research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

Crystal structure of (1E,1′E)-1,1′-(pyridine-2,6-di­yl)bis­­[N-(2,3,4,5,6-penta­fluoro­phen­yl)ethan-1-imine]

aDepartment of Chemistry and Physics, Saint Mary's College, Notre Dame, IN 46556, USA
*Correspondence e-mail: dbabbini@saintmarys.edu

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 23 May 2017; accepted 30 May 2017; online 2 June 2017)

The title compound, C21H9F10N3, represents a potential redox non-innocent pyridine di­imine ligand system. It consists of a central pyridine ring with two penta­fluoro­phenyl substituted imine groups in positions 2 and 6. The whole mol­ecule is generated by mirror symmetry, the mirror bis­ecting the N and para-C atom of the pyridine ring. The perfluoro­phenyl ring is inclined to the pyridine ring by 73.67 (8)°. In the crystal, mol­ecules stack along the a axis, but there are no significant inter­molecular inter­actions present.

1. Chemical context

The utilization of non-innocent ligand systems in organometallic chemistry can produce secondary reactivity and can result in unique mechanistic and redox properties (Babbini & Iluc, 2015[Babbini, D. C. & Iluc, V. M. (2015). Organometallics, 34, 3141-3151.]; Praneeth et al., 2012[Praneeth, V. K., Ringenberg, M. R. & Ward, T. R. (2012). Angew. Chem. Int. Ed. 51, 10228-10234.]). Redox non-innocence is generally observed with chelate ligands which possess low-lying π-systems that can allow electron transfer (Lyaskovskyy & de Bruin, 2012[Lyaskovskyy, V. & de Bruin, B. (2012). ACS Catal. 2, 270-279.]). These ligand systems allow multiple-electron redox events to take place on metal centers, which are usually relegated to single-electron events (Haneline & Heyduk, 2006[Haneline, M. R. & Heyduk, A. F. (2006). J. Am. Chem. Soc. 128, 8410-8411.]). This is useful for the utilization of benign and economically viable first-row transition metals instead of traditional noble-metal catalysts (Chirik & Wieghardt, 2010[Chirik, P. J. & Wieghardt, K. (2010). Science, 327, 794-795.]). The development of new and varied ligands systems is essential for the understanding of the structure–property relationships, which give rise to redox non-innocence. Given the significance and current inter­est in redox-active ligand systems, herein we report on the synthesis and crystal structure of a potential redox-active pyridine di­imine system containing electron-withdrawing substituents.

[Scheme 1]

2. Structural commentary

The title compound, Fig. 1[link], crystallizes in the monoclinic space group P21/m with the mirror plane, at (x, 0.25, z), bis­ecting the pyridine N atom, N1, and C atom, C1. Thus, only half of the mol­ecule is present in the asymmetric unit (Fig. 1[link]). The penta­fluoro­phenyl groups are oriented in a synclinal fashion with respect to the pyridine ring, with the two rings being inclined to one another by 73.67 (6)°. The imine nitro­gen atom, N2, is oriented in an anti-conformation with respect to the pyridine nitro­gen, N1. This orientation is in contrast with the mol­ecule acting as a tridentate ligand coordinating to the chromium ion in complex tri­chloro­(2,6-bis­(1-(penta­fluoro­phenyl­imino)­eth­yl)pyridine-N,N′,N′′)chromium(III) aceto­nitrile monosolvate (Nakayama et al., 2005[Nakayama, Y., Sogo, K., Yasuda, H. & Shiono, T. (2005). J. Polym. Sci. A Polym. Chem. 43, 3368-3375.]). Here, the imine N atoms adopt a syn-conformation upon coordination to the chromium ion.

[Figure 1]
Figure 1
The mol­ecular structure of the title compound, with the atom labelling [symmetry code: (i) x, −y + [{1\over 2}], z]. Displacement ellipsoids are drawn at the 50% probability level.

