supplementary materials
2,3,5,6-Tetrafluoro-1,4-bis(2-pyridylmethyleneaminomethyl)benzene
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.
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).
H atoms were assigned to calculated positions, with C—H = 0.97 (methylene)
and 0.93 Å (aromatic), and refined using a riding model, with
Uiso(H) = 1.2 Ueq(C).
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).
2,3,5,6-Tetrafluoro-1,4-bis(2-pyridylmethyleneaminomethyl)benzene
top
Crystal data top
| C20H14F4N4 | F(000) = 396 |
| Mr = 386.35 | Dx = 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 | Rint = 0.037 |
| φ and ω scans | θmax = 27.6°, θmin = 2.2° |
Absorption correction: multi-scan
(SADABS; Bruker, 2000) | h = −12→12 |
| Tmin = 0.963, Tmax = 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(Fo2) + (0.0739P)2 + 0.1642P]
where P = (Fo2 + 2Fc2)/3 |
| 2014 reflections | (Δ/σ)max < 0.001 |
| 127 parameters | Δρmax = 0.20 e Å−3 |
| 0 restraints | Δρmin = −0.16 e Å−3 |
Crystal data top
| C20H14F4N4 | V = 870.5 (5) Å3 |
| Mr = 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) |
| Tmin = 0.963, Tmax = 0.974 | Rint = 0.037 |
| 7194 measured reflections | θmax = 27.6° |
Refinement top
| R[F2 > 2σ(F2)] = 0.045 | H-atom parameters constrained |
| wR(F2) = 0.151 | Δρmax = 0.20 e Å−3 |
| S = 1.05 | Δρmin = −0.16 e Å−3 |
| 2014 reflections | Absolute structure: ? |
| 127 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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 | Uiso*/Ueq | |
| 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, °) 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 codes: (i) −x+2, −y, −z. |
Hydrogen-bond geometry (Å, °) 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 codes: (ii) x−1, −y+1/2, z+1/2. |
Table 1
Hydrogen-bond geometry (Å, °) top
| D—H···A | D—H | H···A | D···A | D—H···A |
| C2—H2···F2i | 0.93 | 2.53 | 3.370 (3) | 151 |
| Symmetry codes: (i) x−1, −y+1/2, z+1/2. |
The authors thank the Center for Testing and Analysis at Yangzhou University
for support.
Barboiu, M., Petit, E., Van d Lee, A. & Vaughan, G. (2006). Inorg. Chem. 45, 484–486.
Bruker (2000). SADABS, SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.
Haga, M. & Koizumi, K. (1985). Inorg. Chim. Acta, 104, 47–50.
Keegan, J., Kruger, P. E., Nieuwenhuyzen, M. & Martin, N. (2002). Cryst. Growth Des. 2, 329–332.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Yue, Y. F., Gao, E. Q., Bai, S. Q., He, Z. & Yan, C. H. (2004). CrystEngComm, 6, 549–555.
![[Figure 1]](./im2091fig1thm.gif)
![[Figure 2]](./im2091fig2thm.gif)
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.