Acta Cryst. (2008). E64, o1710 [ doi:10.1107/S1600536808024744 ]
In the title compound, C20H19F2NO, a crystallographic mirror plane bisects the molecule, passing through the N, O and two C atoms of the central ring system. The molecule exists in a twin-chair conformation with equatorial dispositions of the 4-fluorophenyl groups on both sides of the secondary amino groups; the dihedral angle between the aromatic ring planes is 28.67 (3)°.
A mixture of cyclohexanone (0.05 mol) and para fluorobenzaldehyde (0.1 mol) was added to a warm solution of ammonium acetate (0.075 mol) in 50 ml of absolute ethanol. The mixture was very gently warmed on a hot plate till the yellow color formed during the mixing of the reactants and allowed to stir till the formation of the product. Thus, the formed azabicyclononane was separated by filtration and washed with a 1:5 v/v ethanol-ether mixture till the solid became colorless. Then, recrystallization of the compound from ethanol afforded colorless blocks of (I).
The nitrogen H atom was located in a difference Fourier map and refined isotropically. Other hydrogen atoms were fixed geometrically (C—H = 0.93-0.97Å) and refined as riding with Uiso(H) = 1.2Ueq(C).
Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
![[Figure 1]](./hb2763fig1thm.gif)
| Fig. 1. The molecular structure of (I) with non-hydrogen atoms represented as 30% probability ellipsoids. |
| C20H19F2NO | F(000) = 688 |
| Mr = 327.36 | Dx = 1.339 Mg m−3 |
| Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: -P 2ac 2n | Cell parameters from 4451 reflections |
| a = 7.6153 (3) Å | θ = 3.4–28.0° |
| b = 21.1392 (9) Å | µ = 0.10 mm−1 |
| c = 10.0878 (4) Å | T = 298 K |
| V = 1623.95 (11) Å3 | Block, colourless |
| Z = 4 | 0.35 × 0.32 × 0.30 mm |
| Bruker APEXII CCD diffractometer | 2064 independent reflections |
| Radiation source: fine-focus sealed tube | 1596 reflections with I > 2σ(I) |
| graphite | Rint = 0.020 |
| ω scans | θmax = 28.3°, θmin = 1.9° |
| Absorption correction: multi-scan (SADABS; Bruker, 2004) | h = −8→10 |
| Tmin = 0.967, Tmax = 0.971 | k = −28→28 |
| 11360 measured reflections | l = −13→12 |
| 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)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.141 | H atoms treated by a mixture of independent and constrained refinement |
| S = 0.91 | w = 1/[σ2(Fo2) + (0.0897P)2 + 0.3733P] where P = (Fo2 + 2Fc2)/3 |
| 2064 reflections | (Δ/σ)max < 0.001 |
| 118 parameters | Δρmax = 0.22 e Å−3 |
| 0 restraints | Δρmin = −0.19 e Å−3 |
| C20H19F2NO | V = 1623.95 (11) Å3 |
