimental

Crystal data

C₂₀H₁₄F₄N₄
M_r = 386.35
Monoclinic, P 2₁ /c
a = 9.637 (3) Å
b = 7.783 (3) Å
c = 12.070 (4) Å
β = 105.940 (4)°
V = 870.5 (5) Å³
Z = 2
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 296 (2) K
0.26 × 0.24 × 0.22 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2000 ) T_min = 0.963, T_max = 0.974
7194 measured reflections
2014 independent reflections
1341 reflections with I > 2σ(I)
R_int = 0.037

Refinement

R[F² > 2σ(F²)] = 0.045
wR(F²) = 0.151
S = 1.05
2014 reflections
127 parameters
H-atom parameters constrained
Δρ_max = 0.20 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2⋯F2ⁱ	0.93	2.53	3.370 (3)	151
Symmetry code: (i) $[x-1, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

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.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809001172/im2091sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809001172/im2091Isup2.hkl

checkCIF report

Comment top

Bis-pyridine type bidentate Schiff base ligands have been utilized intensively to assemble various coordination polymers with interesting topologies and fascinating structural diversities (Barboiu et al., 2006; Keegan et al., 2002; Yue et al., 2004). We report here the crystal structure of the title compound, (I).

A perspective view of (I), including the atomic numbering scheme, is shown in Fig. 1. (I) crystallizes around a crystallographic center of inversion with a half 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 63.85 (9)° with the central benzene ring.

Related literature top

For background information on bis-pyridine-type Schiff base ligands see: Barboiu et al. (2006); Keegan et al. (2002); Yue et al. (2004). Haga et al. (1985) describe the synthesis of the title compound.

Experimental top

The title compound was synthesized and purified according to the method described by by Haga et al. (1985) performing a condensation of pyridine-2-carboxaldehyde and 2,3,5,6-tetrafluoro-1,4-benzenedimethanamine (yield 83%). Colorless block single crystals (m.p. 465.1–465.3 K) suitable for X-ray analysis were obtained by slow evaporation of a methanolic solution at room temperature. Analysis calculated for C₂₀H₁₈F₄N₄: C 61.54, H 4.62, N 14.36%; found: C 62.26, H 3.64, N 14.45%. IR (KBr pellet, cm^-1): 3445 (b), 3087 (m), 3018 (m), 2922 (m), 2868 (m), 1639 (s), 1586 (s), 1568 (s), 1489 (s), 1470 (s), 1436 (m), 1372 (m), 1335 (m), 1275 (m), 1211 (m), 1148 (w), 1063 (s), 1013 (m), 987 (s), 892 (s), 776 (s), 742 (m), 697 (m), 621 (w), 590 (m), 509 (m), 413 (w).

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); 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

	Fig. 1. The molecular structure of the title compound showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level [symmetry code: (A) 2 - x, - y, - z].
	Fig. 2. A packing diagram of the title molecule (Dashed lines indicate hydrogen bonds).

2,3,5,6-Tetrafluoro-1,4-bis(2-pyridylmethyleneaminomethyl)benzene top

Crystal data top

C₂₀H₁₄F₄N₄	F(000) = 396
M_r = 386.35	D_x = 1.474 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3894 reflections
a = 9.637 (3) Å	θ = 2.6–27.2°
b = 7.783 (3) Å	µ = 0.12 mm⁻¹
c = 12.070 (4) Å	T = 296 K
β = 105.940 (4)°	Block, colorless
V = 870.5 (5) Å³	0.26 × 0.24 × 0.22 mm
Z = 2

Data collection top

Bruker SMART CCD area-detector diffractometer	2014 independent reflections
Radiation source: fine-focus sealed tube	1341 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.037
ϕ and ω scans	θ_max = 27.6°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −12→12
T_min = 0.963, T_max = 0.974	k = −10→10
7194 measured reflections	l = −15→15

Refinement top

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.151	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.0739P)² + 0.1642P] where P = (F_o² + 2F_c²)/3
2014 reflections	(Δ/σ)_max < 0.001
127 parameters	Δρ_max = 0.20 e Å⁻³
0 restraints	Δρ_min = −0.16 e Å⁻³

Crystal data top

C₂₀H₁₄F₄N₄	V = 870.5 (5) Å³
M_r = 386.35	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 9.637 (3) Å	µ = 0.12 mm⁻¹
b = 7.783 (3) Å	T = 296 K
c = 12.070 (4) Å	0.26 × 0.24 × 0.22 mm
β = 105.940 (4)°