3. Supra­molecular features

In the crystal, the mol­ecules stack along the a axis (Fig. 2[link]). Despite the presence of multiple aromatic rings within the mol­ecule, there are no obvious π-stacking inter­actions; the phenyl rings are clearly offset. Thus the only inter­molecular inter­actions present are typical van der Waals inter­actions.

[Figure 2]
Figure 2
A view along the c axis of the crystal packing of the title compound.

4. Database survey

A search of the Cambridge Structural Database (CSD, V5.38, last update February 2017; Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]) for related structures reveals that the penta­fluoro­phenyl adduct reported here has been reported as a chelating ligand in the chromium complex, tri­chloro­(2,6-bis­(1-(penta­fluoro­phenyl­imino)­eth­yl)pyridine-N,N′,N′′)chromium(III) aceto­nitrile monosolvate (CSD refcode: BOMROL; Nakayama et al., 2005[Nakayama, Y., Sogo, K., Yasuda, H. & Shiono, T. (2005). J. Polym. Sci. A Polym. Chem. 43, 3368-3375.]). The mesityl and 2,6-diiso­propyl­phenyl species are well represented and the solid-state structures of these free mol­ecules have been reported; viz. SISYEA (Boyt & Chaplin, 2014[Boyt, S. M. & Chaplin, A. B. (2014). Acta Cryst. E70, o73.]) and HORSEM (Yap & Gambarotta, 1999[Yap, G. P. A. & Gambarotta, S. (1999). Private communication (CCDC deposition number 116252). CCDC, Cambridge, England.]), respectively.

5. Synthesis and crystallization

The reagent 2,6-di­acetyl­pyridine was synthesized by a previously reported method (Su & Feng, 2010[Su, B. & Feng, G. (2010). Polym Int. 59, 1058-1063.]), and the ligand was prepared by a modification of a previously reported Schiff-base condensation method (Small & Brookhart, 1999[Small, B. L. & Brookhart, M. (1999). Macromolecules, 32, 2120-2130.]).

A mixture of 2,6-di­acetyl­pyridine (1.0 g, 6.10 mmol), 2,3,4,5,6-penta­fluoro­aniline (4.07 g, 22.2 mmol) and p-tol­uene­sulfonic acid (10 mg, 0.058 mmol) in toluene (100 ml) was refluxed for 30 h during which time water was removed by a Dean–Stark apparatus. The crude yellow product was washed with cold methanol and filtered producing a pure off-white solid (yield 1.65 g, 54.8%). Colorless block-like crystals were obtained by vapor diffusion of hexa­nes into a saturated di­chloro­methane solution of the title compound. Spectroscopic data: 1H NMR (60 MHz, CDCl3): δ 8.6–7.8 (m, 3H, Py-H), 2.5 (s, 6H, CH3), and MS (ESI): m/z 494 [C21H9F10N3]H+.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1[link]. The hydrogen atoms were included in calculated positions and refined with a riding model: C—H = 0.95–0.98 Å with Uiso(H) = 1.5Ueq(C-meth­yl) and 1.2Ueq(C) for other H atoms.

Table 1
Experimental details

Crystal data
Chemical formula C21H9F10N3
Mr 493.31
Crystal system, space group Monoclinic, P21/m
Temperature (K) 120
a, b, c (Å) 4.2713 (6), 35.792 (5), 5.9516 (9)
β (°) 93.326 (2)
V3) 908.3 (2)
Z 2
Radiation type Mo Kα
μ (mm−1) 0.18
Crystal size (mm) 0.24 × 0.19 × 0.14
 
Data collection
Diffractometer Bruker APEXII CCD
Absorption correction Multi-scan (SADABS; Krause et al., 2015[Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3-10.])
Tmin, Tmax 0.697, 0.729
No. of measured, independent and observed [I > 2σ(I)] reflections 13884, 2277, 1989
Rint 0.025
(sin θ/λ)max−1) 0.666
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.088, 1.07
No. of reflections 2277
No. of parameters 158
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.36, −0.19
Computer programs: APEX3 and SAINT (Bruker, 2016[Bruker (2016). APEX3 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]), SHELXL2016 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Computing details top

Data collection: APEX3 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2016 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2016 (Sheldrick, 2015) and publCIF (Westrip, 2010).