| Mr = 327.36 | Z = 4 |
| Orthorhombic, Pnma | Mo Kα radiation |
| a = 7.6153 (3) Å | µ = 0.10 mm−1 |
| b = 21.1392 (9) Å | T = 298 K |
| c = 10.0878 (4) Å | 0.35 × 0.32 × 0.30 mm |
| Bruker APEXII CCD diffractometer | 2064 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2004) | 1596 reflections with I > 2σ(I) |
| Tmin = 0.967, Tmax = 0.971 | Rint = 0.020 |
| 11360 measured reflections | θmax = 28.3° |
| R[F2 > 2σ(F2)] = 0.041 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.141 | Δρmax = 0.22 e Å−3 |
| S = 0.91 | Δρmin = −0.19 e Å−3 |
| 2064 reflections | Absolute structure: ? |
| 118 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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. |
| x | y | z | Uiso*/Ueq | ||
| C1 | 0.92315 (17) | 0.30735 (5) | 0.39201 (12) | 0.0391 (3) | |
| H1 | 0.8839 | 0.3055 | 0.2996 | 0.047* | |
| C2 | 0.75726 (16) | 0.30901 (5) | 0.48153 (14) | 0.0421 (3) | |
| H2 | 0.6864 | 0.3460 | 0.4576 | 0.051* | |
| C3 | 0.79266 (19) | 0.31054 (6) | 0.63140 (13) | 0.0473 (3) | |
| H3A | 0.8701 | 0.3458 | 0.6508 | 0.057* | |
| H3B | 0.6827 | 0.3181 | 0.6773 | 0.057* | |
| C4 | 0.8751 (3) | 0.2500 | 0.68562 (18) | 0.0492 (4) | |
| H4A | 0.9993 | 0.2500 | 0.6644 | 0.059* | |
| H4B | 0.8642 | 0.2500 | 0.7814 | 0.059* | |
| C5 | 0.6527 (2) | 0.2500 | 0.45348 (18) | 0.0435 (4) | |
| C6 | 1.03437 (17) | 0.36590 (5) | 0.40791 (12) | 0.0400 (3) | |
| C7 | 0.9916 (2) | 0.41937 (6) | 0.33533 (16) | 0.0543 (4) | |
| H7 | 0.8976 | 0.4179 | 0.2766 | 0.065* | |
| C8 | 1.0856 (2) | 0.47481 (7) | 0.34848 (19) | 0.0666 (5) | |
| H8 | 1.0550 | 0.5107 | 0.3003 | 0.080* | |
| C9 | 1.2238 (2) | 0.47573 (7) | 0.4334 (2) | 0.0643 (5) | |
| C10 | 1.2733 (2) | 0.42414 (8) | 0.50616 (19) | 0.0641 (4) | |
| H10 | 1.3688 | 0.4261 | 0.5634 | 0.077* | |
| C11 | 1.1771 (2) | 0.36882 (7) | 0.49220 (15) | 0.0519 (4) | |
| H11 | 1.2091 | 0.3331 | 0.5404 | 0.062* | |
| F1 | 1.31755 (17) | 0.53023 (5) | 0.44594 (17) | 0.1030 (5) | |
| H111 | 1.121 (3) | 0.2500 | 0.369 (2) | 0.047 (5)* | |
| N1 | 1.0241 (2) | 0.2500 | 0.41923 (15) | 0.0384 (3) | |
| O1 | 0.50237 (19) | 0.2500 | 0.41536 (17) | 0.0626 (4) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| C1 | 0.0441 (7) | 0.0372 (6) | 0.0359 (6) | 0.0013 (5) | −0.0009 (5) | 0.0021 (4) |
| C2 | 0.0395 (6) | 0.0368 (6) | 0.0500 (7) | 0.0045 (5) | −0.0010 (5) | 0.0018 (5) |
| C3 | 0.0493 (7) | 0.0465 (7) | 0.0461 (7) | −0.0017 (6) | 0.0077 (6) | −0.0072 (5) |
| C4 | 0.0529 (10) | 0.0585 (10) | 0.0361 (9) | 0.000 | 0.0003 (8) | 0.000 |