Data collection top

Bruker SMART CCD area-detector diffractometer	2014 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2000)	1341 reflections with I > 2σ(I)
T_min = 0.963, T_max = 0.974	R_int = 0.037
7194 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.045	0 restraints
wR(F²) = 0.151	H-atom parameters constrained
S = 1.05	Δρ_max = 0.20 e Å⁻³
2014 reflections	Δρ_min = −0.16 e Å⁻³
127 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

	x	y	z	U_iso*/U_eq
C1	0.6996 (3)	0.1926 (3)	0.52870 (19)	0.0733 (6)
H1	0.7326	0.2286	0.6049	0.088*
C2	0.5633 (3)	0.2358 (3)	0.4693 (2)	0.0781 (7)
H2	0.5047	0.2981	0.5044	0.094*
C3	0.5132 (2)	0.1855 (3)	0.3558 (2)	0.0761 (7)
H3	0.4201	0.2127	0.3128	0.091*
C4	0.6041 (2)	0.0941 (3)	0.30767 (18)	0.0624 (5)
H4	0.5734	0.0591	0.2311	0.075*
C5	0.74130 (19)	0.0548 (2)	0.37431 (15)	0.0482 (4)
C6	0.8435 (2)	−0.0426 (2)	0.32794 (16)	0.0507 (4)
H6	0.9325	−0.0738	0.3770	0.061*
C7	0.9207 (2)	−0.1847 (3)	0.18519 (18)	0.0643 (6)
H7A	0.8812	−0.2964	0.1577	0.077*
H7B	1.0053	−0.2024	0.2496	0.077*
C8	0.9627 (2)	−0.0904 (2)	0.08987 (16)	0.0538 (5)
C9	1.0951 (2)	−0.0132 (3)	0.10554 (16)	0.0547 (5)
C10	1.1317 (2)	0.0740 (2)	0.01844 (18)	0.0556 (5)
F1	1.19419 (14)	−0.02363 (18)	0.20914 (11)	0.0756 (4)
F2	1.26344 (13)	0.14574 (17)	0.04184 (11)	0.0762 (4)
N1	0.79039 (18)	0.1014 (2)	0.48488 (14)	0.0622 (5)
N2	0.81318 (17)	−0.0848 (2)	0.22290 (14)	0.0567 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0789 (15)	0.0860 (16)	0.0611 (12)	0.0097 (13)	0.0293 (11)	−0.0086 (11)
C2	0.0766 (15)	0.0762 (16)	0.0951 (18)	0.0164 (12)	0.0465 (13)	−0.0028 (13)
C3	0.0537 (11)	0.0797 (16)	0.0951 (18)	0.0162 (11)	0.0207 (11)	0.0089 (13)
C4	0.0584 (11)	0.0667 (13)	0.0620 (12)	0.0040 (10)	0.0161 (9)	−0.0002 (10)
C5	0.0519 (10)	0.0463 (10)	0.0503 (10)	−0.0013 (8)	0.0206 (8)	0.0049 (8)
C6	0.0498 (10)	0.0523 (11)	0.0539 (10)	−0.0006 (8)	0.0207 (8)	0.0059 (8)
C7	0.0798 (13)	0.0555 (12)	0.0732 (13)	0.0025 (10)	0.0472 (11)	0.0011 (10)
C8	0.0672 (12)	0.0464 (11)	0.0597 (11)	−0.0007 (9)	0.0373 (10)	−0.0084 (8)
C9	0.0618 (11)	0.0549 (11)	0.0537 (10)	−0.0018 (9)	0.0267 (9)	−0.0124 (8)
C10	0.0577 (11)	0.0512 (11)	0.0688 (12)	−0.0102 (9)	0.0354 (10)	−0.0153 (9)
F1	0.0769 (8)	0.0893 (10)	0.0619 (8)	−0.0030 (7)	0.0213 (6)	−0.0061 (6)
F2	0.0663 (7)	0.0819 (9)	0.0898 (9)	−0.0222 (6)	0.0376 (7)	−0.0141 (7)
N1	0.0599 (10)	0.0747 (11)	0.0535 (9)	0.0079 (8)	0.0179 (7)	−0.0038 (8)
N2	0.0602 (9)	0.0624 (10)	0.0566 (9)	−0.0033 (8)	0.0316 (7)	0.0011 (7)