(1E,1'E)-1,1'-(Pyridine-2,6-diyl)bis[N-(2,3,4,5,6-pentafluorophenyl)ethan-1-imine] top
Crystal data top
C21H9F10N3F(000) = 492
Mr = 493.31Dx = 1.804 Mg m3
Monoclinic, P21/mMo Kα radiation, λ = 0.71073 Å
a = 4.2713 (6) ÅCell parameters from 5126 reflections
b = 35.792 (5) Åθ = 4.6–56.5°
c = 5.9516 (9) ŵ = 0.18 mm1
β = 93.326 (2)°T = 120 K
V = 908.3 (2) Å3Block, colorless
Z = 20.24 × 0.19 × 0.14 mm
Data collection top
Bruker APEXII CCD
diffractometer
2277 independent reflections
Radiation source: sealed tube1989 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
Detector resolution: 8.33 pixels mm-1θmax = 28.3°, θmin = 2.3°
φ and ω scansh = 55
Absorption correction: multi-scan
(SADABS; Krause et al., 2015)
k = 4744
Tmin = 0.697, Tmax = 0.729l = 77
13884 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.088H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0377P)2 + 0.4768P]
where P = (Fo2 + 2Fc2)/3
2277 reflections(Δ/σ)max = 0.001
158 parametersΔρmax = 0.36 e Å3
0 restraintsΔρmin = 0.19 e Å3
Special details top