| C5 | 0.0384 (9) | 0.0483 (9) | 0.0437 (9) | 0.000 | −0.0027 (7) | 0.000 |
| C6 | 0.0440 (7) | 0.0352 (5) | 0.0406 (6) | 0.0016 (5) | 0.0073 (5) | 0.0021 (4) |
| C7 | 0.0567 (8) | 0.0455 (7) | 0.0605 (8) | 0.0048 (6) | 0.0044 (7) | 0.0137 (6) |
| C8 | 0.0694 (10) | 0.0390 (7) | 0.0915 (12) | 0.0051 (7) | 0.0242 (10) | 0.0157 (7) |
| C9 | 0.0586 (9) | 0.0382 (7) | 0.0961 (13) | −0.0091 (6) | 0.0292 (9) | −0.0104 (7) |
| C10 | 0.0558 (9) | 0.0579 (9) | 0.0787 (11) | −0.0105 (7) | 0.0011 (8) | −0.0110 (8) |
| C11 | 0.0529 (8) | 0.0455 (7) | 0.0572 (8) | −0.0038 (6) | −0.0029 (6) | 0.0043 (6) |
| F1 | 0.0834 (8) | 0.0474 (6) | 0.1782 (14) | −0.0225 (5) | 0.0323 (8) | −0.0170 (6) |
| N1 | 0.0377 (8) | 0.0341 (7) | 0.0434 (8) | 0.000 | 0.0057 (6) | 0.000 |
| O1 | 0.0421 (8) | 0.0693 (10) | 0.0763 (11) | 0.000 | −0.0159 (7) | 0.000 |
| C1—N1 | 1.4613 (14) | C5—C2i | 1.5067 (15) |
| C1—C6 | 1.5083 (16) | C6—C11 | 1.381 (2) |
| C1—C2 | 1.5533 (18) | C6—C7 | 1.3856 (17) |
| C1—H1 | 0.9800 | C7—C8 | 1.380 (2) |
| C2—C5 | 1.5067 (15) | C7—H7 | 0.9300 |
| C2—C3 | 1.536 (2) | C8—C9 | 1.357 (3) |
| C2—H2 | 0.9800 | C8—H8 | 0.9300 |
| C3—C4 | 1.5266 (17) | C9—F1 | 1.3613 (17) |
| C3—H3A | 0.9700 | C9—C10 | 1.367 (3) |
| C3—H3B | 0.9700 | C10—C11 | 1.387 (2) |
| C4—C3i | 1.5266 (17) | C10—H10 | 0.9300 |
| C4—H4A | 0.9700 | C11—H11 | 0.9300 |
| C4—H4B | 0.9700 | N1—C1i | 1.4613 (14) |
| C5—O1 | 1.208 (2) | N1—H111 | 0.89 (2) |
| N1—C1—C6 | 111.44 (10) | O1—C5—C2 | 124.12 (7) |
| N1—C1—C2 | 109.70 (10) | O1—C5—C2i | 124.12 (7) |
| C6—C1—C2 | 112.11 (9) | C2—C5—C2i | 111.76 (14) |
| N1—C1—H1 | 107.8 | C11—C6—C7 | 118.28 (12) |
| C6—C1—H1 | 107.8 | C11—C6—C1 | 122.96 (11) |
| C2—C1—H1 | 107.8 | C7—C6—C1 | 118.76 (12) |
| C5—C2—C3 | 107.16 (11) | C8—C7—C6 | 121.34 (15) |
| C5—C2—C1 | 107.58 (11) | C8—C7—H7 | 119.3 |
| C3—C2—C1 | 115.47 (11) | C6—C7—H7 | 119.3 |
| C5—C2—H2 | 108.8 | C9—C8—C7 | 118.37 (14) |
| C3—C2—H2 | 108.8 | C9—C8—H8 | 120.8 |
| C1—C2—H2 | 108.8 | C7—C8—H8 | 120.8 |
| C4—C3—C2 | 114.02 (11) | C8—C9—F1 | 118.51 (16) |
| C4—C3—H3A | 108.7 | C8—C9—C10 | 122.75 (14) |
| C2—C3—H3A | 108.7 | F1—C9—C10 | 118.74 (18) |
| C4—C3—H3B | 108.7 | C9—C10—C11 | 118.19 (16) |
| C2—C3—H3B | 108.7 | C9—C10—H10 | 120.9 |
| H3A—C3—H3B | 107.6 | C11—C10—H10 | 120.9 |
| C3i—C4—C3 | 113.91 (16) | C6—C11—C10 | 121.05 (14) |
| C3i—C4—H4A | 108.8 | C6—C11—H11 | 119.5 |
| C3—C4—H4A | 108.8 | C10—C11—H11 | 119.5 |
| C3i—C4—H4B | 108.8 | C1i—N1—C1 | 112.11 (14) |
| C3—C4—H4B | 108.8 | C1i—N1—H111 | 109.1 (7) |
| H4A—C4—H4B | 107.7 | C1—N1—H111 | 109.1 (7) |
| N1—C1—C2—C5 | −58.02 (14) | C2—C1—C6—C7 | −84.10 (15) |