Geometric parameters (Å, º) top

C1—N1	1.343 (3)	C6—H6	0.9300
C1—C2	1.355 (3)	C7—N2	1.464 (2)
C1—H1	0.9300	C7—C8	1.511 (3)
C2—C3	1.378 (3)	C7—H7A	0.9700
C2—H2	0.9300	C7—H7B	0.9700
C3—C4	1.375 (3)	C8—C9	1.375 (3)
C3—H3	0.9300	C8—C10ⁱ	1.379 (3)
C4—C5	1.380 (3)	C9—F1	1.351 (2)
C4—H4	0.9300	C9—C10	1.376 (3)
C5—N1	1.338 (2)	C10—F2	1.344 (2)
C5—C6	1.470 (3)	C10—C8ⁱ	1.379 (3)
C6—N2	1.264 (2)

N1—C1—C2	124.4 (2)	N2—C7—C8	109.82 (16)
N1—C1—H1	117.8	N2—C7—H7A	109.7
C2—C1—H1	117.8	C8—C7—H7A	109.7
C1—C2—C3	118.6 (2)	N2—C7—H7B	109.7
C1—C2—H2	120.7	C8—C7—H7B	109.7
C3—C2—H2	120.7	H7A—C7—H7B	108.2
C4—C3—C2	118.5 (2)	C9—C8—C10ⁱ	115.87 (17)
C4—C3—H3	120.7	C9—C8—C7	122.69 (19)
C2—C3—H3	120.7	C10ⁱ—C8—C7	121.43 (18)
C3—C4—C5	119.2 (2)	F1—C9—C8	119.61 (17)
C3—C4—H4	120.4	F1—C9—C10	118.19 (18)
C5—C4—H4	120.4	C8—C9—C10	122.21 (19)
N1—C5—C4	122.76 (18)	F2—C10—C9	118.03 (19)
N1—C5—C6	115.41 (16)	F2—C10—C8ⁱ	120.04 (17)
C4—C5—C6	121.82 (18)	C9—C10—C8ⁱ	121.93 (18)
N2—C6—C5	121.41 (17)	C5—N1—C1	116.50 (17)
N2—C6—H6	119.3	C6—N2—C7	117.46 (17)
C5—C6—H6	119.3

N1—C1—C2—C3	−0.8 (4)	C10ⁱ—C8—C9—C10	−0.5 (3)
C1—C2—C3—C4	−0.2 (4)	C7—C8—C9—C10	−179.29 (17)
C2—C3—C4—C5	0.5 (4)	F1—C9—C10—F2	−0.8 (3)
C3—C4—C5—N1	0.3 (3)	C8—C9—C10—F2	179.80 (16)
C3—C4—C5—C6	179.96 (19)	F1—C9—C10—C8ⁱ	179.86 (16)
N1—C5—C6—N2	−175.63 (17)	C8—C9—C10—C8ⁱ	0.5 (3)
C4—C5—C6—N2	4.7 (3)	C4—C5—N1—C1	−1.2 (3)
N2—C7—C8—C9	108.5 (2)	C6—C5—N1—C1	179.09 (18)
N2—C7—C8—C10ⁱ	−70.3 (2)	C2—C1—N1—C5	1.5 (4)
C10ⁱ—C8—C9—F1	−179.83 (16)	C5—C6—N2—C7	−178.80 (16)
C7—C8—C9—F1	1.3 (3)	C8—C7—N2—C6	−122.2 (2)

Symmetry code: (i) −x+2, −y, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···F2ⁱⁱ	0.93	2.53	3.370 (3)	151

Symmetry code: (ii) x−1, −y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula	C₂₀H₁₄F₄N₄
M_r	386.35
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	9.637 (3), 7.783 (3), 12.070 (4)
β (°)	105.940 (4)
V (Å³)	870.5 (5)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.12
Crystal size (mm)	0.26 × 0.24 × 0.22

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2000)
T_min, T_max	0.963, 0.974
No. of measured, independent and observed [I > 2σ(I)] reflections	7194, 2014, 1341
R_int	0.037
(sin θ/λ)_max (Å⁻¹)	0.652

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.151, 1.05
No. of reflections	2014
No. of parameters	127
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.20, −0.16

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···F2ⁱ	0.9300	2.5300	3.370 (3)	151.00

Symmetry code: (i) x−1, −y+1/2, z+1/2.

Acknowledgements

The authors thank the Center for Testing and Analysis at Yangzhou University for support.

References

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