Experimental. All other reagents and solvents were purchased commercially and used without further purification. 1H NMR was collected on a Varian 60 MHz NMR. Mass spectra were collected using direct injection on a ThermoScientific TSQ-ESI Mass spectrometer.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
F10.42432 (19)0.38311 (2)0.12835 (13)0.02066 (19)
F20.2099 (2)0.45211 (2)0.02453 (13)0.0251 (2)
F30.1849 (2)0.48751 (2)0.29875 (14)0.0261 (2)
F40.3500 (2)0.45363 (2)0.68211 (14)0.0254 (2)
F50.13051 (19)0.38487 (2)0.79035 (13)0.02134 (19)
N10.2566 (4)0.2500000.4081 (2)0.0138 (3)
N20.2674 (3)0.34658 (3)0.52933 (17)0.0155 (2)
C10.6985 (4)0.2500000.7721 (3)0.0178 (4)
H10.8550450.2500010.8922100.021*
C20.5833 (3)0.28342 (3)0.6836 (2)0.0160 (3)
H20.6536460.3066550.7450440.019*
C30.3612 (3)0.28213 (3)0.5019 (2)0.0139 (2)
C40.2187 (3)0.31743 (3)0.4075 (2)0.0138 (2)
C50.0259 (3)0.31505 (4)0.1893 (2)0.0179 (3)
H5A0.0931390.3382550.1650940.027*
H5B0.1196740.2939450.1945960.027*
H5C0.1644070.3113990.0655010.027*
C60.1457 (3)0.38157 (3)0.4594 (2)0.0137 (2)
C70.2293 (3)0.39993 (3)0.2659 (2)0.0149 (2)
C80.1229 (3)0.43548 (4)0.2117 (2)0.0165 (3)
C90.0740 (3)0.45357 (3)0.3516 (2)0.0175 (3)
C100.1585 (3)0.43632 (4)0.5469 (2)0.0170 (3)
C110.0465 (3)0.40098 (3)0.5999 (2)0.0150 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
F10.0216 (4)0.0202 (4)0.0210 (4)0.0031 (3)0.0075 (3)0.0019 (3)
F20.0339 (5)0.0204 (4)0.0213 (4)0.0026 (3)0.0040 (3)0.0081 (3)
F30.0326 (5)0.0118 (4)0.0330 (5)0.0066 (3)0.0043 (4)0.0023 (3)
F40.0243 (4)0.0242 (4)0.0284 (4)0.0077 (3)0.0070 (3)0.0070 (3)
F50.0270 (4)0.0210 (4)0.0164 (4)0.0022 (3)0.0053 (3)0.0018 (3)
N10.0163 (7)0.0099 (7)0.0152 (7)0.0000.0013 (5)0.000
N20.0183 (5)0.0106 (5)0.0173 (5)0.0005 (4)0.0009 (4)0.0007 (4)
C10.0199 (9)0.0156 (8)0.0174 (8)0.0000.0037 (7)0.000
C20.0193 (6)0.0112 (6)0.0172 (6)0.0009 (4)0.0007 (5)0.0010 (4)
C30.0155 (6)0.0116 (6)0.0146 (5)0.0004 (4)0.0019 (4)0.0005 (4)
C40.0145 (6)0.0120 (5)0.0150 (5)0.0003 (4)0.0011 (4)0.0008 (4)
C50.0225 (7)0.0134 (6)0.0172 (6)0.0009 (5)0.0040 (5)0.0010 (4)
C60.0145 (6)0.0105 (5)0.0156 (6)0.0001 (4)0.0026 (4)0.0009 (4)
C70.0146 (6)0.0138 (6)0.0163 (6)0.0003 (4)0.0013 (4)0.0027 (4)
C80.0182 (6)0.0146 (6)0.0166 (6)0.0026 (5)0.0004 (5)0.0031 (5)
C90.0188 (6)0.0097 (5)0.0234 (6)0.0014 (5)0.0045 (5)0.0003 (5)
C100.0153 (6)0.0160 (6)0.0196 (6)0.0020 (5)0.0008 (5)0.0053 (5)
C110.0164 (6)0.0146 (6)0.0137 (5)0.0034 (5)0.0001 (4)0.0003 (4)
Geometric parameters (Å, º) top
F1—C71.3439 (14)C2—H20.9500
F2—C81.3348 (15)C3—C41.4974 (16)
F3—C91.3347 (14)C4—C51.4995 (17)
F4—C101.3330 (15)C5—H5A0.9800
F5—C111.3391 (14)C5—H5B0.9800
N1—C3i1.3432 (14)C5—H5C0.9800
N1—C31.3432 (14)C6—C71.3902 (17)
N2—C41.2806 (16)C6—C111.3913 (17)
N2—C61.4098 (15)C7—C81.3829 (18)
C1—C21.3857 (15)C8—C91.3787 (19)
C1—C2i1.3858 (15)C9—C101.3822 (19)
C1—H10.9500C10—C111.3824 (18)
C2—C31.3976 (17)
C3i—N1—C3117.76 (15)H5B—C5—H5C109.5
C4—N2—C6120.78 (10)C7—C6—C11116.79 (11)
C2—C1—C2i119.37 (16)C7—C6—N2123.82 (11)
C2—C1—H1120.3C11—C6—N2119.10 (11)
C2i—C1—H1120.3F1—C7—C8118.50 (11)
C1—C2—C3118.40 (12)F1—C7—C6119.40 (11)
C1—C2—H2120.8C8—C7—C6122.09 (12)
C3—C2—H2120.8F2—C8—C9120.24 (11)
N1—C3—C2122.98 (11)F2—C8—C7120.09 (12)
N1—C3—C4116.64 (11)C9—C8—C7119.67 (12)
C2—C3—C4120.35 (11)F3—C9—C8120.38 (12)
N2—C4—C3115.20 (11)F3—C9—C10119.88 (12)
N2—C4—C5126.84 (11)C8—C9—C10119.74 (11)
C3—C4—C5117.90 (10)F4—C10—C9119.96 (11)
C4—C5—H5A109.5F4—C10—C11120.23 (12)
C4—C5—H5B109.5C9—C10—C11119.80 (12)
H5A—C5—H5B109.5F5—C11—C10118.76 (11)
C4—C5—H5C109.5F5—C11—C6119.36 (11)
H5A—C5—H5C109.5C10—C11—C6121.87 (12)
C2i—C1—C2—C32.2 (3)F1—C7—C8—C9179.14 (11)
C3i—N1—C3—C23.3 (2)C6—C7—C8—C90.40 (19)
C3i—N1—C3—C4174.53 (9)F2—C8—C9—F31.46 (19)
C1—C2—C3—N10.6 (2)C7—C8—C9—F3178.34 (11)
C1—C2—C3—C4177.14 (13)F2—C8—C9—C10178.96 (11)
C6—N2—C4—C3179.98 (11)C7—C8—C9—C101.24 (19)
C6—N2—C4—C52.7 (2)F3—C9—C10—F40.11 (18)
N1—C3—C4—N2164.92 (13)C8—C9—C10—F4179.69 (11)
C2—C3—C4—N212.97 (18)F3—C9—C10—C11179.21 (11)
N1—C3—C4—C512.59 (17)C8—C9—C10—C110.38 (19)
C2—C3—C4—C5169.52 (12)F4—C10—C11—F50.92 (18)
C4—N2—C6—C762.67 (17)C9—C10—C11—F5179.76 (11)
C4—N2—C6—C11123.67 (13)F4—C10—C11—C6177.94 (11)
C11—C6—C7—F1177.46 (10)C9—C10—C11—C61.38 (19)
N2—C6—C7—F13.67 (18)C7—C6—C11—F5178.99 (11)
C11—C6—C7—C81.27 (18)N2—C6—C11—F54.89 (17)
N2—C6—C7—C8175.06 (11)C7—C6—C11—C102.15 (18)
F1—C7—C8—F21.06 (18)N2—C6—C11—C10176.25 (11)
C6—C7—C8—F2179.80 (11)
Symmetry code: (i) x, y+1/2, z.
 