| C6—C1—C2—C5 | 177.61 (10) | C11—C6—C7—C8 | −1.5 (2) |
| N1—C1—C2—C3 | 61.57 (13) | C1—C6—C7—C8 | 178.21 (13) |
| C6—C1—C2—C3 | −62.80 (13) | C6—C7—C8—C9 | 0.9 (2) |
| C5—C2—C3—C4 | 52.64 (16) | C7—C8—C9—F1 | 179.55 (15) |
| C1—C2—C3—C4 | −67.17 (15) | C7—C8—C9—C10 | 0.0 (3) |
| C2—C3—C4—C3i | −43.3 (2) | C8—C9—C10—C11 | −0.2 (3) |
| C3—C2—C5—O1 | 113.4 (2) | F1—C9—C10—C11 | −179.77 (15) |
| C1—C2—C5—O1 | −121.84 (19) | C7—C6—C11—C10 | 1.3 (2) |
| C3—C2—C5—C2i | −65.39 (17) | C1—C6—C11—C10 | −178.44 (14) |
| C1—C2—C5—C2i | 59.35 (18) | C9—C10—C11—C6 | −0.4 (2) |
| N1—C1—C6—C11 | −27.77 (17) | C6—C1—N1—C1i | −174.53 (8) |
| C2—C1—C6—C11 | 95.62 (15) | C2—C1—N1—C1i | 60.72 (16) |
| N1—C1—C6—C7 | 152.51 (13) |
| Symmetry codes: (i) x, −y+1/2, z. |
This research was supported by the second stage of BK 21 program and Pukyong National University under the 2008 Postdoc program.
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Fluorine substituted organic compounds are very impotant due to the significance of C—F bonds in some bioorganic systems (e.g. Evans & Seddon, 1997). The intermolecular and intramolecular hydrogen bonds involving fluorine atom have attracted much attention in various aspects (e.g. Ramachandran et al., 2007). Moreover, the biological activities mainly depend on the stereochemistry of the synthesized compound (e.g. Buxton & Roberts, 1996). Hence, realising the importance of the investigation of the conformation, stereochemistry and the nature of bondings in the synthesized title fluorine substituted heterocycle, (I), we have carried out single-crystal X-ray diffraction studies.
An analysis of torsion angles, asymmetry parameters and least-squares plane calculation shows that the piperidine ring adopts a near ideal chair conformation with the deviation of ring atoms N1 and C5 from the C1/C1i/C2/C2i (i = x, 1/2-y, z) plane by -0.670 (3)Å and 0.693 (3)Å respectively, QT = 0.6064 (13) Å. The cyclohexane ring deviate from the ideal chair conformation by the deviation of ring atoms C4 and C5 from the C2/C2i/C3/C3i plane by 0.522 (4)Å and 0.734 (3)Å respectively, QT = 0.5681 (14)Å (Cremer & Pople, 1975).
Compound (I) has a crystallographic mirror plane, which bisects the molecule passing through N1, C4, C5 and O1 of the central ring (Fig. 1) and exists in twin-chair conformation with equatorial orientations of the para fluoro phenyl groups on the heterocycle with the torsion angle of C5—C2—C1—C6 is 178.41 (6)°. The aryl groups are orientated at an angle of 28.67 (3)° to each other.