Acknowledgements

The authors thank Prof. Allen Oliver and the Mol­ecular Structure Facility at the University of Notre Dame, as well as Prof. Christopher Dunlap and all of the undergraduate students in the Advanced Laboratory course at Saint Mary's College, for their help and inter­est in this project.

References

First citationBabbini, D. C. & Iluc, V. M. (2015). Organometallics, 34, 3141–3151.  Web of Science CSD CrossRef CAS Google Scholar
First citationBoyt, S. M. & Chaplin, A. B. (2014). Acta Cryst. E70, o73.  CSD CrossRef IUCr Journals Google Scholar
First citationBruker (2016). APEX3 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationChirik, P. J. & Wieghardt, K. (2010). Science, 327, 794–795.  Web of Science CrossRef CAS PubMed Google Scholar
First citationGroom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationHaneline, M. R. & Heyduk, A. F. (2006). J. Am. Chem. Soc. 128, 8410–8411.  Web of Science CSD CrossRef PubMed CAS Google Scholar
First citationKrause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationLyaskovskyy, V. & de Bruin, B. (2012). ACS Catal. 2, 270–279.  CrossRef CAS Google Scholar
First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationNakayama, Y., Sogo, K., Yasuda, H. & Shiono, T. (2005). J. Polym. Sci. A Polym. Chem. 43, 3368–3375.  Web of Science CSD CrossRef CAS Google Scholar
First citationPraneeth, V. K., Ringenberg, M. R. & Ward, T. R. (2012). Angew. Chem. Int. Ed. 51, 10228–10234.  Web of Science CrossRef CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSmall, B. L. & Brookhart, M. (1999). Macromolecules, 32, 2120–2130.  Web of Science CSD CrossRef CAS Google Scholar
First citationSu, B. & Feng, G. (2010). Polym Int. 59, 1058–1063.  CAS Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationYap, G. P. A. & Gambarotta, S. (1999). Private communication (CCDC deposition number 116252). CCDC, Cambridge, England.  Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds